We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey ...Satellite (TESS) as TESS objects of interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 MJup , and radii between 0.81 and 1.66 RJup . These targets have masses near the uncertain lower limit of hydrogen core fusion (~73-96 MJup ), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 ± 0.1 Gyr) and TOI-681 (0.17 ± 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 ± 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.
As an all-sky survey, NASA’s Transiting Exoplanet Survey Satellite (TESS) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable ...study of the evolutionary processes that occur within the first billion years. Here we report the discovery of a young, multiplanet system orbiting the bright K4.5V star, TOI-712 (V = 10.838, M* = 0.733+0.026-0.025 M⨀, R* = 0.674 ± 0.016 R⨀, Teff = 4622+61-60 K). From the TESS light curve, we measure a rotation period of 12.48 days and derive an age between about 500 Myr and 1.1 Gyr. The photometric observations reveal three transiting mini-Neptunes (Rb = 2.049+0.120-0.080 R⊕, Rc = 2.701+0.092-0.082 R⊕, Rd = 2.474+0.090-0.082 R⊕), with orbital periods of Pb = 9.531 days, Pc = 51.699 days, and Pd = 84.839 days. After modeling the three-planet system, an additional Earth-sized candidate is identified, TOI-712.05 (P = 4.32 days, RP = 0.81 ± 0.11 R⊕). We calculate that the habitable zone falls between 0.339 and 0.844 au (82.7 and 325.3 days), placing TOI-712 d near its inner edge. Among planetary systems harboring temperate planets, TOI-712 (T = 9.9) stands out as a relatively young star bright enough to motivate further characterization.
As an all-sky survey, NASA's \(TESS\) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable study of the evolutionary processes ...that occur within the first billion years. Here, we report the discovery of a young, multi-planet system orbiting the bright K4.5V star, TOI-712 (\(V = 10.838\), \(M_\star = 0.733_{-0.025}^{+0.026} M_\odot\), \(R_\star = 0.674\pm0.016 R_\odot\), \(T_{\rm eff} = 4622_{-60}^{+61}\) K). From the \(TESS\) light curve, we measure a rotation period of 12.48 days, and derive an age between about \(500\) Myr and 1.1 Gyr. The photometric observations reveal three transiting mini-Neptunes (\(R_b = 2.049^{+0.12}_{-0.080} R_\oplus\), \(R_c = 2.701^{+0.092}_{-0.082} R_\oplus\), \(R_d = 2.474^{+0.090}_{-0.082} R_\oplus \)), with orbital periods of \(P_b = 9.531\) days, \(P_c = 51.699\) days, and \(P_d = 84.839\) days. After modeling the three-planet system, an additional Earth-sized candidate is identified, TOI-712.05 (\(P = 4.32\) days, \(R_P = 0.81 \pm 0.11 R_\oplus\)). We calculate that the habitable zone falls between 0.339 and 0.844 au (82.7 and 325.3 days), placing TOI-712 d near its inner edge. Among planetary systems harboring temperate planets, TOI-712 (\(T = 9.9\)) stands out as a relatively young star bright enough to motivate further characterization.
We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey ...Satellite (TESS) as TESS Objects of Interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 \(\mathrm{M_{Jup}}\), and radii between 0.81 and 1.66 \(\mathrm{R_{Jup}}\). These targets have masses near the uncertain lower limit of hydrogen core fusion (\(\sim\)73-96 \(\mathrm{M_{Jup}}\)), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 \(\pm\) 0.1 Gyr) and TOI-681 (0.17 \(\pm\) 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 \(\pm\) 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.
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