Two Bright M Dwarfs Hosting Ultra-Short-Period Super-Earths with Earth-like Compositions*
نویسندگان
چکیده
We present observations of two bright M dwarfs (TOI-1634 and TOI-1685: $J=9.5-9.6$) hosting ultra-short period (USP) planets, identified by the TESS mission. The stars are similar in temperature, mass, radius ($T_\mathrm{eff}\,\approx\,3500$ K, $M_\star\,\approx\,0.45-0.46\,M_\odot$, $R_\star\approx 0.45-0.46\,R_\odot$), planets both super-Earth-sized ($1.25\,R_\oplus<R_p<2.0\,R_\oplus$). For systems, light curves from ground-based photometry exhibit planetary transits, whose depths consistent with those photometry. also refine transit ephemerides based on photometry, finding orbital periods $P=0.9893436\pm0.0000020$ day $P=0.6691416\pm0.0000019$ for TOI-1634b TOI-1685b, respectively. Through intensive radial velocity (RV) using IRD Subaru 8.2m telescope, we confirm nature TOIs, measure their masses: $10.14\pm0.95\,M_\oplus$ $3.43\pm0.93\,M_\oplus$ respectively, when observed RVs fitted a single-planet circular-orbit model. Combining planet radii $R_p=1.749\pm 0.079\,R_\oplus$ (TOI-1634b) $1.459\pm0.065\,R_\oplus$ (TOI-1685b), find that USP have mean densities an Earth-like internal composition, which is typical small planets. currently most massive this category, it resides near valley, makes benchmark context discussing size limit rocky cores as well testing formation scenarios Excess scatter RV residuals TOI-1685 suggests presence possible secondary or unknown activity/instrumental noise data, but further required to check possibilities.
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 2021
ISSN: ['1538-3881', '0004-6256']
DOI: https://doi.org/10.3847/1538-3881/ac0fdc