An international team of astronomers has discovered two new extrasolar planets using NASA’s Transiting Exoplanet Survey Satellite (TESS). The newly discovered alien worlds, TOI-5152 b, and TOI-5153 b are the size of Jupiter but are approximately three times more massive than the solar system’s largest planet. The discovery was published on the arXiv pre-print repository on July 8.
TESS is surveying approximately 200,000 of the brightest stars near the sun in search of transiting exoplanets. Over 5,700 candidate exoplanets (TESS Objects of Interest, or TOI) have been identified, with 227 confirmed so far.
Another two TOI planets monitored by TESS have recently been confirmed by a group of astronomers led by Solène Ulmer-Moll of the Geneva Observatory in Switzerland. They claim to have discovered transit signals in the light curves of two stars known as TOI-5152 and TOI-5153. Follow-up observations confirmed the planetary nature of these signals.
“The discovery photometry was collected with the space-based mission TESS, and follow-up observations were conducted from the ground with the photometric facility NGTS, as well as the high-resolution spectrographs CORALIE, FEROS, CHIRON, HARPS, and TRES,” the researchers wrote in the paper.
TOI-5152 b has a radius of about 1.07 Jupiter radii and is three times the mass of Jupiter. It orbits its parent star every 54.19 days and is 0.31 AU away from it. The equilibrium temperature of the planet was determined to be 688 K. TOI-5152 is a G1-type star nearly two times the size of the sun located about 1,200 light years from Earth. It is thought to be between 1.4 and 6.8 billion years old.
TOI-5153 b has a mass of 3.26 Jupiter masses and a radius of 1.06 Jupiter radii, according to estimates. This exoplanet’s orbital period is 20.33 days, and its distance from the host is nearly 0.16 AU. The astronomers determined that the equilibrium temperature of TOI-5153 b is 906 K. The parent star’s spectral type is F8. It is approximately 40% larger than the sun and is thought to be 5.4 billion years old. This planetary system is approximately 1,270 light years away.
TOI-5152 b and TOI-5153 b are thus warm and massive alien worlds the size of Jupiter. They are both metal-enriched, and their heavy element content is consistent with the mass-metallicity relation of gas giants, according to the astronomers. The authors of the paper added that because the two planets orbit moderately bright stars, they are ideal targets for additional observations.
“Both warm Jupiters orbit moderately bright host stars, making them valuable targets for follow-up studies of the planetary atmosphere and measurement of the system’s spin-orbit angle,” the researchers concluded.