recursal/Fanatic-Fandom huggingface dataset:
Proxima Centauri d

Proxima Centauri d is an exoplanet located 4.22 light-years away from Earth orbiting the closest star to the Solar System, Proxima Centauri. The first signs of the exoplanet emerged as a weak 5.15-day signal in radial velocity data taken from the Very Large Telescope during a 2020 study on Proxima b's mass. This signal was formally proposed to be a candidate exoplanet by Faria et al. In a follow-up paper published in February 2022. Proxima d is a sub-Earth at least one quarter the mass of Earth or twice the mass of Mars. It orbits roughly 0.029AU from its star, orbiting it every 5.1 days. It is the least massive and innermost known planet of the Proxima Centauri system. The planet is the least massive exoplanet detected with the radial velocity method as of 2022. Proxima d orbits too close to its star to be habitable—assuming an Earth-like reflectivity, its equilibrium temperature may reach 87 °C. It is one of the smallest and least massive exoplanets found.

## Discovery

The researchers published their peer-reviewed findings in the journal *Astronomy & Astrophysics* on February 10, 2022. As with the previous planetary discoveries at Proxima Centauri, the researchers used the Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) instrument on VLT to confirm its probable planetary nature. The researchers needed ESPRESSO’s greater precision for additional confirmation, because the planetary signal was weak.
Harry and Harriot - Harry meets Harriot/transcript

## Captions

Harry: This Will Be a Good Day

Harry's Brain: !HOT GIRL ALERT!

Harry's Brain: !HOT GIRL ALERT!

Harry: OMG PRETTY GAL

Harry: hey gal

Harriot: wut

Harry: Hello!

*Harry starts "dying"*

Harriot: wut

Harriot: Screw it, can i be ur GF.

Harry: y-yes

Harry's Brain: YESSSSS

## Actual Transcript

*Harry is walking down the street.*

Harry: Lah la-la-la-la-la!

*Harriot walks in.*

*Harry's Brain alarm goes off for "Pretty Gal"*

Harry: Right! HOHO! Pretty Girl!

Harry: What do I say?

*Harry starts to stutter.*

Harry: Hey!

Harriot: What?

Harry: Hello!

*Harry stutters more and coughs mid way through.*

Harriot: What?

Harriot: You know what? You look pretty cute, can I be your Boyfriend?

Harry's Brain: Yeah! Code re- No!

Harry: Y-Yes.

Harry's Brain: yesssss!

## Errors

* Harriot say can I be your "Boyfriend" instead of Girlfriend.
Europa

Europa is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 80 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Europa was discovered in 1610 by Galileo Galilei and was named after Europa, the Phoenician mother of King Minos of Crete and lover of Zeus (the Greek equivalent of the Roman god Jupiter).

Slightly smaller than Earth's Moon, Europa is primarily made of silicate rock and has a water-ice crust and probably an iron–nickel core. It has a very thin atmosphere, composed primarily of oxygen. Its white-beige surface is striated by light tan cracks and streaks, but there are relatively few craters. In addition to Earth-bound telescope observations, Europa has been examined by a succession of space-probe flybys, the first occurring in the early 1970s.

Europa has the smoothest surface of any known solid object in the Solar System. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath the surface, which could conceivably harbour extraterrestrial life. The predominant model suggests that heat from tidal flexing causes the ocean to remain liquid and drives ice movement similar to plate tectonics, absorbing chemicals from the surface into the ocean below. Sea salt from a subsurface ocean may be coating some geological features on Europa, suggesting that the ocean is interacting with the sea floor. This may be important in determining whether Europa could be habitable. In addition, the Hubble Space Telescope detected water vapour plumes similar to those observed on Saturn's moon Enceladus, which are thought to be caused by erupting cryogeysers. In May 2018, astronomers provided supporting evidence of water plume activity on Europa, based on an updated analysis of data obtained from the Galileo space probe, which orbited Jupiter from 1995 to 2003. Such plume activity could help researchers in a search for life from the subsurface European ocean without having to land on the moon.

The Galileo mission, launched in 1989, provides the bulk of current data on Europa. No spacecraft has yet landed on Europa, although there have been several proposed exploration missions. The European Space Agency's Jupiter Icy Moon Explorer (JUICE) is a mission to Ganymede that is due to launch in 2023 and will include two flybys of Europa. NASA's planned Europa Clipper should be launched in 2024.
Arcturus

Arcturus is a star located 36.7 light-years away from Earth in the constellation Boötes. It is the fourth-brightest star in the night sky. However, Alpha Centauri AB consists of two components – Alpha Centauri A and Alpha Centauri B – both of which are fainter than Arcturus, even though their combined magnitude is -0.27. Alpha Centauri A has an apparent magnitude of +0.01 and Alpha Centauri B, +1.33, while Arcturus shines at magnitude -0.05. This makes Arcturus the third individual brightest star in the sky.

When viewed from Earth, it appears to be positioned almost at the north galactic pole of the Milky Way. Arcturus is a single red giant. It is an ageing star around 7.1 billion years old that has used up its core hydrogen and evolved off the main sequence. It is about the same mass as the Sun, but has expanded to 25 times its size and is around 170 times as luminous.

Arcturus was not visible from Earth until about half a million years ago. It has been moving in our direction and has now almost reached its closest point to the solar system, moving at 122 km/s relative to the Sun. It will make the closest approach in approximately 4,000 years, coming a few hundredths of a light-year closer than it is now. Arcturus will then start to move away in a southerly direction and, in another half million years, it will not be visible to the unaided eye at all.

Arcturus’ nearest known neighbour is Muphrid, a binary star located at almost the same distance from the Sun (37.2 light years), that appears close to Arcturus in the sky. The two stars are separated by only 3.3 light years. An observer on a hypothetical planet orbiting Arcturus would see Muphrid as a magnitude -2.5 star (roughly the brightness of Mercury), while Arcturus would appear as bright as Venus (magnitude -4.92 to -2.98) to an observer on a planet orbiting Muphrid.
Death Logs

## Harry and Harriot - Ruben's Revenge

* 0:25 27th August 2021 - Tankman got shot by a Ball. Cause of Death: Robot
* 1:01 27th August 2021 - Meat Boy got Squashed. Cause of Death: Robot

## Harry and Harriot - Minions and Defeatance

* 0:19 4th September 2021 - Kevin burns in Lava. Cause of Death: Tricky
* 0:29 4th September 2021 - Bob burns in Lava. Cause of Death: Ruben with the Power Vent
* 0:36 4th September 2021 - Stuart burns in Lava. Cause of Death: Harry

## Harry and Harriot - Forgiveness

* 0:56 11th September 2021 - Bread gets eaten. Cause of Death: Parrot
Football Pitch

The Football Pitch is a Minor Place.

## History

When Tankman plays, he kicks the ball and hits BadBoyHalo and Robot.

## Trivia

* The Football Club consists of:
	+ Manager
	+ Tankman
	+ Meat Boy
	+ Tricky
		- Possibly Robot, as he wears one.
* It is unknown where this really is.
	+ Although, it must be close to Harry, Harriot and Ruben as it landed near them and hit Robot.
Balloon Truck

The balloon Truck is an item from the Thomas and Friends Plarail range, it was released in June 2007 and Discontinued in August 2018. They Were only sold with the Plarail and trackmaster Rosie. They where available in 4 Colors, Red, Blue, Yellow, and Green. The Rarest is Yellow and the Most Common is Red.
Harry and Harriot - Robot attack

Robot attack is the 3rd Episode in Season 1.

## Plot

We see that Harry and Harriot are arguing over keeping Ruben or not. Ruben then points out Robot's existence. It then cuts to Tankman, Meat Boy and Tricky playing football with Manager. Tankman then kicks the ball and misses. He hits BadBoyHalo and it ricocheted off him and hit Robot. Robot then woke up and trapped Harry and Harriot in a tube. He then sees Ruben and wants to kill him. It is then left off here.

## Characters

### Main Characters

* Harry
* Harriot

### Major Characters

* Ruben
* Robot (Debut)

### Minor Characters

* Tankman (Debut)
* Meat Boy (Debut)
* Tricky (Debut)
* Manager (Debut)
* BadBoyHalo (Debut)

## References

0:09 - Among Us Imposters are referenced.

0:31 and 0:40 - The Spongebob French Narrator saying "Meanwhile" is referenced.

0:41 - Friday Night Funkin' song Ugh is referenced.

1:15 - What's That Sound?
Harry

Harry is the Main character of Harry and Harriot.

## Appearance

Harry is a spider with black legs. As well as Black eyes. He also has a silver body.

His prototype is Harry but drawn.

## Personality

Harry can get very nervous if there is a beautiful girl, as we saw from the first episode. He also is paranoid about being in a Tiktok/TV show.

## Trivia

* Harry was actually made by CJ's Grandad
* Harry is actually just a foil ball.
	+ His legs are made from bits of plastic.
* **Harry** is Invisible.
	+ So is Harriot.

## Reference List

1. ↑ https://youtu.be/piCq\_tBZIj4?t=3
2. ↑ https://twitter.com/EthanosSquad/status/1426577221783851009
Tankman

Tankman is Minor character in Harry and Harriot and Major character in TANKMEN.

## History

In a different shot, Tankman hit a ball, trying to score and failed to do so. It hit BadBoyHalo and Robot.

## Appearance

Tankman is a simple black and white Lego build.

## Powers

### Strong Feet

Tankman can kick a ball and injure a person, and wake up a robot by breaking its head.

## Trivia

* Tankman sings Ugh in his part.
	+ This might mean he isn't based on his TANKMEN appearance and more of his Friday Night Funkin' appearance.
	+ This also applies to Tricky as he is based more off his Friday Night Funkin' Mod rather than his Madness Combat appearance.
* He is made of Lego.

## Reference List

1. ↑ Ugh https://youtu.be/kYr9U05\_pCw?t=41
2. ↑ He says "Ugh" (Common catchphrase) https://youtu.be/m40-6JJwQhg?t=33
3. ↑ Literal part of Guns https://youtu.be/m40-6JJwQhg?t=35
4. ↑ Song: Madness (Phase 2 Tricky) https://youtu.be/m40-6JJwQhg?t=63
5. ↑ Song: Honkers (Cutscene music in between Madness and Hellclown) https://youtu.be/m40-6JJwQhg?t=69
6. ↑ People commonly mishear "Cookie" in Improbable Outset and Madness https://youtu.be/m40-6JJwQhg?t=73
7. ↑ Read above https://youtu.be/m40-6JJwQhg?t=78
8. ↑ Read above https://youtu.be/m40-6JJwQhg?t=93
9. ↑ We hear one note from Madness Tricky https://youtu.be/m40-6JJwQhg?t=112
Deneb

Deneb is a blue-white supergiant star located 2,615 light-years away from Earth in the Constellation Cygnus. It is the brightest star in the constellation and the 19th brightest star in the night sky, with an average apparent magnitude of 1.25. It is the brightest star in Cygnus and the 19th brightest star in the night sky, with an average apparent magnitude of +1.25. However, its distance, and hence luminosity, is poorly known; its luminosity is somewhere between 55,000 and 196,000 times that of the Sun. Deneb will be the North Pole star around the year 9800 AD, but as it will only come within 7° from the pole, it will not really mark true north. As the pole star, it will be preceded by Alderamin and succeeded by Fawaris. Both these stars will come within 3° of the pole. Polaris, the current North Star, is a much better indicator of true north, being located within 0.5° of the pole, but at magnitude 1.98, it is also considerably fainter than Deneb.

## Name

The name Deneb is derived from the Arabic *Dhanab al-Dajājah*, which means “the tail of the hen.” It was officially approved by the International Astronomical Union’s (IAU) Working Group on Star Names (WGSN) for Alpha Cygni on June 30, 2016. *α Cygni* (Latinized to *Alpha Cygni*) is the star's designation given by Johann Bayer in 1603.
BadBoyHalo

*Finally, head got fi- -BadBoyHalo*

BadBoyHalo is a Minor Character that is known for always getting injured, from a Ball, to Tricky.

## History

One day, he is just vibing, but then gets hit by a Ball kicked by Tankman. He also gets knocked down by Tricky.

## Trivia

* BadBoyHalo is the first character that is probably close to Death, second is Robot.
* BadBoyHalo is based off the Minecraft YouTuber of the same name, BadBoyHalo.
Ceres

Ceres is a dwarf planet between the orbits of Mars and Jupiter in the asteroid belt. It was the first asteroid discovered, on 1 January 1801, by Giuseppe Piazzi at Palermo Astronomical Observatory in Sicily. Originally considered a planet, it was re-classed as an asteroid in the 1850s. Then in 2006 it was re-classed again as a dwarf planet, the only one always inside Neptune's orbit. It is the only asteroid large enough for its gravity to maintain it as a spheroid in hydrostatic equilibrium. Ceres's small size means that even at its brightest it is still too dim to be seen by the naked eye, except under extremely dark skies. Its apparent magnitude ranges from 6.7 to 9.3, peaking at opposition (when it is closest to Earth) once every 15- to 16-month synodic period. Little was known about its surface features until the NASA spacecraft Dawn started its orbital mission in 2015. Dawn found that Ceres's surface is a mixture of hydrated minerals such as carbonates and clay. It consists of about a quarter of the mass of the asteroid belt, or 910 Quintillion Kg.
Gliese 436 b

Gliese 436 b is a Neptune sized exoplanet orbiting a red dwarf star called Gliese 436. It was the first hot-neptune to be discovered with certainty in 2007 and was among the smallest known transiting planets in mass and radius until the discovery of a much smaller Kepler planet in 2010. In December 2013, NASA reported that clouds may have been detected in the atmosphere of Gliese 436 b. One of Gliese 436b's main characteristics, even at such a high temperature, it still has ice, obviously not being an ordinary ice, but formed by compressed water at a very high pressure.

## Discovery

Gliese 436b was discovered by R. Paul Butler and Geoffrey Marcy of the Carnegie Institute of Washington and University of California, Berkeley, respectively, using the radial velocity method. Together with 55 Cancri e, it was the first of a new class of planets with a minimum mass different to Neptune.

The planet was recorded to transit its star by an automatic process at NMSU on January 11, 2005, but this event went unheeded at the time. In 2007, Michael Gillon from Geneva University in Switzerland led a team that observed the transit, grazing the stellar disc relative to Earth. Transit observations led to the determination of its exact mass and radius, both of which are very similar to that of Neptune, making Gliese 436 b at that time the smallest known transiting extrasolar planet. The planet is about four thousand kilometres larger in diameter than Uranus and five thousand kilometres larger than Neptune and slightly more massive. Gliese 436b orbits at a distance of four million kilometres, or one-fifteenth the average distance of Mercury from the Sun.
Harry and Harriot - Brick Infestation

Brick Infestation is the Second episode of the 1st Season.

## Plot

A Lego storm has happened and Harry and Harriot argue for a little bit before mentioning Steve. Harriot gets hit by Ruben as he falls from the sky and Harry makes a stupid joke. Ruben is so happy and has a conversation with Harry. Harry then gets hit with Lego after the conversation, presumably a Lego storm.

## Characters

### Main Characters

* Harry
* Harriot

### Background Character

* Steve (Debut)
* Parrot (Debut)

## Trivia

* This is the first episode include a background character.
Wasp-96b

Wasp-96b is an exoplanet located 1,120 light-years away from Earth in the constellation Phoenix. It is 0.0453 AU from the class G star WASP-96, which it orbits every 3.4 days. It was discovered in 2013 by the Wide Angle Search for Planets (WASP). WASP-96b's spectrum is one of the items featured in the initial science release from the James Webb Space Telescope. The spectrum confirmed the presence of water, as well as providing evidence for “clouds and hazes” within the planet's atmosphere. Prior to this discovery, WASP-96b was thought to be free of clouds. WASP-96b orbits its Sun-like star WASP-96 every 3.5 Earth days at a distance just one-ninth of the distance between Mercury and the Sun. While the light curve released confirms properties of the planet that had already been determined from other observations – the existence, size, and orbit of the planet – the transmission spectrum revealed previously hidden details of the atmosphere: the unambiguous signature of water, indications of haze, and evidence of clouds that were thought not to exist based on prior observations.
Sirius

Sirius is located 8.6 light-years away from Earth and is the brightest star in the night sky. Sirius is so bright it's almost twice as bright as Canopus, the next brightest star. It is a part of a binary system consisting of Sirius A and a white dwarf, Sirius B. The distance between the two varies quite a bit between 8.2AU and 31.5AU as they orbit each other every 50 years.

Sirius appears bright because of its intrinsic luminosity and its proximity to the Solar System. The Sirius system is one of Earth's nearest neighbours. Sirius is gradually moving closer to the Solar System, so it is expected to increase in brightness slightly over the next 60,000 years, reaching a peak magnitude of -1.68. After that time, its distance will begin to increase, and it will become fainter, but it will continue to be the brightest star in the Earth's night sky for approximately the next 210,000 years, before Vega, another A-type star more luminous than Sirius becomes the brightest star.

Sirius is approximately twice as massive as the Sun. It is roughly 25 times as luminous as the Sun, but has a significantly lower luminosity than other bright stars such as Canopus or Rigel. The system is between 200 and 300 million years old. It was originally composed of two bright bluish stars. The more massive of these, Sirius B, consumed its hydrogen fuel and became a red giant before shedding its outer layers and collapsing into its current state as a white dwarf around 120 million years ago.
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Pollux

Pollux is located 34 light-years away from Earth and is the brightest star in the constellation Gemini. It is classed as an Orange Giant. In 2006 a planet was confirmed to be orbiting it, it was designated the name Pollux b and later named Thestias. It is slightly fainter than Antares and Spica, and just outshines Denebola and Fomalhaut. Pollux is the nearest giant star to The Solar System. Pollux and its Neighbour Castor mark the heads of the celestial twins represented by the constellation Gemini. The two stars are about 18 light-years. Even though they are referred to as twins and appear similar in brightness, the two stars are very different. Pollux, which is slightly closer to us, is a single star, while Castor is a star system consisting of six stars. It is located about the same distance away as Arcturus.

## Name

The traditional name *Pollux* refers to the twins Castor and Pollux in Greek and Roman mythology. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included *Pollux* for this star.

Castor and Pollux are the two “heavenly twin” stars, giving the constellation Gemini (Latin, 'the twins') its name. The stars, however, are quite different in detail. Castor is a complex sextuple system of hot, bluish-white type A stars and dim red dwarfs, while Pollux is a single, cooler yellow-orange giant.

## Physical Characteristics

At an apparent visual magnitude of 1.14, Pollux is the brightest star in its constellation, even brighter than its neighbour Castor (α Geminorum). Pollux is 6.7 degrees north of the ecliptic, presently too far north to be occulted by the Moon. The last lunar occultation visible from Earth was on 30 September 116 BCE from high southern latitudes.

The star is larger than the Sun, with about two times its mass and almost nine times its radius. Once an A-type main-sequence star, Pollux has exhausted its hydrogen fuel and evolved into a giant star with a stellar classification of K0 III. The effective temperature of this star's outer envelope is about 4,666 K, which lies in the range that produces the characteristic orange hue of K-type stars. Pollux has a projected rotational velocity of 2.8 km/s. The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is uncertain, with estimates ranging from 85% to 155% of the Sun's abundance.
Tarantula Nebula

The tarantula nebula is a nebula located 160,000 light-years from Earth in the Large Magellanic Cloud. For this same reason, the Tarantula Nebula actually didn’t get its common name until more powerful photos were generated during the 20th century. These photos allowed astronomers to peer more deeply into the central structures than ever before and see the extremely hot hydrogen filaments that give this nebula its giant spider-like appearance. The Tarantula Nebula is estimated to be more than 100 times the size of the nearest such structure to Earth, the Orion Nebula. Astronomers estimate that if it was in the position the Orion Nebula now occupies, it would produce active shadow regions on Earth and take up enough cosmic space to fit 60 full Moons stacked end to end – so about half the visible sky! The Tarantula Nebula also encompasses one of the nearest documented supernova explosions, catalogued as Supernova 1987A. This supernova became famous because it could be easily viewed with the naked eye when the star exploded in 1987. The Tarantula Nebula is where the most massive catalogued stars known to humankind reside, for example, R136a1 and Melnick 42. As such, it is a frequent target for astronomy students striving to learn more about star formation in all its various life stages and aspects.

## Discovery

The Tarantula Nebula was observed by Nicolas-Louis de Lacaille during an expedition to the Cape of Good Hope between 1751 and 1753. He catalogued it as the second of the “Nebulae of the First Class”, “Nebulosities not accompanied by any star visible in the telescope of two feet”. It was described as a diffuse nebula 20' across.

Johann Bode included the Tarantula in his 1801 *Uranographia* star atlas and listed it in the accompanying *Allgemeine Beschreibung und Nachweisung der Gestirne* catalogue as number 30 in the constellation “Xiphias or Dorado”. Instead of being given a stellar magnitude, it was noted to be nebulous.

The name Tarantula Nebula arose in the mid 20th century from the appearance of deep photographic exposures.

30 Doradus has often been treated as the designation of a star, or of the central star cluster NGC 2070, but is now generally treated as referring to the whole nebula area of the Tarantula Nebula.
Dysnomia

Artist Impression of Dysnomia

Dysnomia is the seventeenth-largest moon in the Solar System and the only known moon of Eris and likely the second-largest moon of a Dwarf Planet after Charon. It was discovered in 2005 by Mike Brown and the laser guide star adaptive optics team at the W. M. Keck Observatory. The discovery of Dysnomia allowed for precise calculations of Eris mass to be made, resulting in Eris being 27% more massive than Pluto (despite being thought to be slightly smaller in diameter).

## Discovery

During 2005, the adaptive optics team at the Keck telescopes in Hawaii carried out observations of the four brightest Kuiper belt objects (Pluto, Makemake, Haumea, and Eris), using the newly commissioned laser guide star adaptive optics system. Observations taken on September 10, 2005, revealed a moon in orbit around Eris, provisionally designated S/2005 (2003 UB313) 1. In keeping with the *Xena* nickname that was already in use for Eris, the moon was nicknamed “Gabrielle” by its discoverers, after Xena's sidekick.

## Physical Characteristics

Dysnomia has an estimated diameter of 700 ± 115 km with an albedo of 0.04

−0.01. The estimate was obtained using radiometric observation by ALMA observatory in submillimeter spectral region. A wide range of potential masses for the satellite is possible, depending on its density, with a system mass ratio of anywhere from 37:1 to 115:1. Thus, Dysnomia's mass could be anywhere from 0.143×1021kg with a minimal 0.8g/cm3 density, to 0.445×1021kg if it has the same density as Eris (2.43 g/cm3, three times more). However, given the extreme difference in albedo, it is unlikely that Dysnomia is a solid body like Eris, and something toward the low end of that range is more likely.

The shape of Dysnomia is not known. It might have a spherical shape due to its large dimensions; it is larger than the three smallest ellipsoidal moons of Saturn and Uranus (Enceladus, Mimas, and Miranda). It is the 17th-largest known moon in the solar system. In its discovery images, Dysnomia was ~60 times fainter (or 4.43 magnitudes) than Eris in the K band, and later observations with the Hubble Space Telescope found it to be 500 times fainter in the visible band. This indicates a very different, and quite redder, spectrum, indicating a significantly darker surface. Of the known moons of dwarf planets, only Charon is larger than Dysnomia.
Earendel

Earendel is a star located 28 billion light-years away from Earth in the Constellation Cetus. Discovered in 2022 by the Hubble Space Telescope, it is the furthest star ever discovered. The previous farthest known star, MACS J1149 Lensed Star 1, a.k.a. Icarus, at a distance of 14.4 billion light-years, was discovered by Hubble in 2018. Stars like Earendel can be observed at cosmological distances thanks to the large magnification factors involved, that can exceed 1000. Other stars have been observed through this technique, such as Godzilla. Earendel has an extreme redshift of 6.2.

## Name

The name Earendel comes from the Old English name for “rising light” or “morning star.” The name is also a reference to Eärendil the Mariner, a half-elven character in J. R. R. Tolkien’s *The Silmarillion* (1977) and *Unfinished Tales* (1980). In Tolkien lore, Eärendil carries the last of the Silmarils (jewels composed of the light of the Two Trees), which becomes the Morning Star. The star was named by the researchers who discovered it. They explained that it was a good fit for a star that existed during the Cosmic Dawn, a period when the first stars, black holes and galaxies started to form. The period lasted from about 50 million years to one billion years after the Big Bang.
Bellatrix

Bellatrix is a blue giant star located 250 light-years away from Earth in the constellation Orion. With a slightly variable magnitude of around 1.6, it is typically the 25th-brightest star in the night sky. It is around 7.7 times as massive as the sun with 5.75 times its diameter. A 2011 study of the star’s spectrum suggested that Bellatrix was not a single star, but a spectroscopic binary system consisting of two stars with similar properties, both less luminous than a B2-type giant would be.

In 1971, Bellatrix was used as a spectral standard for the spectral class B2 III as part of an effort to create a reference frame for the classification of class O and early B stars. However, an analysis of the star’s properties has shown it to be a main sequence star (V), not a giant (III). A study published in 2004 was the first to raise a concern about the star’s spectral type being incorrect. Complicating things further, a 2011 study of the star’s spectrum recommended that Bellatrix was not a single star, but a spectroscopic binary system consisting of two stars with similar properties, both less luminous than a B2-type giant would be. If Bellatrix is in fact a double-lined spectroscopic binary star (SB2), the companion is also an early or mid B-type star.
51 Pegasi

51 Pegasi and its planet 51 Pegasi b

   51 Pegasi is a sun-like star located 50 light-years away from Earth in the constellation Pegasus. It was the first main-sequence star found to have a planet (designated 51 Pegasi b or officially named Dimidium) orbiting it. 51 Pegasi, which has physical properties (luminosity and temperature, for example) very similar to those of the Sun. The apparent magnitude of the star is 5.49, making it visible to the naked eye under ideal viewing conditions.

The chromosphere’s temperature is approximately 5,298 °C, giving 51 Pegasi the characteristic yellow hue of a G-type star. It is estimated to be 6.1 – 8.1 billion years old, slightly older than the Sun, with a 24 percent larger radius and 11 percent greater mass. The star has a higher proportion of elements other than hydrogen/helium than the Sun, which astronomers refer to as a star’s metallicity. Planets are more likely to be found in stars with higher metallicity, such as this one.

Despite the fact that the star was suspected of being variable during a 1981 study, subsequent observations revealed virtually no chromospheric activity between 1977 and 1989. A closer look between 1994 and 2007 revealed a similar low or flat level of activity. This, combined with the star’s relatively low X-ray emission, suggests that the star is in a Maunder minimum period, during which a star produces fewer star spots.
OGLE-2005-BLG-390Lb

OGLE-2005-BLG-390Lb is a Mini-Neptune located 21,500 light-years away from Earth in the constellation Scorpius. It resides quite close to the centre of the Milky Way. It is one of the furthest planets discovered, and the coldest planet discovered at only 50K or -220°C. Because of its extreme temperature, it is very likely it does not have a substantial atmosphere because any gases present will freeze on the surface. Even though it is closer to it's star than all the Gas Giants in the Solar System are to the Sun, it is still very cold, since it orbits a red dwarf star that is much smaller, colder and less massive than the Sun.

## Discovery

OGLE-2005-BLG-390Lb was discovered on the 25th of January 2006 through the Gravitational Lensing Method. Gravitational lensing occurs when light from a distant star is bent and magnified by the gravitational field of a foreground star. A *gravitational microlensing* event occurs when a planet accompanying this foreground star can cause an additional small increase in the intensity of magnified light as it passes between the background star and the observer as well. The PLANET/RoboNet campaign regularly investigates promising microlensing event alerts that are issued by the Polish OGLE or the Japanese–New Zealand MOA survey. The observation of just such an event led to the discovery of OGLE-2005-BLG-390Lb. OGLE detected the microlensing effect produced by the star OGLE-2005-BLG-390L, and it was the PLANET team's follow-up observations and analysis which uncovered evidence of the planet itself. The PLANET team conducted close observation of the OGLE-2005-BLG-390 microlensing event over a period of about two weeks. During this series of observations, a 15% “spike” in intensity occurred, lasting approximately 12 hours. From the intensity of the increase, and its length, the PLANET astronomers were able to derive the planet's mass, and its approximate displacement from the star. The paper submitted to *Nature* bears the names of all members of PLANET, RoboNet, OGLE, and MOA.
R136a1

R136a1 is a star located 163,000 light-years from Earth in the Constellation Dorado. It is the most massive and most luminous star ever discovered, at 222 Solar masses and 7.2 million sun luminosities. It is also one of the hottest at 46,000°C. Not only that, but it is a wolf-rayet star at the centre of R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula nebula in the Large Magellanic Cloud. The cluster can be seen in the far southern celestial hemisphere with binoculars or a small telescope, at magnitude 7.25. R136a1 itself is 10,000 times fainter and can only be resolved using speckle interferometry.

## Discovery

In 1960, a group of astronomers working at the Radcliffe Observatory in Pretoria made systematic measurements of the brightness and spectra of bright stars in the Large Magellanic Cloud. Among the objects catalogued was RMC 136 (Radcliffe observatory Magellanic Cloud catalogue number 136), the central “star” of the Tarantula Nebula, which the observers concluded was probably a multiple star system. Subsequent observations showed that R136 was located in the middle of a giant region of ionized interstellar hydrogen, known as an H II region, which was a centre of intense star formation in the immediate vicinity of the observed stars.

In 1979, ESO's 3.6 m telescope was used to resolve R136 into three components; R136a, R136b, and R136c. The exact nature of R136a was unclear and a subject of intense discussion. Estimates that the brightness of the central region would require as many as 100 hot O class stars within half a parsec at the centre of the cluster led to speculation that a star 3,000 times the mass of the Sun was the more likely explanation.

The first demonstration that R136a was a star cluster was provided by Weigelt and Beier in 1985. Using the speckle interferometry technique, R136a was shown to be made up of 8 stars within 1 arcsecond at the centre of the cluster, with R136a1 being the brightest.

Final confirmation of the nature of R136a came after the launch of the Hubble Space Telescope. Its Wide Field and Planetary Camera (WFPC) resolved R136a into at least 12 components and showed that R136 contained over 200 highly luminous stars. The more advanced WFPC2 allowed the study of 46 massive luminous stars within half a parsec of R136a and over 3,000 stars within a 4.7 parsec radius.
Rhea

Rhea is the second-largest moon of Saturn and the ninth-largest moon in the Solar System. It is the smallest body in the Solar System for which precise measurements have confirmed a shape consistent with hydrostatic equilibrium. It was discovered in 1672 by Giovanni Domenico Cassini. Rhea was the second moon of Saturn that Cassini discovered, and the third moon discovered around Saturn overall.

Rhea is an icy body with a density of about 1.236 g/cm3. This low density indicates that it is made of ~25% rock (density ~3.25 g/cm3) and ~75% water ice (density ~0.93 g/cm3). Although Rhea is the ninth-largest moon, it is only the tenth-most massive moon. Indeed, Oberon, the second-largest moon of Uranus, has almost the same size, but is significantly denser than Rhea (1.63 vs 1.24) and thus more massive, although Rhea is slightly larger by volume.

Before the Cassini-Huygens mission, it was assumed that Rhea had a rocky core. However, measurements taken during a close flyby by the Cassini orbiter in 2005 cast this into doubt. In a paper published in 2007 it was claimed that the axial dimensionless moment of inertia coefficient was 0.4.

Rhea's features resemble those of Dione, with dissimilar leading and trailing hemispheres, suggesting similar composition and histories. The temperature on Rhea is −174 °C in direct sunlight and between −200 °C and −220 °C in the shade. Rhea has a rather typical heavily cratered surface, with the exceptions of a few large Dione-type chasmata or fractures (wispy terrain) on the trailing hemisphere (the side facing away from the direction of motion along Rhea's orbit) and a very faint “line” of material at Rhea's equator that may have been deposited by material deorbiting from its rings. Rhea has two very large impact basins on its anti-Cronian hemisphere (facing away from Saturn), which are about 400 and 500 km across. The more northerly and less degraded of the two, called Tirawa, is roughly comparable to the basin Odysseus on Tethys. There is a 48 km-diameter impact crater at 112°W that is prominent because of an extended system of bright rays. This crater, called Inktomi, is nicknamed “The Splat”, and may be one of the youngest craters on the inner moons of Saturn. No evidence of any endogenic activity has been discovered.
Ganymede

Ganymede is the largest Satellite of Jupiter and the largest in the Solar System (even larger than Mercury)! It is the ninth-largest object in the solar system. Not only that, but Ganymede is the largest body in the solar system with no substantial atmosphere and is the only confirmed moon to have a magnetic field. Ganymede orbits Jupiter in roughly seven days and is the 7th planet outward from Jupiter.

Ganymede is composed of approximately equal amounts of silicate rock and water. It has an internal ocean like Europa with more water than all the water on Earth.

Ganymede's magnetic field is most likely caused by convection in its liquid core, but since it's magnetic field resides within Jupiter's, it will only look like a local perturbation in the field lines.

Ganymede's discovery is credited to Galileo Galilei, who observed it in January 7th 1610. There have been many spacecraft which visited Ganymede. The first of them was Pioneer 10 which made a fly-by of Jupiter and was the first out of 5 spacecraft to achieve the escape velocity needed to leave the Solar System. Then came Voyager 1 and Voyager 2 which refined measurements of the size of Ganymede. Galileo (the spacecraft) discovered the magnetic field and underground ocean. The next planned mission is the ESA's Jupiter Icy Moon Explorer (JUICE), due to launch in 2023. After flybys of all three icy Galilean moons, it is planned to enter orbit around Ganymede.
HD 189733b

HD 189733b is an exoplanet located 64.5 light-years away from Earth in the constellation Vulpecula. Astronomers in France discovered the planet orbiting the star HD 189733 on October 5, 2005, by observing its transit across the star's face. It orbits very close to its star at 0.03 AU. It orbits the star every 2.2 days with an orbital speed of 152.5km/s making it a hot Jupiter. The closest transiting hot Jupiter to Earth, HD 189733 b is a subject of extensive atmospheric examination. Accordingly, scientists have extensively studied the exoplanet's atmosphere with high- and low-resolution instruments, both from the ground and space. As a result, HD 189733 b was the first exoplanet to have its thermal map constructed (possibly to be detected through polarimetry), its overall colour determined (deep blue), transit in the X-ray spectrum, and carbon dioxide confirmed in its atmosphere. In July 2014, NASA announced finding very dry atmospheres on three exoplanets (HD 189733b, HD 209458b, WASP-12b) orbiting Sun-like stars.

## Discovery

On October 6, 2005, a team of astronomers announced the discovery of transiting planet HD 189733 b. The planet was then detected using Doppler spectroscopy. Real-time radial velocity measurements detected the Rossiter–McLaughlin effect caused by the planet passing in front of its star, before photometric measurements confirmed that the planet was transiting. In 2006, a team led by Drake Deming announced detection of strong infrared thermal emission from the transiting exoplanet planet HD 189733b, by measuring the flux decrement (decrease of total light) during its prominent secondary eclipse (when the planet passes behind the star).

The mass of the planet is estimated to be 16% larger than Jupiter's, with the planet completing an orbit around its host star every 2.2 days and an orbital speed of 152.5 kilometres per second (94.72miles a second).
Rigel

Rigel is a blue Supergiant star in the constellation Orion. It's the 7th brightest star in the night sky. It is about 80 times bigger than the Sun and 21 times more massive. Rigel is 8 million years old and will go type II Supernova and, leaving behind a Neutron Star or a Black Hole as a final Remnant. It's the most massive and brightest of a star system of at least 4 stars that appear as a single blue, white dot to the naked eye. It can be calculated as anywhere between 61,500 to 300,000 times as luminous as the sun. Due to its stellar wind, Rigel's mass-loss is estimated to be ten million times that of the Sun. Rigel has exhausted its core hydrogen fuel, expanded, and cooled to become a supergiant. It varies in brightness from time to time from having an apparent magnitude 0f 0.05 to 0.18. Because of this, it is occasionally outshone by Betelgeuse.

A triple-star system is separated from Rigel by an angle of 9.5 arc seconds. It has an apparent magnitude of 6.7, making it 1/400th as bright as Rigel. Two stars in the system can be seen by large telescopes, and the brighter of the two is a spectroscopic binary. These three stars are all blue-white main-sequence stars, each three to four times as massive as the Sun. Rigel and the triple system orbit a common centre of gravity with a period estimated to be 24,000 years. The inner stars of the triple system orbit each other every 10 days, and the outer star orbits the inner pair every 63 years. A much fainter star, separated from Rigel and the others by nearly an arc minute, may be part of the same star system.
Callisto

Callisto is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's moon Titan, and the largest object in the Solar System that may not be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. With a diameter of 4820 km, Callisto is about 99% the diameter of Mercury, but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about 1,883,000km. It is not in an orbital resonance like the three other Galilean satellites—Io, Europa, and Ganymede—and is thus not appreciably tidally heated. Callisto's rotation is tidally locked to its orbit around Jupiter, so that the same hemisphere always faces inward. Because of this, there is a sub-Jovian point on Callisto's surface, from which Jupiter would appear to hang directly overhead. It is less affected by Jupiter's magnetosphere than the other inner satellites because of its more remote orbit, located just outside Jupiter's main radiation belt.

Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3, the lowest density and surface gravity of Jupiter's major moons. Compounds detected spectroscopically on the surface include water ice, carbon dioxide, silicates, and organic compounds. Investigation by the Galileo spacecraft revealed that Callisto may have a small silicate core and possibly a subsurface ocean of liquid water at depths greater than 100 km.

The surface of Callisto is the oldest and most heavily cratered in the Solar System. Its surface is completely covered with impact craters. It does not show any signatures of subsurface processes such as plate tectonics or volcanism, with no signs that geological activity in general has ever occurred, and is thought to have evolved predominantly under the influence of impacts.

Callisto is surrounded by an extremely thin atmosphere composed of carbon dioxide and probably molecular oxygen, as well as by a rather intense ionosphere. Callisto is thought to have formed by slow accretion from the disk of the gas and dust that surrounded Jupiter after its formation. Its gradual accretion and the lack of tidal heating meant that not enough heat was available for rapid differentiation. The slow convection in the interior of Callisto, which commenced soon after formation, led to partial differentiation and possibly to the formation of a subsurface ocean at a depth of 100–150 km and a small, rocky core.

The likely presence of an ocean within Callisto leaves open the possibility that it could harbour life. However, conditions are thought to be less favourable than on nearby Europa. Various space probes from Pioneers 10 and 11 to Galileo and Cassini have studied Callisto. Because of its low radiation levels, Callisto has long been considered the most suitable place for a human base for future exploration of the Jovian system.
Ariel

Ariel compared to Earth and The Moon

Ariel is the fourth-largest moon of Uranus. It was discovered on October 24th 1851 and named for a character in two different pieces of literature. It was discovered at the same time as Umbriel. Ariel orbits and rotates in the equatorial plane of Uranus, which is almost perpendicular to the orbit of Uranus and so has an extreme seasonal cycle.

As of 2019, much of the detailed knowledge of Ariel derives from a single flyby of Uranus performed by the space probe *Voyager 2* in 1986, which managed to image around 35% of the moon's surface. There are no active plans at present to return to study the moon in more detail, although various concepts such as a Uranus orbiter and probe have been proposed.

After Miranda, Ariel is the second-smallest of Uranus's five major rounded satellites and the second-closest to its planet. Among the smallest of the Solar System's 19 known spherical moons (it ranks 14th among them in diameter), it is believed to be composed of roughly equal parts ice and rocky material. Its mass is approximately equal in magnitude to Earth's hydrosphere.

Like all of Uranus's moons, Ariel probably formed from an accretion disc that surrounded the planet shortly after its formation, and, like other large moons, it is likely differentiated, with an inner core of rock surrounded by a mantle of ice. Ariel has a complex surface consisting of extensive cratered terrain cross-cut by a system of scarps, canyons, and ridges. The surface shows signs of more recent geological activity than other Uranian moons, most likely due to tidal heating.
Gliese 581 c

Gliese 581c is a super-earth exoplanet 20.37 light-years away from Earth in the constellation Libra. It was the second discovered planet in that system and the third in order from its star. Gliese 581c gained interest from astronomers because it was reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and, by extension, potentially capable of supporting extremophile forms of Earth-like life. While early research suggested that Gliese 581c may have liquid water on its surface because it resides in its star's habitable zone, more recent research suggests it may have a Venus-like environment. However, further research revealed that it is tidally locked to its star, meaning the only place that life could survive is the twilight area between the Day side and the night side. In astronomical terms, the Gliese 581 system is relatively close to Earth, at 20.37 light-years.

## Discovery

The team released a paper of their findings dated 27 April 2007, published in the July 2007 journal *Astronomy & Astrophysics*. At the time of discovery, it was reported to be the first potentially Earth-like planet in the habitable zone of its star and the smallest-known extrasolar planet around a main-sequence star but on 21 April 2009, another planet orbiting Gliese 581, Gliese 581e, with an approximate mass of 1.9 Earth masses, was announced. In the paper, they also announced the discovery of another planet in the system, Gliese 581d, with a minimum mass of 7.7 Earth masses and a semi-major axis of 0.25 AU.