Regulus: Heart of the Lion | Brightest Stars | EarthSky History and mythology of Regulus. This chart is set for March 17, 2016. If you look on the nights after that, you’ll see the waxing moon moving closer to Regulus … and very bright Jupiter! How to see the star Regulus Regulus is the brightest star in the constellation Leo the Lion . It is a bluish star, well placed in the evening sky from about January to June. Regulus can be found marking the bottom of a large backwards question mark star pattern within Leo, known as The Sickle. The Sickle – with Regulus at its heart – outlines the constellation Leo the Lion’s head and forequarters. In our western skylore, Regulus is said to be the Lion’s Heart. Located along the ecliptic – or pathway of the sun, moon and planets – Regulus can be seen from around the globe. Bright planets sometimes pass near it, and every month the moon passes no more than about 5o away. Sometimes the moon occults (passes in front of) this star as seen from our earthly vantage point.

Of all stars visible from Earth, Regulus is either the 21st or 22nd brightest, depending on how you want to consider it. Strictly speaking, there are 21 stars brighter than Regulus, making it the 22nd brightest. However, the 21st brightest star, Alpha Centauri B, is just barely brighter than Regulus and appears so close to Alpha Centauri A ( Rigel Kentaurus ) that it cannot be distinguished separately. Since the human eye cannot actually see Alpha Centauri B as a separate star, perhaps the title of 21st brightest really does belong to Regulus. Regulus throughout the year. Regulus rises about an hour after sunset in early February. It is opposite the sun on or near February 18, and Regulus rises on that date at about sunset and is up all night long, reaching its highest point due south at local midnight. By early April, Regulus is well up in the southeast an hour after sunset. By early June, it’s high in the southwest an hour after sunset. And by early July, Regulus is low to the west an hour after sunset.

Although best seen in the evening in northern hemisphere in late winter and into summer, Regulus can be found at some time of night throughout the year except for about a month on either side of August 22, when the sun is located in Regulus’ direction in space. Regulus is a much larger star than our sun. Image via the Night Sky Guy . Regulus science. Regulus is about 77 light-years away. If – by some impossible magic – Regulus were to replace our sun, Earth would be doomed. First, Earth’s atmosphere would be stripped away, and shortly thereafter the oceans would begin to boil. With our protective natural shields gone, the surface of the Earth would bake under a star four times as wide and 140 times as bright as our world is accustomed to, not to mention the vastly increased bombardment of ultraviolet rays, X-rays and gamma rays. Taking all of the star’s radiation into account, Regulus pumps out nearly 350 times as much energy as our sun. Regulus rotates, or spins, rapidly. Our sun takes about a month to spin around once on its axis, but Regulus completes a single rotation in only 15.9 hours.

This rapid rotation rate causes Regulus’s equatorial regions to bulge, making the star not round like our sun but oblate, like a squashed orange. As a result, the north and south poles of Regulus have a higher surface gravity, and thus higher temperature and brightness, than the equatorial regions of Regulus. The polar regions of Regulus are several thousand degrees hotter than this star’s equator, and the poles of this star shine more brightly than the equator. If Regulus rotated slightly more rapidly (16% faster), the star would fly apart. Regulus is not the only star known to spin so fast that it has an oblate shape. The stars Altair and Achernar are also fast spinners with flattened shapes. What’s more, Regulus is a double star with a telescopically visible companion orbiting at about 100 times as far from Regulus as Pluto is from the sun. In fact, the companion itself is double, each component slightly smaller than our star and separated by about 95 astronomical units, or more than twice as far as Pluto from the sun.

In addition, a very small star – likely a white dwarf – circles Regulus at about the same distance as Mercury from the sun. So this is not one solitary star as the eye believes, but at least four. Overall, Regulus is a very hot star of spectral type B7V, meaning that it is much hotter than our sun, with a surface temperature that averages about 12,000K (roughly 21,000 degrees F). Very hot stars like this use up their nuclear fuel at a phenomenal rate, far faster than smaller stars like our sun. Thus the sun has an expected lifetime of about 10 billion years; it is about halfway through its life now. Meanwhile, hotter Regulus is likely only a few hundred million years old, but it is rapidly approaching its own death throes. The constellation Leo, with the star Regulus at its heart, as depicted on a set of constellation cards published in London c.1825. Image via Wikimedia Commons. History and mythology of Regulus. The name Regulus is from the diminutive form of the Latin rex, and means Little King.

Astronomers know Regulus as Alpha Leonis, but in times past it has been known simply as Rex, as well as by kingly names in other languages. It’s not clear how Regulus went from being a king – thought to rule celestial affairs – to being a ‘little’ king. Perhaps the thought was that Leo itself represented the King of Beasts, and there was room for one full king only. Regulus has also been called Cor Leonis, which means Heart of the Lion, the same name given to Richard the Lionhearted (although more frequently in French). The constellation Leo the Lion, of which Regulus is the most prominent member, is quite easy to visualize. As mentioned previously, Regulus dots the backwards question mark of stars that outlines the Lion’s head and mane. An easily identifiable triangle depicts the Lion’s hindquarters and tail. There is a great deal of mythology associated with Leo, perhaps the most common tale being that Leo was the Nemean Lion of the Hercules story. It is said that even in South America, some Peruvian Indians knew these stars as the Mountain Lion, whereas in China it was sometimes seen as a horse, and at other times as part of a dragon.

Christians in the Middle Ages sometimes referred to it as one of Daniel’s Lions. Regulus’ position is RA: 10h 08m 23s, dec: +11° 58′ 02″. Leo Constellation on Top Astronomer Leo Please hover over any star to get more information Leo is one of the larger constellations in the northern hemisphere. Its name means "lion" in Latin. In Greek mythology, the constellation is identified with the lion of Nemea, killed by Heracles as one of his Twelve Labours. The lion was terrorizing the town of Nemea near Corinth and its skin made it invulnerable. Heracles was unable to kill it with arrows as they bounced off the lion's skin, so he followed the beast into its cave and choked it to death. He kept the pelt and later wore it for protection in battle.

The constellation Leo is usually depicted as a crouching lion, with its head outlined by six stars that form the shape of a sickle, its heart marked by the brightest star in the constellation, [4806] alpha Leonis (Regulus), and [4807] beta Leonis (Denebola) lying on the tip of the lion's tail. Greek scholar Eratosthenes and Roman author Hyginus both say that the lion was placed among the stars because of its status as king of the beasts. The Chinese know most of the stars in the constellation as Xuanyuan, the Yellow Dragon. The Chaldeans associated the constellation with the Sun because, in those times, the Sun was passing through Leo during the summer solstice. Egyptians venerated the lion in the sky because the period of the Sun passing through the constellation coincided with the rise of the river Nile. The constellation Leo occupies an area of 947 square degrees and contains eight stars with known planets. It can be seen at latitudes between +90° and -65° and is best visible at 9 p.m. during the month of April.

The Sun is considered to be in the constellation between August 16 and September 15 in sidereal astrology and between July 24 and August 23 in tropical astrology. The brightest star in Leo is [4806] alpha Leonis, also known as Regulus ("prince" or "little king"), Basiliscus ("little king"), Cor Leonis ("the heart of the lion"), Qalb, Kabelaced, Qalb al-Asad ("the heart of the lion"), and Rex ("king"). Lying about 77.5 light-years away, Regulus is one of the brightest stars in the sky along with being the closest of the brightest stars to the ecliptic. It is a multiple system consisting of two binary star systems. Regulus A is a spectroscopic binary with a blue-white main sequence star as the primary component and a white dwarf as the companion. Regulus B and C are faint main sequence stars. [4807] beta Leonis, also known as Denebola ("the tail of the lion"), is the second brightest star in the constellation.

It is an an A-class star and a Delta Scuti type variable, with slight variations in brightness every few hours. Along with [6682] alpha Pictoris, [1538] beta Canis Minoris and stars in the open cluster IC 2391, Denebola is part of the IC 2391 supercluster, a stellar association also known as the Omicron Velorum Cluster, located in the constellation Vela. The stars in the cluster share a common motion through space, but are not gravitationally bound, which means that they were probably created in the same location. [4809] - [4815] gamma Leonis, also known as Algieba ("forehead"), is a binary star that consists of a K-class giant and a G-type giant. It appears as a bright double star with orange-red and greenish-yellow components. The primary star has a planetary companion. Together with [4812] zeta Leonis and [4814] eta Leonis, Algieba is part of the celestial sickle that marks the lion’s head.

[4812] zeta Leonis, also known as Adhafera ("the braid" or "the curl"), is a yellow-white giant 260 light-years distant. [4814] eta Leonis or Al Jabhah ("the front" or "the forehead") is a white supergiant, a suspected binary star, 2,100 light-years distant. Other notable stars in Leo include [4808] delta Leonis, also known as Zosma ("girdle") and Duhr, a main sequence star located at the lion’s hip, [4810] epsilon Leonis, also known as Ras Elased Australis or Asad Australis and Algenubi ("the southern star of the lion’s head"), a bright yellow giant, [4811] theta Leonis or Chertan ("two small ribs"), a white dwarf, and [4817] mu Leonis, also known as Rasalas and Alshemali (abbreviations of an Arabic phrase meaning "the northern star or the lion’s head"), a K-class, metal-rich giant 133 light-years distant.

The star Wolf 359 is interesting for being one of the closest stars to Earth, at 7.7 light-years’ distance. It is a very faint red dwarf and can only be seen in a telescope. The only stars nearer to Earth are [2081] alpha Centauri in the constellation Centaurus and Barnard’s Star in Ophiuchus . Another red dwarf in Leo, Gliese 436, has one the smallest known extrasolar planets in its orbit. Leo contains a number of bright galaxies. The best known ones are spiral galaxies Messier 65, Messier 66, Messier 95, Messier 96 and elliptical galaxy Messier 105. Messier 65 (NGC 3623) is 22 million light-years away. It is a intermediate spiral galaxy that forms the famous Leo Triplet group of galaxies along with Messier 66 (NGC 3627), another intermediate spiral galaxy, 95,000 light-years across in size, and NGC 3628, a barred spiral galaxy notable for an obscuring band of dust on the outer edge of its arms.

Messier 95 (NGC 3351) is another barred spiral galaxy, 33 million-light-years distant, with a ring-like star-forming area around the nucleus. Messier 96 (NGC 3368) is an intermediate spiral galaxy, the brightest one in the M96 Group, which also includes M95, M105 and nine other galaxies. Messier 105 (NGC 3379) is an elliptical galaxy with a confirmed supermassive black hole Another interesting object in the constellation is the Leo Ring, a huge primordial cloud of helium and hydrogen gas orbiting two galaxies, left over from the Big Bang. Leo Constellation: Facts, Location, Mythology, Stars, Galaxies | Constellation Guide Constellation Guide Constellations: A Guide to the Night Sky Leo Constellation Leo constellation lies in the northern sky. It is one of the zodiac constellations and one of the largest constellations in the sky. Leo represents the lion and is usually associated with the Nemean lion in Greek mythology. Its symbol is ♌.

The constellation was first catalogued by the Greek astronomer Ptolemy in the 2nd century, along with all the other constellations of the zodiac . Leo constellation is home to the bright stars Regulus and Denebola, the nearby star Wolf 359, and to a number of famous deep sky objects, among them galaxies Messier 65 , Messier 66 , Messier 95 , Messier 96 , Messier 105 , and NGC 3628 . FACTS, LOCATION & MAP Leo Constellation Map, by IAU and Sky&Telescope magazine Leo is the 12th largest constellation in size, occupying an area of 947 square degrees. It is located in the second quadrant of the northern hemisphere (NQ2) and can be seen at latitudes between +90° and -65°. The neighboring constellations are Cancer , Coma Berenices , Crater , Hydra , Leo Minor , Lynx , Sextans , Ursa Major and Virgo .

Leo contains five Messier objects: Messier 65 (M65, NGC 3623), Messier 66 (M66, NGC 3627), Messier 95 (M95, NGC 3351), Messier 96 (M96, NGC 3368), and Messier 105 (M105, NGC 3379). It has 11 stars with known planets. The brightest star in Leo is Regulus , Alpha Leonis, with an apparent visual magnitude of 1.35. There are two meteor showers associated with the constellation. The Leonids usually peak on November 17-18 every year and have a radiant near the bright star Gamma Leonis. The January Leonids are a minor shower that peaks between January 1 and 7. Leo belongs to the Zodiac family of constellations, along with Aries , Taurus , Gemini , Cancer , Virgo , Libra , Scorpius , Sagittarius , Capricornus , Aquarius and Pisces . MYTH Leo is one of the oldest constellations in the sky.

Archaeological evidence suggests that Mesopotamians had a constellation similar to Leo as early as 4000 BC. The Persians knew the constellation as Shir or Ser, Babylonians called it UR.GU.LA (“the great lion”), Syrians knew it as Aryo, and the Turks as Artan. Bablyonians knew the star Regulus as “the star that stands at the Lion’s breast,” or the King Star. Both the constellation and its brightest star were well known in most ancient cultures. The Greeks associated Leo constellation with the Nemean lion, the beast killed by Heracles during the first of his twelve labours. Both Eratosthenes and Hyginus wrote that the lion was placed among the constellations because it was the king of beasts. The lion lived in a cave in Nemea, a town located to the south-west of Corinth. It was killing the local inhabitants and could not be killed because its skin could not be pierced by any weapons. Hercules and the Nemean lion, photo: Andreas Praefcke Heracles could not kill the lion with arrows, so he trapped the lion in its cave, grappled with the beast and eventually choked it to death.

He used the lion’s claws to cut off its pelt, and then wore the pelt as a cloak, complete with the lion’s head. The cloak both protected Heracles and made him appear even more fearsome. In the sky, the six bright stars that form the shape of a sickle represent the lion’s head, and the brightest star in the constellation, Regulus (Alpha Leonis), marks the beast’s heart. Another bright star, Denebola (Beta Leonis) marks the tip of the lion’s tail. Algieba (Gamma Leonis), lies on the lion’s neck, even though its name means “the forehead.” Zosma (Delta Leonis) marks the lion’s rump. MAJOR STARS IN LEO Regulus – α Leonis (Alpha Leonis) Regulus, Alpha Leonis , is the brightest star in Leo and the 22nd brightest star in the sky. It has an apparent visual magnitude of 1.35 and is approximately 77 light years distant. Regulus is a four-star system composed of two pairs of stars.

Regulus A is a spectroscopic binary star composed of a blue-white main sequence star belonging to the spectral class B7 V, and a companion star which cannot be resolved, but is believed to be a white dwarf. The two stars complete an orbit around their common centre of mass every 40 days or so. Regulus B and Regulus C share a common proper motion. They are located at an angular distance of 177 arc seconds from Regulus A. They are dimmer main sequence stars with an apparent visual magnitude of 8.14 and 13.5. Regulus B is a K2V star and the companion is believed to belong to the spectral class M4V. The two stars are separated by about 100 astronomical units and have an orbital period of 2,000 years. The primary star of Regulus A is a young star, only a few million years old, and has 3.5 times the mass of the Sun. The star is an extremely fast rotator, with a rotation period of only 15.9 hours. As a result, it has an oblate shape.

If it were rotating 16% faster, the centripetal force provided by the star’s gravity would not be enough to hold the star together. Alpha Leonis is the closest bright star to the ecliptic. Because it lies so close to it, it is regularly occulted by the Moon and, rarely, by Mercury and Venus. In the northern hemisphere, Regulus is best seen in the evening in the late winter and spring. The only time of year when the star can’t be seen is for a month on either side of August 22, when it lies too close to the Sun. The star’s name, Regulus, means “little king” or “prince” in Latin. The star’s Greek name, Basiliscos, had the same meaning. The Arabic name for the star is Qalb al-Asad, which means “the heart of the lion.” Denebola – β Leonis (Beta Leonis) Denebola is the second brightest star in Leo and the 61st brightest star in the sky. It is a main sequence star with the stellar classification A3 V.

It has an apparent visual magnitude of 2.113 and is approximately 35.9 light years distant from Earth. The star can easily be seen without binoculars. Denebola has 75% more mass than the Sun, 173% of the solar radius, and is 12 times more luminous. It is classified as a Delta Scuti variable, which means that its brightness varies slightly over a period of a few hours. Denebola exhibits variations in luminosity of 0.025 magnitudes about ten times a day. Beta Leonis is a relatively young star. Its estimated age is less than 400 million years. Like Regulus , Denebola is a rapid rotator, which results in an oblate shape of the star, with a bulge at the equator. The star’s projected rotational velocity is 128 km/s. Denebola also exhibits a strong infrared excess, which suggests that it may have a circumstellar debris disk of dust in its orbit. The star belongs to the IC 2391 supercluster, a stellar association whose member stars share a common motion through space, but are not gravitationally bound.

Other stars that belong to this association are Alpha Pictoris in the constellation Pictor , Beta Canis Minoris in the constellation Canis Minor , and the stars in the open cluster IC 2391, also known as the Omicron Velorum Cluster, located in the constellation Vela . The name Denebola comes from the Arabic ðanab al-asad, which means “the lion’s tail.” Algieba – γ Leonis (Gamma Leonis) Gamma Leonis is a double star in Leo. Its traditional name, Algieba or Al Gieba, comes from the Arabic Al-Jabhah, which means “the forehead.” The star is sometimes also known by its Latin name, Juba. Algieba is composed of a giant star with the spectral classification K1-IIIbCN0.5 and a dimmer companion star which belongs to the spectral class G7IIICN-I. The brighter giant is 180 times more luminous than the Sun and has an apparent visual magnitude of 2.28.

The G7 class star has a visual magnitude of 3.51, is 50 times brighter than the Sun, and has 10 times the solar diameter. The two stars have an orbital period of 500 years. A planet was discovered in the orbit of the primary star in November 2009. The Gamma Leonis system has a combined apparent visual magnitude of 1.98 and is approximately 130 light years distant from the Sun. It is easy to observe in a small telescope under good conditions and appears as a bright double star with orange red and greenish yellow components. Algieba, Adhafera (Zeta Leonis), and Al Jabbah (Eta Leonis) are sometimes collectively known as the Sickle. Zosma – δ Leonis (Delta Leonis) Zosma, Delta Leonis, is another rapid rotator in Leo, with a projected rotational velocity of 180 km/s. Like Regulus and Denebola, Zosma has an equatorial bulge and an oblate shape. Zosma is a white main sequence star of the spectral type A4 V, approximately 58.4 light years from Earth.

It has a visual magnitude of 2.56. Delta Leonis is slightly larger and hotter than the Sun. It has 214% of the solar radius and is about 15 times more luminous than the Sun. In about 600 million years, it will become a red giant. The star is suspected to be a member of the Ursa Major Moving Group, a group of stars that includes most of the brightest stars in Ursa Major , that share a common origin and motion through space. The star’s traditional name, Zosma, comes from ancient Greek and means “the girdle.” Zosma is located on the lion’s hip. Chort – θ Leonis (Theta Leonis) Theta Leonis is another white main sequence star. It has the stellar classification A2 V and a mass 2.5 times that of the Sun. The star is visible to the naked eye. It has an apparent visual magnitude of 3.324 and is approximately 165 light years distant from the solar system. Theta Leonis has an estimated age of 550 million years, which means that it is much younger than the Sun.

It exhibits an excess emission of infrared, which indicates the presence of a circumstellar disk of dust. The star has a relatively high projected rotational velocity, 23 km/s. The star is sometimes known by its traditional names Chort (from the Arabic al-kharāt or al-khurt, which means “small rib”), Coxa (Latin for “hip”) and Chertan (from the Arabic al-kharātān, meaning “two small ribs”). Al Minliar – κ Leonis (Kappa Leonis) Kappa Leonis is a binary star with an apparent magnitude of 4.46, approximately 210 light years distant from the solar system. Its traditional name, Al Minliar, comes from the Arabic Minkhir al-Asad, which means “the muzzle of the lion.” The star has the stellar classificiation K2III. Alterf – λ Leonis (Lambda Leonis) Lambda Leonis is a K5-class star, about 336 light years from the Sun. It has an apparent visual magnitude of 4.32.

The star’s traditional name, Alterf, comes from the Arabic aṭ-ṭarf, which means “the view (of the lion).” Subra – ο Leonis (Omicron Leonis) Omicron Leonis is a double star in Leo. It is approximately 135 light years distant. It is sometimes known by its traditional name, Subra. The two components in the Omicron Leonis system belong to the spectral classes F9III (a giant) and A5mV (a main sequence star). They have a combined apparent visual magnitude of 3.53. Al Jabbah – η Leonis (Eta Leonis) Eta Leonis is white supergiant belonging to the spectral class A0 Ib. It has an apparent visual magnitude of 3.511 and is approximately 2,000 light years distant from Earth. While it appears relatively dim to the naked eye, the star is 5,600 times more luminous than the Sun and has an absolute magnitude of -5.60. The star is suspected to be a part of a binary system.

Adhafera – ζ Leonis (Zeta Leonis) Zeta Leonis is a giant star belonging to the spectral class F0 III. Its traditional name, Adhafera, comes from the Arabic al-ðafīrah, which means “the curl” or “the braid.” Zeta Leonis has a visual magnitude of 3.33 and is about 274 light years distant from the solar system. It is 85 times more luminous than the Sun. The star has an optical companion, 35 Leo, that has an apparent visual magnitude of 5.90. 35 Leo is located 325.9 arc seconds away from Adhafera, and only a line-of-sight companion, as it is only 100 light years distant from Earth. Ras Elased Borealis – μ Leonis (Mu Leonis) Mu Leonis belongs to the spectral class K3. It has a visual magnitude of 4.1 and is about 133 light years distant from Earth.

The star’s traditional names, Rasalas (or Ras Elad Borealis) and Alshemali are abbreviated from the Arabic phrase ra’s al-’asad aš-šamālī, which means “the northern (star) of the lion’s head.” Ras Elased Australis – ε Leonis (Epsilon Leonis) Epsilon Leonis is a bright giant of the spectral type G1 II. It has a visual magnitude of 2.98 and is the fifth brightest star in the constellation Leo. Its estimated age is 162 million years. The star is approximately 247 light years distant from Earth. The star traditional names – Ras Elased (Australis), Asad Australis and Algenubi – are derived from the Arabic phrase rās al-’asad al-janūbī, which means “the southern star of the lion’s head.” Epsilon Leonis is 288 times more luminous than the Sun, four times as massive, and it has 21 times the solar radius. It is classified as a Cepheid variable, changing by an amplitude of 0.3 magnitude every few days.

(Cepheid variables, named after Delta Cephei in Cepheus constellation , are very luminous stars that have a direct relationship between their luminosity and pulsation period, which makes these stars important standard candles for establishing distance scales.) ρ Leonis (Rho Leonis) Rho Leonis is another binary star in Leo. It has a visual magnitude of 3.856 and is approximately 5,000 light years distant. Rho Leonis has the stellar classification B1 lab, which means that it has reached the supergiant stage of its evolution. It has 21 times the Sun’s mass, 37 times the radius, and it is about 295,000 times more luminous. Rho Leonis is a runaway star and has a peculiar velocity of 30 km/s at the minimum relative to the nearby stars. The primary component in the system, the blue supergiant, has a companion located at an angular separation of 0.11 arc seconds. The companion star has an apparent visual magnitude of 4.8. ι Leonis (Iota Leonis) Iota Leonis is a spectroscopic binary star with the stellar classification F3 V.

It has a visual magnitude of 4.00 and is approximately 79 light years distant from the Sun. The components in the system are too close together to be able to resolve through a telescope. σ Leonis (Sigma Leonis) Sigma Leonis is a blue-white star belonging to the spectral class B9.5Vs. It has an apparent magnitude of 4.044 and is approximately 210 light years distant. Wolf 359 Wolf 359 is a red dwarf with the stellar classification M6.5Ve. It has an apparent visual magnitude of 13.54 and is only 7.78 light years distant. Despite its proximity to the Sun, Wolf 359 can only be seen through a large telescope. It is one of the lowest-mass stars ever discovered, as well as one of the faintest. It emits only about 0.1% of the Sun’s energy, has 8% of the Sun’s mass, and only 16% the solar radius. The star has an estimated age of less than a billion years. It has a relatively high proper motion.

Wolf 359 is classified as a flare star, one that can undergo dramatic increases in luminosity for several minutes as a result of magnetic activity on its surface. The flares from the star emit strong bursts of gamma rays and X-ray radiation. Wolf 359 is one of the nearest stars to the Sun. Only Alpha Centauri in the constellation Centaurus and Barnard’s Star in Ophiuchus are closer. Because of its proximity to Earth, the star is often mentioned in works of fiction. Star Trek fans will recognize it as the location of the Battle of Wolf 359, in which the Borg, led by the assimilated Captain Picard, obliterate the Starfleet ships, leaving few survivors, among them Benjamin Sisko, the future captain of Deep Space Nine. The star was also famously mentioned in an episode of The Outer Limits. Gliese 436 Gliese 436 is another red dwarf located relatively close to the Sun. It has a visual magnitude of 10.67 and is 33.1 light years distant. It belongs to the spectral class M2.5 V.

An extrasolar planet, Gliese 436b, was discovered in the star’s orbit in 2004, and the presence of another planet, UCF-1.01, was confirmed in 2012. CW Leonis (IRC + 10216) CW Leonis is a carbon star embedded in a thick envelope of dust. It is between 390 and 490 light years distant from the Sun. The star was first discovered in 1969 by the American astrophysicist Eric Brecklin and his team of astronomers. CW Leonis is at a late stage of its evolution, blowing off its outer layer to eventually become a white dwarf. The gaseous envelope, rich in carbon, is some 69,000 years old and the star is losing an enormous amount of mass each year. Its extended envelope is believed to have at least 1.4 solar masses of ejected material. The star exhibits variations in brightness over a period of 649 days.

It has a nominal luminosity of 11,300 times that of the Sun, but this varies over the course of the pulsation cycle, from 6,250 to 15,800 times the Sun’s luminosity. Consequently, its apparent visual magnitude varies too, ranging from 1.19 to 10.96. R Leonis R Leonis is a red giant star of the spectral type M8IIIe. It has a visual magnitude varying from 4.4 to 11.3 with a period of 312 days and is classified as a Mira variable. Mira variables are pulsating variable stars that are in the late stage of evolution, very red in colour, and with pulsation periods longer than 100 days. They eventually expel their outer envelopes to form planetary nebulae and become white dwarfs within a few million years. R Leonis is approximately 370 light years distant from the solar system. When it is at its brightest, it can be seen without binoculars, and when it is on the dimmest end of the spectrum, one needs at least a 7 cm telescope to see the star.

R Leonis has a radius 320-350 times solar. DEEP SKY OBJECTS IN LEO Messier 65, image: NASA (Wikisky) Messier 65 (M65, NGC 3623) Messier 65 is an intermediate spiral galaxy in Leo. It has an apparent visual magnitude of 10.25 and is approximately 35 million light years distant. The galaxy was discovered by Charles Messier in 1780. Messier 65 , Messier 66 and NGC 3628 form the famous Leo Triplet galaxy group. The galaxy does not contain much dust and gas and there isn’t much star formation occurring in it. Most of the stars in the galaxy are old. M65’s disk appears slightly warped, which, along with some recent starburst activity, suggests that the galaxy is interacting with another object. This image of spiral galaxy NGC 3627, also known as Messier 66, was captured by the Spitzer Infrared Nearby Galaxy Survey (SINGS) Legacy Project using the telescope’s Infrared Array Camera (IRAC).

NGC 3627 is estimated to be 30 million light-years distant and seen towards the constellation Leo. Astronomers suspect that the galaxy’s distorted shape is due to its ongoing gravitational interactions with its neighbors Messier 65 and NGC 3628. Messier 66 (M66, NGC 3627) Messier 66 is an intermediate spiral galaxy in Leo. Charles Messier discovered it in 1780. The galaxy has a visual magnitude of 8.9 and is about 36 million light years distant. M66 is approximately 95,000 light years across and notable for its dust lanes and bright star clusters. It is part of the Leo Triplet, along with M65 and NGC 3628. M66 and NGC 3628 had an encounter in the past, and the gravitational interaction between the two resulted in an extremely high central mass concentration in M66, a high molecular to atomic mass ratio, and a resolved noncorotating clump of H I material being removed from one of M66’s spiral arms.

The galaxy Messier 95 stands boldly face-on, offering an ideal view of its spiral structure. The spiral arms form an almost perfect circle around the galactic centre before they spread out, creating a mane-like effect of which any lion would be proud. Another, perhaps even more striking, feature of Messier 95 is its blazing golden core. It contains a nuclear star-forming ring, almost 2000 light-years across, where a large proportion of the galaxy’s star formation takes place. Photo: ESO Messier 95 (M95, NGC 3351) Messier 95 is a barred spiral galaxy in Leo. It has a visual magnitude of 11.4 and is approximately 38 million light years distant. The central region of M95 has a ring-shaped starburst region around the core with a diameter spanning about 2,000 light years. The galaxy was discovered by the Frech astronomer Pierre Méchain in 1781 and Charles Messier subsequently included it in his catalogue four days later.

M95 belongs to the M96 Group of galaxies, which also includes M96 and M105, and also at least nine other galaxies. A supernova was observed in M95 in March 2012. Messier 96 lies in the constellation of Leo (The Lion). It is the largest galaxy in the Leo I group of galaxies; including its outermost spiral arms, it spans some 100 000 light-years in diameter — about the size of our Milky Way. Its graceful imperfections likely result from the gravitational pull of other members in the group, or are perhaps due to past galactic encounters. Image: ESO Messier 96 (M96, NGC 3368) Messier 96 is another intermediate spiral galaxy in Leo constellation. It has an apparent visual magnitude of 10.1 and is about 31 million light years distant. M96 is the brightest galaxy in the M96 Group. M96 was discovered by Pierre Méchain on March 20, 1781 and then included in Messier’s catalogue a few days later.

The galaxy is classified as a double-barred spiral with a small inner bulge through the centre along with an outer bulge. Ultraviolet emissions from the galaxy’s central region suggest that it has a supermassive black hole at its core. A Type Ia supernova, SN 1998bu, was discovered in M96 in May 1998. Messier 105, image: ESA Messier 105 (M105, NGC 3379) Messier 105 is an elliptical galaxy in Leo. It has a visual magnitude of 10.2 and is approximately 32 million light years distant. The galaxy is known to have a supermassive black hole at its centre. M105 was discovered by Pierre Méchain in March 1781, a few days after he had first observed M95 and M96. NGC 3628 NGC 3628 hides its spiral structure because it is seen perfectly edge-on, exactly as we observe the Milky Way on a clear night.

Its most distinctive feature is a dark band of dust that lies across the plane of the disc and which is visibly distorted outwards, as a consequence of the gravitational interaction between NGC 3628 and its bullying companions. This boxy or “peanut-shaped” bulge, seen as a faint X-shape, is formed mainly of young stars and gas and dust, which create the bulge away from the plane of the rest of the galaxy through their powerful motions. Because of its appearance, NGC 3628 was catalogued as Arp 317 in the Atlas of Peculiar Galaxies, published in 1966, which aimed to characterise a large sample of odd objects that fell outside the standard Hubble classification, to aid understanding of how galaxies evolve. Image: ESO NGC 3628 is an unbarred spiral galaxy approximately 35 million light years distant from the solar system. It was discovered by William Herschel in 1784. The galaxy is notable for having a long tidal tail spanning about 300,000 light years, and a broad, obscuring dust band along the outer edge of its spiral arms.

Along with Messier 65 and Messier 66, NGC 3628 forms the Leo Triplet galaxy group. The Leo Ring The Leo Ring is an enormous primordial cloud of hydrogen and helium found in orbit of two galaxies in the Leo constellation. The cloud was discovered by radio astronomers in 1983. NGC 3607 NGC 3607 is a spiral galaxy in Leo. It has a visual magnitude of 10.8 and is a member of the Leo II Group (NGC 3607 Group) of galaxies. NGC 3593 – infrared image by Torsten Boeker, Space Telescope Science Institute, and NASA & ESA NGC 3593 Leo Constellation: Facts About the Lion Leo Constellation: Facts About the Lion By Kim Ann Zimmermann | August 1, 2012 10:58am ET MORE Leo the Lion is one of the earliest recognized constellations. The Mesopotamians are known to have documented the “lion” constellation.

The Persians called it Ser or Shir; the Turks, Artan; the Syrians, Aryo; the Jewish, Arye; the Indians, Simha. These are all translated as “lion.” Hunting the lion Leo is a highly recognizable constellation, as it is one of the few constellations that resemble its namesake. It is fairly easy to find because the “pointer stars” of the Big Dipper point to Leo. March does come in with a lion. The constellation becomes visible in the Northern Hemisphere around the spring equinox and is easily identifiable through May. Leo lies between Cancer to the west and Virgo to the east. Right ascension: 11 hours Visible between latitudes 90 and minus 65 degrees Best seen in April at 9 p.m. This sky chart shows where the constellation Leo, the Lion and its trademark sickle appear in the eastern sky as viewed from the Northern Hemisphere during spring. This chart is where the constellation appears at 8 p.m. EDT as viewed from the U.S. East Coast. Credit: Starry Night Software The constellation can be found by looking for the "sickle" starting at the Regulus (Alpha Leonis) star.

Regulus, Al Jabbah, and Algieba, together with the fainter stars ζ Leo (Adhafera), μ Leo (Ras Elased Borealis), and ε Leo (Ras Elased Australis), constitute the sickle. Another star in the planet is Al Geiba, the brightest star in the curve of the sickle, means "the lion’s mane." In January 2001, a large object eight times the size of Jupiter was discovered orbiting Al Geiba. A triangle of stars forms the lion’s haunches, with the brightest star of this trio being Denebola, which means "tail of the lion." There are a number of luminous galaxies within Leo, including the Leo triplet of M66, M65 and NGC 3628. The Leo Ring, a cloud of hydrogen and helium gas, orbits of two dwarf galaxies. Triplet of bright galaxies in the constellation of Leo (The Lion), together with a multitude of fainter objects: distant background galaxies and much closer Milky Way stars.

The image hints at the power of the VST and OmegaCAM for surveying the extragalactic Universe and for mapping the low brightness objects of the galactic halo. Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute Mythology Leo is the Nemean Lion, which was killed by Hercules on one of the 12 labors he had to perform for killing his family. According to Greek mythology, the lion that terrorized the citizens had a hide that could not punctured by iron, bronze or stone. Having broken all of his weapons fighting the man-eating lion, Hercules finally strangled it to death and placed it in the heavens as one of his conquests. Astrology is not a science , but Leo is one of the 13 constellations of the Zodiac . Leo is the fifth sign of the Zodiac and represents those born July 22 to August 22. It is considered a masculine, extroverted sign. — Kim Ann Zimmermann Constellations ancient and modern grace the skies year round. Let's see what you know about the star patterns that appear overhead every night.

Leo Constellation - Facts About Leo | Solarsystemquick.com Leo Constellation Highlighted in yellow is the asterism which forms the head of Leo, known as 'The Sickle'. Leo Constellation Facts Leo contains several bright stars making it one the most easily recognizable constellations in the night sky. The constellation is visible in both the Northern and Southern hemispheres. In the Northern hemisphere the constellation can be seen from January to June. The stars that make up the bowl of the 'Big Dipper' asterism point towards the constellation in the Northern hemisphere. In the Southern hemisphere Leo can be viewed in the summer and autumn months. In the Southern hemisphere Leo will appear upside down. The brightest star in the constellation is Regulus, which has surface temperatures more than twice that of the sun. The Latin word for lion is leo. Leo is one of the oldest recorded constellations, it was perceived as a lion by ancient civilizations as far back as 6,000 years ago. Leo is also one of the twelve signs of the zodiac. Leo Mythology The constellation of Leo was recognized as a lion by several ancient civilizations.

Like several constellations Leo is based on the adventures of Hercules, a Greek mythological hero and son of Zeus. After being driven insane by his step mother the divine hero killed his six sons in a blind rage. When he recovered from his temporary madness Hercules seeked to atone for his actions by serving a penance for his crimes. Eventually Hercules ended up in the control of King Eurystheus who set him a series of labors. The first of these labors was to kill a lion that had been terrorizing the city of Nemea. Unknown to Hercules the lion had a coat of golden fur which arrows and swords were unable to penetrate. On his first visit to the lion’s lair Hercules discovered that his arrows simply bounced of the beast. On his second visit the hero blocked off one of the two entrances to the lair and entered armed with a large club, he beat the lion with his club before strangling it to death. Main Stars in the Leo Constellation The number next to each star is its apparent magnitude, its brightness from our point of view on Earth, the lower the number the brighter the star in the night sky.

Denebola Also known as Beta Leonis, Denebola is a bright white main sequence star located around 36 light years from Earth, the star is only 75% larger in mass and radius than our sun. Zosma Also known as Delta Leonis, like Denebola Zosma is a white main sequence star located around 58 light years from Earth, the star has a mass and radius around twice that of the sun. Chort Also known as Theta Leonis, along with Denebola and Zosma Chort forms the rump of Leo in the form of a bright triangle, like the two others Chort is a white main sequence star, at a distance of 165 light years from Earth it is the furthest of the trio and as a result less bright. Regulus Also known as Alpha Leonis, Regulus is not only the brightest star in the constellation but one of the brightest stars in the night sky. Regulus is a four star system located around 80 light years from Earth, the system consists of the bright Regulus A and three dimmer stars.

Regulus A is a large blue main sequence star with around 4 times the mass and radius of the sun. Algieba Also known as Gamma Leonis, Algieba is a two star system around 130 light years from Earth, the system consists of two giant binary stars orbiting each other at a distance of around 16 billion miles (26 billion km). Adhafera Also known as Zeta Leonis, Adhafera is a white-yellow giant star around 270 light years from Earth, it's around six times larger in diameter than the sun with around three times its mass. Finding Leo - Northern Hemisphere The chart shows the position of Leo over most of the United States in mid-spring at 10 pm. This chart can also be applied to other areas of the Northern hemisphere such as Canada, the UK and Europe. In the Northern hemisphere Leo is primarily visible in the southern night sky. In January Leo will appear low on the eastern horizon around 11 pm, moving westwards throughout the night until day breaks around 7pm. From February to April the constellation will appear in the eastern sky around 8 pm, gradually moving higher before dipping towards the western horizon before day breaks.

In May and June Leo will appear high in the western night sky around 10 pm, before dipping towards the western horizon over the next few hours. Finding Leo - Southern Hemisphere The chart shows the position of Leo over most of Australia in early autumn at 8 pm. This chart can also be applied to other areas of the Southern hemisphere such as New Zealand, South Africa and South America. In the Southern hemisphere Leo is visible in the northern night sky. In February and March Leo will appear low in the north-eastern sky from around 9 pm, moving westwards throughout the night before dipping below the north-western horizon around day break. Throughout autumn months of April to June the constellation will appear in the north-eastern or northern sky around 6pm, gradually moving towards the north-western horizon over the next few hours. Share this page Leo? Here's your constellation | Constellations | EarthSky EarthSky’s 2015 fund-raising campaign goes until April 16! Donate. Constellation Leo, by EarthSky Facebook friend Dennis Chabot. How to see the constellation Leo.

From a Northern Hemisphere perspective, the Lion is a fair-weather friend, springing into the early evening sky around the March 20 equinox. Late March, April and May are superb months for identifying Leo the Lion, as this constellation becomes visible as soon as darkness falls and stays out until the wee hours of the morning. Remember, you are looking for a backwards question mark pattern. This pattern is the Sickle; its curve outlines the Lion’s mane. Leo’s brightest star, Regulus, is a sparkling blue-white beauty of a star. It’s located at the bottom of the backwards question mark pattern and depicts the Lion’s heart. A triangle of stars in eastern Leo represents the Lion’s hindquarters and tail. The brightest star of the triangle is named Denebola, which stems from an Arabic term meaning the Lion’s Tail. Like all stars, Leo’s stars return to the same place in the sky some four minutes earlier daily or two hours earlier monthly. In early April, the constellation Leo reaches its high point for the night around 10 p.m. local time (11 p.m. local daylight saving time), and starts to sink below the western horizon around 4 a.m. local time (5 a.m.

local daylight saving time). By around May 1, Leo reaches his high point for the night around 8 p.m. local time (9 p.m. local daylight saving time). Also, in early May, the mighty Lion begins to set in the west around 2 a.m. local time (3 a.m. daylight saving time). By June, you’ll find Leo descending in the west in the evening. Though Leo drifts progressively westward in the early evening sky as the months go by, the Lion can be viewed in the evening till July. By late July or early August, the Lion begins to fade into the sunset, not to return to the eastern predawn sky until late September or October. An imaginary line drawn between the pointer stars in the Big Dipper – the two outer stars in the Dipper’s bowl – points in one direction toward Polaris, the North Star, and in the opposite direction toward Leo. Image via Urania's Muse at Wikimedia Commons Find Leo by star-hopping from the Big Dipper. If you’re familiar with the Big Dipper asterism, you can star-hop to Leo the Lion every time. To find Leo, first find the Big Dipper.

In March, the Big Dipper stands pretty much on its handle in the northeast sky at nightfall. At nightfall in April, look for the Big Dipper higher in the northeast sky, and at nightfall in May, look for the upside-down Big Dipper high in the north, above Polaris, the North Star. Then identify the two pointer stars of the Big Dipper – that is, the two outer stars in the Big Dipper’s bowl. An imaginary line drawn between these stars points in one direction toward Polaris , the North Star. And it points in the opposite direction toward Leo. Constellation Leo in history and myth. Leo the Lion has long been associated with the sun. The sun passes in front of the constellation Leo the Lion from about August 10 to September 16 each year. The ancient Egyptians held Leo in the highest esteem, because the sun shone in front of this constellation at the time of the annual flooding of the Nile River, the lifeblood of this agricultural nation. It’s thought that the various lion-headed fountains designed by Greek and Roman architects symbolize the life-giving waters being released by the sun’s presence in Leo.

In astrology, Leo – one of the three fire signs of the Zodiac – is ruled by the sun. Many stories are associated with Leo the Lion. Perhaps the two better-known tales feature Hercules’ first labor with the notorious Nemean Lion, and the Roman author Ovid’s rendering of the tragic love affair of Pyramus and Thisbe. Image credit: Wikimedia Commons What can you see with a telescope in Leo? Check out the chart above to get a sense of the telescopic riches that lie within the boundaries of this constellation. The star Algieba is a double star, visible in a small telescope when the atmosphere is steady. If the stars are twinkling wildly, that indicates a turbulent – not steady – atmosphere. On the other hand, if the stars are twinkling very little or not at all, try your luck at splitting Algieba – which looks like a single star to the eye – into its two colorful component stars with the telescope. A close-knit pair of galaxies in Leo also provide an inviting target for the telescope: M65 and M66. With a low-powered telescope, you might be able fit both M65 and M66 into a single field of view.

Once you have done performed that feat, try your luck with the other galaxy pair: M95 and M96. Bottom line: The constellation Leo the Lion is east to overhead on spring evenings. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle. You can use the Pointer stars of the Big Dipper to find Leo. Leo's Bright Star Regulus Flies like Bullet Leo's Bright Star Regulus Flies like Bullet By Tariq Malik, Space.com Managing Editor | January 31, 2005 07:00am ET MORE This computer model shows Regulus (left) and the Sun as they would appear side by side. Here, Regulus is tilted so that its axis, denoted by the dotted line, is near horizontal. Credit: CHARA/GSU/H.McAllister. Shining brightly in the constellation Leo is a fast-spinning star that shoots through the cosmos like an extra-wide bullet, perplexing astronomers as it moves through space in the same direction as its polar axis.

Researchers have long known that Regulus, the brightest star in Leo, spins much faster than the Sun, but new observations with an array of telescopes pinned down the star's odd motion and a host of other characteristics. "We don't have any idea why it's really doing that," said Georgia State University astronomer Hal McAlister, who led the study of the star at the university's Center for High Angular Resolution (CHARA). "The picture makes me wonder what it would be like to be in a solar system with this type of star." Regulus' axis is tilted about 86 degrees, presenting astronomers on Earth with an askew view of the star. Using the CHARA array of telescopes atop California's Mount Willson, McAlister and his team were able to make the first observations of how Regulus is shaped by its high-speed rotation: 700,000 miles (1.1 million kilometers) an hour spin at its equator.

With such a high rate of rotation -- the Sun, for comparison, has an equatorial spin of about 4,500 miles (7,242 kilometers) an hour -- Regulus bulges out at the center to a diameter about 4.2 times that of Earth's home star. If Regulus spun just 10 percent faster it would rip itself apart, but that's not likely, researchers said. "There's nothing that we know of that can speed this star up," McAlister told SPACE.com. Although Regulus shines about 350 times brighter than the Sun, it burns hotter at its poles (15,100 degrees Celsius) than at the equator (10,000 degrees Celsius), where the pull of gravity is diminished by the star's distorted shape which in turn lowers the temperature, researchers said, adding that the poles shine five times brighter than the equator. Researchers used measurements of the CHARA array's six telescopes to determine Regulus' temperature, speed spin axis orientation along with a light-combining method called interferometry. McAlister said that the Regulus study is just the start of observations with the CHARA array.

"Literally we have thousands of other targets to choose from for future study," he said, adding after studying the young, hot Regulus, he'd like to measure the diameters of cooler, older stars. "We're only beginning to dip our toes in this ocean." This article is part of SPACE.com's weekly Mystery Monday series. Author Bio Tariq Malik, Space.com Managing Editor Tariq joined Purch's Space.com team in 2001 as a staff writer, and later editor, covering human spaceflight, exploration and space science. He became Space.com's Managing Editor in 2009. Before joining Space.com, Tariq was a staff reporter for The Los Angeles Times. He is also an Eagle Scout (yes, he has the Space Exploration merit badge) and went to Space Camp four times as a kid and a fifth time as an adult. He has journalism degrees from the University of Southern California and New York University. To see his latest project, you can follow Tariq on Google+ , Twitter and on Facebook . Tariq Malik, Space.com Managing Editor on Subscribe To SPACE.com

Question: What is the brightest star in the constellation Leo?
Answer: REGULUS