A puffy gas giant slightly larger than Jupiter has been discovered orbiting the early M-type dwarf star TOI-1899, thanks to new data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and the Habitable-zone Planet Finder (HPF) on the 10-m Hobby-Eberly Telescope at McDonald Observatory.
An artist’s impression of the warm-Jupiter exoplanet TOI-1899b and the red dwarf TOI-1899, the lowest-mass star known to host a transiting warm Jupiter. Image credit: Sci-News.com.
TOI-1899 is an M0-type star located 419 light-years away in the constellation of Cygnus.
Also known as TIC 172370679 and 2MASS 19574239+4008357, the star has a temperature of 3,652 degrees Celsius and is much cooler than the Sun.
TOI-1899 is about 60% the size and mass of the Sun and is around 7.4 billion years old.
The newfound planet orbits the star once every 29 days at a distance of only 0.16 AU.
Designated TOI-1899b, the alien world is two-thirds the mass of Jupiter but 10% larger in radius.
“Warm Jupiters like TOI-1899b orbit surprisingly close to their star,” said co-author Dr. Rebekah Dawson, an astronomer in the Department of Astronomy and Astrophysics and the Center for Exoplanets and Habitable Worlds at the Pennsylvania State University.
“Even though the planet’s orbital period is long compared to many other giant planets detected and characterized through the transit method, it still places the giant planet much closer to its star than we’d expect from classical formation theories.”
“This is only the fifth Jupiter-sized planet transiting a low-mass star that has been observed and the first with such a long orbital period, which makes this discovery really exciting,” said lead author Caleb Cañas, a Ph.D. student in the Department of Astronomy and Astrophysics and the Center for Exoplanets and Habitable Worlds at the Pennsylvania State University.
TOI-1899b was detected by TESS using the transit method, which searches for stars showing periodic dips in their brightness as a telltale sign of an orbiting object crossing in front of the star and blocking a portion of its light.
The signal was then confirmed as a planet using precision observations from the HPF spectrograph.
“This warm Jupiter is a compelling target for atmospheric characterization with upcoming missions like the James Webb Space Telescope,” said co-author Professor Suvrath Mahadevan, also from the Department of Astronomy and Astrophysics and the Center for Exoplanets and Habitable Worlds at the Pennsylvania State University.
The team’s paper was published in the Astronomical Journal.
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Caleb I. Cañas et al. 2020. A Warm Jupiter Transiting an M Dwarf: A TESS Single-transit Event Confirmed with the Habitable-zone Planet Finder. AJ 160, 147; doi: 10.3847/1538-3881/abac67
