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…
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. Links: NASA press release Kepler-13Ab (artist’s impression)
This artist’s impression shows the exoplanet WASP-12b — an alien world as black as fresh asphalt, orbiting a star like our Sun. Scientists were able to measure its albedo: the amount of light the planet reflects. The results showed that the planet is extremely dark at optical wavelengths.
A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres.
This artist’s impression shows the view from the surface of one of the planets in the TRAPPIST-1 system. At least seven planets orbit this ultracool dwarf star 40 light-years from Earth and they are all roughly the same size as the Earth. Several of the planets are at the right distances from their star for liquid water to exist on the surfaces. This artist’s impression is based on the known physical parameters of the planets and stars seen, and uses a vast database of objects in the Universe.
This picture shows the Sun and the ultracool dwarf star TRAPPIST-1 to scale. The faint star has only 11% of the diameter of the sun and is much redder in colour. As the planets found around TRAPPIST-1 orbit much closer to their star than Mercury is to the Sun, they are exposed to similar levels of radiation as Venus, Earth and Mars in the Solar System.
This is an artist’s impression of the TRAPPIST-1 system, showcasing all seven planets in various phases. When a planet transits across the disk of the red dwarf host star, as two of the planets here are shown to do, it creates a dip in the star’s light that can be detected from Earth. Also during such transits astronomers are able to study the potential atmospheres of these planets.
This diagram presents evidence for the existence of a stratosphere on a planet orbiting another star. As on Earth, the stratosphere increases in temperature with altitude. The water emissions from the Jupiter-sized planet's upper atmosphere show this. The results are in marked contrast to the spectrum of a failed star, a brown dwarf, which shows water absorption because the atmosphere is cooling with altitude increase. Links: NASA Press Release Artist's impression of WASP-121b
This is an artist’s impression of the gas giant exoplanet WASP-121b. The bloated planet is so close to its star that the tidal pull of the star stretches it into an egg shape. The top of the planet's atmosphere is heated to a blazing 2500 degrees Celsius, hot enough to boil iron. This is the first planet outside our Solar System where astronomers have found the strongest evidence yet for a stratosphere — a layer of atmosphere in which temperature increases with higher altitudes. The planet is about 900 light-years away. Links: NASA Press Release Comparison of WASP-121b stratosphere with brown dwarf atmosphere