An M dwarf accompanied by a close-in giant orbiter with SPECULOOS
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Date
2023-10
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Journal Article
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Abstract
In the last decade, a dozen close-in giant planets have been discovered orbiting stars with spectral types ranging from M0 to M4, a mystery since known formation pathways do not predict the existence of such systems. Here, we confirm TOI-4860 b, a Jupiter-sized planet orbiting an M4.5 host, a star at the transition between fully and partially convective interiors. First identified with TESS data, we validate the transiting companion’s planetary nature through multicolour photometry from the TRAPPIST-South/North, SPECULOOS, and MuSCAT3 facilities. Our analysis yields a radius of 0.76 ± 0.02 RJup for the planet, a mass of 0.34 M for the star, and an orbital period of 1.52 d. Using the newly commissioned SPIRIT InGaAs camera at the SPECULOOS-South Observatory, we collect infrared photometry in zYJ that spans the time of secondary eclipse. These observations do not detect a secondary eclipse, placing an upper limit on the brightness of the companion. The planetary nature of the companion is further confirmed through high-resolution spectroscopy obtained with the IRD spectrograph at Subaru Telescope, from which we measure a mass of 0.67 ± 0.14 MJup. Based on its overall density, TOI-4860 b appears to be rich in heavy elements, like its host star.
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published
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525 (1)
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Oxford University Press
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Subject
techniques: photometric; techniques: radial velocities; exoplanets; infrared: planetary systems
Organisational unit
09754 - Queloz, Didier / Queloz, Didier