An international team of astronomers has discovered a warm giant exoplanet orbiting the bright star TOI-677.
An artist’s impression of the warm Jupiter TOI-677b and its host star. Image credit: Sci-News.com.
“Warm giants, loosely defined as systems with periods over 10 days, are close enough to the star that they are likely to have undergone significant migration, but not as close that tidal effects can erase the potential imprints of that migration,” said Dr. Andres Jordan of the Universidad Adolfo Ibanez and Millennium Institute for Astrophysics and his colleagues.
“In the same vein, they are far enough from their parent star that their radii have not been inflated by the mechanism that acts to bloat the radii of hotter giants.”
“But while it is clear that these systems are very interesting, the population of known warm giants around nearby stars (allowing the most detailed characterization) is still very small.”
Designated TOI-677b, the new warm giant was detected by NASA’s Transiting Exoplanet Survey Satellite (TESS).
“We followed up the host star, TOI-677, with several spectrographs in order to confirm the TESS transiting planet candidate and to measure its mass,” the astronomers explained.
They found that TOI-677b is approximately 1.2 times larger and more massive than Jupiter.
“Its radius is in line with what is expected for a gas giant with a core of 10 Earth masses according to the standard models,” they said.
The F-type star TOI-677 (bright star in the center). Image credit: Centre de Données astronomiques de Strasbourg / SIMBAD / DECam Plane Survey.
TOI-677 is an F-type star that is approximately 464 light-years away from Earth.
Also known as HD 297549 and 2MASS J09362869-5027478, this star is slightly bigger and more massive than the Sun, and is about 2.92 billion years old.
TOI-677b orbits the star with an orbital period of 11.24 days on an eccentric orbit.
“With an eccentricity of 0.435, it lies in the upper range of eccentricity values for planets with similar periods in the currently known sample,” Dr. Jordan and co-authors said.
A paper detailing the discovery will be published in a journal of the American Astronomical Society.
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Andrés Jordán et al. 2019. TOI-677 b: A Warm Jupiter (P=11.2d) on an eccentric orbit transiting a late F-type star. arXiv: 1911.05574
