Abstract
We present moderate-resolution (R ∼ 4000) K-band spectra of the "super-Jupiter,"κ Andromedae b. The data were taken with the OSIRIS integral field spectrograph at Keck Observatory. The spectra reveal resolved molecular lines from H2O and CO, and are compared to a custom PHOENIX atmosphere model grid appropriate for young planetary-mass objects. We fit the data using a Markov chain Monte Carlo forward-modeling method. Using a combination of our moderate-resolution spectrum and low-resolution, broadband data from the literature, we derive an effective temperature of T eff = 1950-2150 K, a surface gravity of, and a metallicity of [M/H] =-0.2-0.0. These values are consistent with previous estimates from atmospheric modeling and the currently favored young age of the system (<50 Myr). We derive a C/O ratio of for the source, broadly consistent with the solar C/O ratio. This, coupled with the slightly subsolar metallicity, implies a composition consistent with that of the host star, and is suggestive of formation by a rapid process. The subsolar metallicity of κ Andromedae b is also consistent with predictions of formation via gravitational instability. Further constraints on formation of the companion will require measurement of the C/O ratio of κ Andromedae A. We also measure the radial velocity of κ Andromedae b for the first time, with a value of-1.4 ± 0.9 km s-1 relative to the host star. We find that the derived radial velocity is consistent with the estimated high eccentricity of κ Andromedae b.
Original language | English (US) |
---|---|
Article number | 207 |
Journal | Astronomical Journal |
Volume | 160 |
Issue number | 5 |
DOIs | |
State | Published - Nov 2020 |
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Fingerprint
Dive into the research topics of 'Moderate-resolution K-band Spectroscopy of Substellar Companion κ Andromedae b'. Together they form a unique fingerprint.Datasets
-
OSIRIS K-band spectroscopy of {kappa} Andromedae b
Wilcomb, K. K. (Creator), Konopacky, Q. M. (Creator), Barman, T. S. (Creator), Theissen, C. A. (Creator), Ruffio, J.-B. (Creator), Brock, L. (Creator), MacIntosh, B. (Contributor) & Marois, C. (Creator), Centre de Donnees Strasbourg (CDS), 2021
DOI: 10.26093/cds/vizier.51600207, https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/160/207
Dataset