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Discovery Alert: TESS Serves up Two New Planets

Illustration of two gas giant exoplanets from NASA
Artist's rendering of possible gas giants.
NASA/Ames Research Center/Wendy Stenzel

Planets: TOI 216 b, TOI 216 c

Discovered by: Kipping et al.

Date: February 2019

Key facts: The newest discoveries from TESS – the Transiting Exoplanet Survey Satellite – add to a growing catalog of giant, gaseous planets orbiting other stars. A third gas giant, HD 221420, was also announced, a planet about 10 times the mass of Jupiter discovered with a ground-based telescope.

Details: TOI 216 b and c both orbit a star about 580 light years from Earth. TOI 216 b is a little more than half as big around as Jupiter. TOI 216 c is about as big around as Jupiter. The two planets also are in "orbital resonance" – that is, the outer planet, c, takes almost exactly twice as long to orbit the star as the inner planet. TOI 216 b takes 17 days to go once around its star – a year on this planet. TOI 216 c takes 34 days.

What's new: The latest discoveries bring to 13 the number of TESS planets confirmed so far. This planet hunter, launched in April 2018, looks for the tiny dip in starlight as a planet crosses the face of its star.