Hubble Probes Goldilocks Stars: Astronomers used the NASA/ESA Hubble Space Telescope to investigate the history of the massive Sombrero galaxy (M104), resolving tens of thousands of individual stars in the galaxy’s vast halo, and measuring their metallicity — the presence of heavy elements — which can provide forensic clues to the galaxy’s origin. On the left is an image of the entire galaxy that includes a portion of the much fainter halo far outside its bright disk and bulge. Hubble photographed two regions in the halo (one of which is shown by the white box). The images on the right zoom in to show the level of detail Hubble captured. The yellow box, a small subset of Hubble’s view, contains myriad halo stars. The stellar population increases in density closer to the galaxy’s disk (bottom blue box). Each frame contains a bright globular cluster of stars, of which there are many in the Sombrero’s halo. The data gathered by Hubble surprised scientists, upending expectations set by the halos of other massive galaxies. The Sombrero’s halo contained more metal-rich stars than expected, but even stranger was the near-absence of old, metal-poor stars typically found in the halos of massive galaxies. Many of the globular clusters, however, contain metal-poor stars — why were they there, but not in the broader halo? Typically, stars migrate away from their parent clusters as they age. A possible explanation for the Sombrero’s perplexing features is that it is the product of the merger of massive galaxies billions of years ago, even though the smooth appearance of the galaxy’s disk and halo show no signs of such a huge disruption.

Name: Sombrero Galaxy
Type: Local Universe : Galaxy : Type : Lenticular
Category: Galaxies
Distance: 28 million light years
Release date: 24 February 2020, 11:05
Credit: NASA, ESA, Digital Sky Survey, and P. Goudfrooij (STScI)

Hubble Probes Quasar Tsunamis Rip Across Galaxies: This is an artist's concept of a distant galaxy with an active quasar at its center. A quasar emits exceptionally large amounts of energy generated by a supermassive black hole fueled by infalling matter. Using the unique capabilities of the NASA/ESA Hubble Space Telescope, astronomers have discovered that blistering radiation pressure from the vicinity of the black hole pushes material away from the galaxy's center at a fraction of the speed of light. The "quasar winds" are propelling hundreds of solar masses of material each year. This affects the entire galaxy as the material forces itself into surrounding gas and dust.

Type: Early Universe : Galaxy : Activity : AGN : Quasar
Category: Quasars and Black Holes
Release date: 25 March 2020, 13:08
Credit: NASA, ESA, and J. Olmsted (STScI)

Hubble Probes Exoplanet WASP-79b (Artist’s Impression): The NASA/ESA Hubble Space Telescope’s data was used to analyze the atmosphere of the super-hot exoplanet WASP-79b, located 780 light-years away in the constellation Eridanus. Among exoplanets, WASP-79b is among the largest ever observed. The planet is larger than Jupiter, and its very deep, hazy atmosphere sizzles at 1,650 degrees Celsius – the temperature of molten glass. The Hubble Space Telescope and other observatories measured how starlight is filtered through the planet's atmosphere, allowing for its chemical composition to be analyzed. Hubble has detected the presence of water vapor. The surprise in recently published results, is that the planet's sky doesn't have any evidence for an atmospheric phenomenon called Rayleigh scattering, where certain colors of light are dispersed by very fine dust particles in the upper atmosphere. Rayleigh scattering is what makes Earth's skies blue by scattering the shorter (bluer) wavelengths of sunlight. Because WASP-79b doesn't seem to have this phenomenon, the daytime sky would likely be yellowish, researchers say. Link:

Name: WASP-79b
Type: Milky Way : Star : Circumstellar Material : Planetary System
Category: Exoplanets
Distance: 800 light years
Release date: 5 May 2020, 09:50
Credit: NASA, ESA, and L. Hustak (STScI)

Luhman 16A (Artist’s Impression): Astronomers have found evidence for a striped pattern of clouds on the brown dwarf called Luhman 16A, as illustrated here in this artist's impression. The bands of clouds were inferred using a technique called polarimetry, in which polarized light is measured from an astrophysical object much like polarized sunglasses are used to block out glare. This is the first time that polarimetry has been used to measure cloud patterns on a brown dwarf. The red object in the background is Luhman 16B, the partner brown dwarf to Luhman 16A. Together, this pair is the closest brown dwarf system to Earth at 6.5 light-years away.

Name: Luhman 16A
Type: Milky Way : Star : Type : Brown Dwarf
Category: Stars
Distance: 6 light years
Release date: 12 May 2020, 16:23
Credit: Caltech/R. Hurt (IPAC)