GJ 625 b

The planet GJ 625 b, orbits around an M dwarf star called GJ 625 located about 21.2 light-years from Earth. It is thought to be at least 2.8 times the mass of Earth and orbits its host star in about 14.6 days. The findings,  led by the Canary Islands Institute of Astrophysics, will be published in the Journal of Astronomy and Astrophysics.

GJ 625 b is located on the inner edge of the habitable zone, where temperatures are just right for liquid water to exist. It orbits at a distance of about 0.08 AU (astronomical units, 1 AU is the distance from Earth to the Sun).

“GJ 625 b is a small super-Earth in the habitable zone of a nearby M-dwarf,” lead author Alejandro Suarez Mascareño, from the Canary Islands Institute of Astrophysics, told IFLScience. “Even after the last round of discoveries of small exoplanets around M-dwarfs, the number of rocky planets known around this kind of star is relatively small.”

Journal Articles:

1.) HADES RV Programme with HARPS-N at TNG V. A super-Earth on the inner edge of the habitable zone of the nearby M-dwarf GJ 625

2.) Equilibrium Temperatures and Albedos of Habitable Earth-Like Planets in a Coupled Atmosphere-Ocean GCM

WEB Articles:

1.) Super-Earth Discovered Around Nearby Red Dwarf Star

2.) A new Super-Earth discovered near the habitable zone of a cool star.

CoRoT 10 b

(Imaginary Image of Corot 10b　Ryusuke Kuroki, Fuka Takagi, and Yosuke A. Yamashiki)

COROT-10b is an enormous exoplanet discovered in 2007 (reported in 2010) by the CoRoT satellite (this satellite preceded the Kepler Space Telescope in searching for planets using the transit method) after 142 days of observation. The planet has a radius of about 0.97 that of Jupiter and orbits its host star, COROT-10, in about 13.4 days. COROT-10 is a K1-type star with a surface temperature of 5075 K. It is slightly smaller in mass and radius (0.89 times the mass and 0.79 times the radius) than the Sun.

The orbital eccentricity of this planet is very large at 0.53 ± 0.04, and its orbit is elliptical, not a perfect circle. It of great interest to understand how such a large planet with such a large orbital eccentricity could exist within our knowledge of the planetary formation process.

(Yuta Notsu)

Journal Articles:

1.) Transiting exoplanets from the CoRoT space mission X. CoRoT-10b: a giant planet in a 13.24 day eccentric orbit

WEB Articles:

1.) CoRoT-10 b

2.) Planet CoRoT-10 b

CoRoT 3 b

COROT-exo-3b fits into the category of a failed star known as a brown dwarf, but the team that made the discovery has not ruled out the possibility that it is a planet. Brown dwarfs are failed stars. They burn lithium but are not massive enough to generate the thermonuclear fusion of hydrogen and helium that powers real stars. Planets do none of that.

The object has a mass 20 times greater than that of Jupiter but is roughly the same size. It falls outside the range of planets and stars discovered to date, with the largest planets having 12-Jupiter-mass and the smallest stars 70-Jupiter-mass.

If astronomers confirm the object as a planet, it would weigh in as the most massive and densest planet found so far. A full study will be detailed in the journal Astronomy and Astrophysics.

“COROT-exo-3b might turn out to be a rare object found by sheer luck”, said Francois Bouchy, an astronomer at the Institut d’Astrophysique in Paris. “But it might just be a member of a new-found family of very massive planets that encircle stars more massive than our sun. We’re now beginning to think that the more massive the star, the more massive the planet.”

The host star CoRoT 3 has an apparent magnitude of 13.3, with an absolute magnitude of 4.14. It is 1.41 times more massive and 1.44 times bigger compared with our sun. The surface temperature is 6558 K with its spectral type of F3V. In this planetary system, the extrasolar planet CoRoT 3 b orbits around the star CoRoT 3 with its orbital distance of 0.0570.

Paper:

https://www.aanda.org/10.1051/0004-6361:200810625

Journal Articles:

1.) The Rossiter-McLaughlin effect of CoRoT-3b and HD 189733b

2.) Transiting exoplanets from the CoRoT space mission, VI. CoRoT-Exo-3b: the first secure inhabitant of the brown-dwarf desert

3.) CoRoT’s first seven planets: An overview

WEB Articles:

1.) Huge Planet Defies Explanation

2.) 系外惑星の分類に疑問投げかける天体を発見