Astronomers using NASA’s Transiting Exoplanet Survey Satellite (TESS) have discovered a massive exoplanet orbiting two stars in the TOI-1338 system.
An artist’s impression of TOI-1338b and its two host stars. Image credit: NASA’s Goddard Space Flight Center / Chris Smith.
TOI-1338 is a binary stellar system located 1,317 light-years away in the constellation of Pictor.
Also known as TIC 260128333, TYC 8533-950-1 and 2MASS J06083197-5932280, the system consists of two eclipsing stars that orbit each other with a period of 14.6 days.
One star, TOI-1338A, is about 10% more massive than our Sun, while the other, TOI-1338B, is cooler, dimmer and only one-third the Sun’s mass.
Dubbed TOI-1338b, the newfound exoplanet is 6.9 times the size of Earth.
The planet’s period is roughly 95 days with negligible eccentricity and its orbit is aligned to within 2 degrees of the binary system’s orbital plane.
TESS only sees the transits crossing TOI-1338A; the transits of the smaller star are too faint to detect.
“These are the types of signals that algorithms really struggle with,” said Dr. Veselin Kostov, an astronomer at NASA’s Goddard Space Flight Center and the SETI Institute.
“The human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems.”
After identifying TOI-1338b, Dr. Kostov and colleagues used a software package called ‘Eleanor’ — named after Eleanor Arroway, the central character in Carl Sagan’s novel ‘Contact’ — to confirm the transits were real and not a result of instrumental artifacts.
Using archival data from ground-based telescopes, they analyzed the TOI-1338 system and confirmed the planet.
“Our analysis confirmed the transit was caused by a circumbinary planet and we were able to measure the planet’s properties,” said Dr. Jerome Orosz, an astronomer at San Diego State University.
“The TOI-1338 system demonstrates the discovery potential of TESS for circumbinary planets, and provides further understanding of the formation and evolution of planets orbiting close binary stars,” the researchers said.
They presented the findings January 7 at the 235th Meeting of the American Astronomical Society in Honolulu, Hawai’i.
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V. Kostov et al. 2020. The First Circumbinary Planet Discovered by TESS. 235th AAS Meeting, abstract # 349.05
