Using NASA’s Transiting Exoplanet Survey Satellite (TESS) and several ground-based telescopes, astronomers have discovered and confirmed a warm super-Neptune orbiting the red dwarf TOI-1728.
An artist’s impression of the super-Neptune exoplanet TOI-1728b. Image credit: Sci-News.com.
TOI-1728 is an inactive M0-type star located 198 light-years away in the large northern constellation of Camelopardalis.
Also cataloged as TIC 285048486 and UCAC4 774-029023, the star is smaller and less massive than the Sun and is 7.1 billion years old.
The newly-discovered planet, named TOI-1728b, orbits its star every 3.5 days on a circular orbit.
The alien world is about 5 times the size of Earth and 26.8 times more massive, making it a super-Neptune, an intermediate subclass of planets between Neptune and the more massive gas-giant planets.
“TOI-1728b is the largest transiting super-Neptune around an M-dwarf host,” Pennsylvania State University astronomer Shubham Kanodia and colleagues wrote in their paper.
The astronomers detected TOI-1728b while poring over data collected by TESS.
They then observed several transits of the new planet using the Richard S. Perkin telescope on the campus of Hobart and William Smith Colleges and the 0.6-m telescope located on the roof of the Penn State Davey Laboratory.
They also observed the host star using the Habitable-Zone Planet Finder, a high-resolution spectrograph located at the 10-m Hobby-Eberly Telescope.
“With its relatively large mass and radius, TOI-1728 represents a valuable datapoint in the M-dwarf exoplanet mass-radius diagram, bridging the gap between the lighter Neptune-sized planets and the heavier Jovian planets known to orbit M-dwarfs,” the researchers wrote in the paper.
“With a low bulk density of 1.14 g/cm3, and orbiting a bright host star, TOI-1728b is also a promising candidate for transmission spectroscopy both from the ground and from space, which can be used to constrain planet formation and evolutionary models.”
The team’s paper will be published in the Astrophysical Journal.
_____
Shubham Kanodia et al. 2020. TOI-1728b: The Habitable-zone Planet Finder confirms a warm super Neptune orbiting an M dwarf host. ApJ, in press; arXiv: 2006.14546
