Kepler-13Ab (artist’s impression): This artist’s impression shows the seething hot planet Kepler-13Ab that circles very close to its host star, Kepler-13A. Seen in the background is the star's binary companion, Kepler-13B, and the third member of the multiple-star system is the orange dwarf star Kepler-13C. The exoplanet is classified as a hot Jupiter but is actually six times more massive than Jupiter. Unlike chilly Jupiter, this exoplanet is one of the hottest known of the hot Jupiters, with a dayside temperature of more than 2700 °C. Another difference between Jupiter and Kepler-13Ab is that the exoplanet is so close to its star that it is tidally locked. One side keeps a permanent face to the star, and the other side is perpetually dark. On the nighttime side the planet's immense gravity pulls down titanium oxide and precipitates as snow. Observations of the planet's atmospheric temperature profile made with the NASA/ESA Hubble Space Telescope represent the first time astronomers have detected this precipitation process, called a "cold trap," on an exoplanet. Without titanium oxide to absorb incoming starlight on the daytime side, the atmospheric temperature grows colder with increasing altitude. Normally, titanium oxide in the atmospheres of hot Jupiters absorbs light and reradiates it as heat, making the atmosphere grow warmer at higher altitudes. The Kepler-13 system is 1730 light-years from Earth. The research teams consists of Thomas Beatty, Ming Zhao, Jason Wright, and Ronald Gilliland (Pennsylvania State University, University Park), Nikku Madhusudhan (University of Cambridge, U.K.), Angelos Tsiaras (University College London, U.K.), and Avi Shporer and Heather Knutson (California Institute of Technology, Pasadena, California).

Name: Kepler-13Ab
Type: Milky Way : Star : Circumstellar Material : Planetary System
Category: Exoplanets
Distance: 1700 light years
Release date: 27 October 2017, 15:04
Credit: NASA, ESA, and G. Bacon (STScI)

Comparison of Kepler-13Ab with five planets from our Solar System: This is an artist’s impression of the exoplanet Kepler-13Ab as compared in size to several of the planets in the Solar System. The behemoth exoplanet is six times more massive than Jupiter. Kepler-13Ab is also one of the hottest known planets, with a dayside temperature of about 2700 °C. It orbits very close to the star Kepler-13A, which lies at a distance of 1730 light-years from Earth.

Name: Kepler-13Ab
Type: Milky Way : Star : Circumstellar Material : Planetary System
Category: Exoplanets
Distance: 1700 light years
Release date: 27 October 2017, 15:04
Credit: NASA, ESA, and A. Feild (STScI)

Distant active comet C/2017 K2: This Hubble Space Telescope image shows a fuzzy cloud of dust, called a coma, surrounding the comet C/2017 K2 PANSTARRS (K2), the farthest active comet ever observed entering the solar system. Hubble snapped images of K2 when the frozen visitor was over 2.4 billion kilometres from the Sun, just beyond Saturn's orbit. Even at that remote distance, sunlight is warming the frigid comet, producing a 128,000-kilometre-wide coma that envelops a tiny, solid nucleus. K2 has been traveling for millions of years from its home in the Oort Cloud, a spherical region at the edge of our solar system. This frigid area contains hundreds of billions of comets, the icy leftovers from the formation of the solar system 4.6 billion years ago. The image was taken in June 2017 by Hubble's Wide Field Camera 3.

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