Astronomers using NASA’s Transiting Exoplanet Survey Satellite (TESS) have discovered a trio of hot planets orbiting a much younger version of our Sun in the triple stellar system TOI-451.
This illustration sketches out the main features of the TOI-451 system. Image credit: NASA’s Goddard Space Flight Center.
Also known as CD-38 1467, TIC 257605131 and Gaia DR2 4844691297067063424, the system is only 120 million years old.
It consists of the young solar-mass star TOI-451 and its wide-binary companion, TOI-451B (itself a system of two red dwarfs).
“The parent star in this planetary system is very similar to our own Sun, but much younger,” said Dr. Elisabeth Newton, an astronomer in the Department of Physics and Astronomy at Dartmouth College.
“By studying these planets in the context of others, we can piece together the picture of how planets form and develop.”
Dr. Newton and her colleagues identified three planets transiting the central star TOI-451 in the TESS data and followed up the signals with observations from NASA’s Spitzer Space Telescope and ground-based telescopes: the Perth Exoplanet Survey Telescope and Las Cumbres Observatory.
“TOI-451b orbits every 1.9 days, is about 1.9 times Earth’s size, and its estimated mass ranges from two to 12 times Earth’s,” they said.
“The next planet out, TOI-451c, completes an orbit every 9.2 days, is about three times larger than Earth, and holds between three and 16 times Earth’s mass.”
“The farthest and largest world, TOI-451d, circles the star every 16 days, is four times the size of our planet, and weighs between four and 19 Earth masses.”
The TOI-451 system resides in the recently discovered Pisces-Eridanus stream, a collection of stars less than 3% the age of our Solar System that stretches across one-third of the sky.
“The Pisces-Eridanus stream offers a new set of young, nearby stars around which to search for planets,” the astronomers said.
“The stream complements the similarly-aged Pleiades, in which no exoplanets have been found to date.”
The discovery is described in a paper in the Astronomical Journal.
Elisabeth R. Newton et al. 2021. TESS Hunt for Young and Maturing Exoplanets (THYME). IV. Three Small Planets Orbiting a 120 Myr Old Star in the Pisces-Eridanus Stream. AJ 161, 65; doi: 10.3847/1538-3881/abccc6