Problem Planets: Understanding the Formation of Giant Planets around Low Mass Stars

摘要: Planetary formation models predict that giant planets should not form around stars with masses less than 0.5 M_Sun. This is due to two fundamental factors:(1) slow accretion due to long orbital timescales, and (2) low protoplanetary disk masses, limiting the available planetary building material. Nature has proven this prediction wrong. The TESS mission has recently enabled the discovery of the first transiting giants around low mass stars. We propose to obtain NIRSpec/PRISM transmission spectra for the only two well-characterized giant exoplanets that transit M dwarfs with masses less than 0.5 M_Sun: TOI-3235b and TOI-5205b. We will characterize their atmospheric enrichment and composition with precisions in [Fe/H] and C/O ratios better than~ 0.22 dex and~ 0.13, respectively, observing one transit per target. We will use these measurements to constrain the formation pathways for these planets. A modest …