In:
The Astronomical Journal, American Astronomical Society, Vol. 162, No. 6 ( 2021-12-01), p. 295-
Abstract:
We present updated radial-velocity (RV) analyses of the AU Mic system. AU Mic is a young (22 Myr) early-M dwarf known to host two transiting planets— P b ∼ 8.46 days, R b = 4.38 − 0.18 + 0.18 R ⊕ , P c ∼ 18.86 days, R c = 3.51 − 0.16 + 0.16 R ⊕ . With visible RVs from Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical echelle Spectrographs (CARMENES)-VIS, CHIRON, HARPS, HIRES, M inerva -Australis, and Tillinghast Reflector Echelle Spectrograph, as well as near-infrared (NIR) RVs from CARMENES-NIR, CSHELL, IRD, iSHELL, NIRSPEC, and SPIRou, we provide a 5 σ upper limit to the mass of AU Mic c of M c ≤ 20.13 M ⊕ and present a refined mass of AU Mic b of M b = 20.12 − 1.57 + 1.72 M ⊕ . Used in our analyses is a new RV modeling toolkit to exploit the wavelength dependence of stellar activity present in our RVs via wavelength-dependent Gaussian processes. By obtaining near-simultaneous visible and near-infrared RVs, we also compute the temporal evolution of RV “color” and introduce a regressional method to aid in isolating Keplerian from stellar activity signals when modeling RVs in future works. Using a multiwavelength Gaussian process model, we demonstrate the ability to recover injected planets at 5 σ significance with semi-amplitudes down to ≈10 m s −1 with a known ephemeris, more than an order of magnitude below the stellar activity amplitude. However, we find that the accuracy of the recovered semi-amplitudes is ∼50% for such signals with our model.
Type of Medium:
Online Resource
ISSN:
0004-6256
,
1538-3881
DOI:
10.3847/1538-3881/ac2c80
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2021
detail.hit.zdb_id:
2207625-6
detail.hit.zdb_id:
2003104-X
SSG:
16,12
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