Astronomers using data from the HATNet (Hungarian-made Automated Telescope Network) survey have discovered a transiting giant planet orbiting the K5-type dwarf star HAT-P-68.

An artist’s impression of the hot-Jupiter exoplanet HAT-P-68b and its parent star HAT-P-68 (also known as GSC 1925-01046 and 2MASS 07535598+2356176), a K5-type dwarf star with a mass of 0.68 solar masses and a radius of 0.67 solar radii. Image credit: Sci-News.com.

An artist’s impression of the hot-Jupiter exoplanet HAT-P-68b and its parent star HAT-P-68 (also known as GSC 1925-01046 and 2MASS 07535598+2356176), a K5-type dwarf star with a mass of 0.68 solar masses and a radius of 0.67 solar radii. Image credit: Sci-News.com.

“The discoveries of planets with orbital periods shorter than 10 days provide advantages to resolving current theoretical challenges in the field,” said University of Washington astronomer Bethlee Lindor and colleagues.

“For instance, explaining the inflated radii of hot Jupiters remains a theoretical puzzle that may be elucidated by building up a larger sample objects to disentangle the effects of age, orbital separation, irradiation, composition and mass on the radii of these planets.”

“Explaining the origin of these planets as well as understanding how they evolve via planet-star interactions are subjects that can be better addressed with a larger sample of objects.”

The newfound short-period planet is a hot gas giant with a mass of 0.7 times that of Jupiter and a radius of 1.1 Jovian radii.

Named HAT-P-68b, it orbits its host star once every 2.3 days at a distance of just 0.03 AU.

The system is approximately 11.1 billion years old and is located 662 light-years away in the constellation of Gemini.

“The discovery of HAT-P-68b contributes to the relatively small sample of low-mass (late K dwarf, and M dwarf) stars with known transiting giant planets,” the astronomers said.

They detected the planet using data from the ground-based HATNet survey, which searches for planets transiting moderately bright stars by utilizing six small telephotolenses on robotic mounts.

“The discovery of HAT-P-68b by HATNet demonstrates that in the era of wide-field space-based transit surveys, interesting planets amenable to detailed characterization remain to be discovered, even from the ground,” they said.

The team’s paper will be published in the Astronomical Journal.

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Bethlee M. Lindor et al. 2020. HAT-P-68b: A Transiting Hot Jupiter around a K5 Dwarf Star. AJ, submitted for publication; arXiv: 2010.16026