Schematic of comet C/2017 K2's approach to the Solar System: This illustration shows the orbit of comet C/2017 K2 PANSTARRS (K2) on its maiden voyage into the solar system. The Hubble Space Telescope observed K2 when it was over 2.4 billion kilometres from the Sun, halfway between the orbits of Saturn and Uranus. The observations revealed a fuzzy cloud of dust, called a coma, surrounding the icy visitor, evidence that the frozen comet is being warmed by the Sun and releasing material. K2 is the farthest active inbound comet ever observed. K2 has been traveling toward the Sun for millions of years from its home in the Oort Cloud, a spherical region at the edge of our solar system. The graphic shows the comet in its inbound journey, high above the plane of the major planets' orbits. The orbits of the giant planets, from Jupiter to Neptune, are also shown in the diagram. The farthest object from the Sun depicted here is the dwarf planet Pluto, which resides in the Kuiper Belt, a vast rim of primordial debris encircling our solar system.

Name: C/2017 K2 PANSTARRS
Type: Solar System : Interplanetary Body : Comet
Category: Solar System
Release date: 2 October 2017, 12:28
Credit: NASA, ESA, and A. Feild (STScI)

Light Echo around SN 2014J in M82: Light from a supernova explosion in the nearby starburst galaxy Messier 82 is reverberating off a huge dust cloud in interstellar space. The supernova, called SN 2014J, occurred at the upper right of Messier 82, and is marked by an “X.” The supernova was discovered on 21 January 2014. The inset images at the top reveal an expanding shell of light from the stellar explosion sweeping through interstellar space, called a “light echo.” The images were taken 10 months to nearly two years after the violent event (6 November 2014 to 12 October 2016). The light is bouncing off a giant dust cloud that extends 300 to 1600 light-years from the supernova and is being reflected toward Earth. SN 2014J is classified as a Type Ia supernova and is the closest such blast in at least four decades. A Type Ia supernova occurs in a binary star system consisting of a burned-out white dwarf and a companion star. The white dwarf explodes after the companion dumps too much material onto it. The image of Messier 82 reveals a bright blue disc, webs of shredded clouds, and fiery-looking plumes of glowing hydrogen blasting out of its central regions. Close encounters with its larger neighbor, the spiral galaxy Messier 81, is compressing gas in Messier 82 and stoking the birth of multiple star clusters. Some of these stars live for only a short time and die in cataclysmic supernova blasts, as shown by SN 2014J. Located about 11 million light-years away, Messier 82 appears high in the constellation Ursa Major, the Great Bear. It is also called the “Cigar Galaxy” because of the elliptical shape produced by the oblique tilt of its starry disk relative to our line of sight. The Messier 82 image was taken in 2006 using the Advanced Camera for Surveys. The inset images of the light echo also were taken by the Advanced Camera for Surveys.

Name: SN 2014J
Type: Local Universe : Nebula : Appearance : Reflection : Light Echo
Category: Nebulae
Distance: 11 million light years
Release date: 14 November 2017, 10:52
Credit: NASA, ESA, and Y. Yang (Texas A&M University and Weizmann Institute of Science, Israel) Acknowledgment: M. Mountain (AURA) and The Hubble Heritage Team (STScI/AURA)

Hubble captures glittering crowded hub of our Milky Way: This image from the NASA/ESA Hubble Space Telescope shows a sparkling jewel box full of stars captured the heart of our Milky Way. Aging red giant stars coexist with their more plentiful younger cousins, the smaller, white, Sun-like stars, in this crowded region of our galaxy’s ancient central hub, or bulge. Most of the bright blue stars in the image are probably recently formed stars located in the foreground, in the galaxy's disc. Astronomers studied 10 000 of these Sun-like stars in archival Hubble images over a nine-year period to unearth clues to our galaxy’s evolution. The study reveals that the Milky Way’s bulge is a dynamic environment of variously aged stars zipping around at different speeds, like travelers bustling about a busy airport. The researchers found that the motions of bulge stars are different, depending on a star’s chemical composition. Stars richer in elements heavier than hydrogen and helium have less disordered motions, but are orbiting around the galactic centre faster than older stars that are deficient in heavier elements. The image is a composite of exposures taken in near-infrared and visible light with Hubble’s Wide Field Camera 3. The observations are part of two Hubble surveys: the Galactic Bulge Treasury Program and the Sagittarius Window Eclipsing Extrasolar Planet Search. The centre of our galaxy is about 26 000 light-years away.

Type: Milky Way : Star
Category: Stars
Constellation: Sagittarius
Distance: 25000 light years
Release date: 12 January 2018, 13:40
Credit: NASA, ESA, and T. Brown (STScI), W. Clarkson (University of Michigan-Dearborn), and A. Calamida and K. Sahu (STScI)

View of the heart of our Milky Way from Earth: The vast edge-on stretch of our home galaxy, the Milky Way, is seen intersecting the night sky above the silhouetted Rocky Mountains in this photograph. The Milky Way noticeably widens at lower right. This wider area is the central hub, or bulge, of our galaxy. Peering into a very narrow region of the core, astronomers used the NASA/ESA Hubble Space Telescope to study the compositions and motions of 10 000 Sun-like stars, as seen in the inset Hubble image. The analysis reveals that our galaxy's bulge is an unexpectedly dynamic environment of stars of various ages zipping around at different speeds, like travelers bustling about a busy airport. The study yields important new clues to the complexity of the central bulge and our Milky Way's evolution over billions of years. The Hubble image is a composite of exposures taken in near-infrared and visible light with Hubble's Wide Field Camera 3. The observations are part of two Hubble surveys: the Galactic Bulge Treasury Program and the Sagittarius Window Eclipsing Extrasolar Planet Search. The centre of our galaxy is about 26 000 light-years away.

Name: Milky Way
Type: Milky Way : Star
Category: Stars
Distance: 25000 light years
Release date: 12 January 2018, 13:41
Credit: NASA, ESA, and Z. Levay (STScI)

Stretched out image of distant galaxy: This is an image from the NASA/ESA Hubble Space Telescope of the farthest galaxy yet seen in an image that has been stretched and amplified by a phenomenon called gravitational lensing. The embryonic galaxy, named SPT0615-JD, existed when the Universe was just 500 million years old. Though a few other primitive galaxies have been seen at this early epoch, they have essentially all looked like red dots, given their small size and tremendous distances. However, in this case, the gravitational field of a massive foreground galaxy cluster, called SPT-CL J0615-5746, not only amplified the light from the background galaxy but also smeared the image of it into an arc (about 2 arcseconds long). Image analysis shows that the galaxy weighs in at no more than 3 billion solar masses (roughly 1/100th the mass of our Milky Way galaxy). It is less than 2500 light-years across, half the size of the Small Magellanic Cloud, a satellite galaxy of the Milky Way. The object is considered prototypical of young galaxies that emerged during the epoch shortly after the Big Bang.

Name: SPT0615-JD, SPT-CL J0615-5746
Type: Early Universe : Galaxy : Grouping : ClusterEarly Universe : Galaxy : Type : Gravitationally LensedEarly Universe : Cosmology : Phenomenon : Lensing
Category: CosmologyGalaxies
Distance: 8 billion light years
Release date: 12 January 2018, 13:45
Credit: NASA , ESA, and B. Salmon (STScI)