Radial velocity measurements of HR 8799 b and c with medium resolution spectroscopy
Abstract
High-contrast medium resolution spectroscopy has been used to detect molecules such as water and carbon monoxide in the atmospheres of gas giant exoplanets. In this work, we show how it can be used to derive radial velocity (RV) measurements of directly imaged exoplanets. Improving upon the traditional cross-correlation technique, we develop a new likelihood based on joint forward modeling of the planetary signal and the starlight background (i.e., speckles). After marginalizing over the starlight model, we infer the barycentric RV of HR 8799 b and c in 2010 yielding -9.2 ± 0.5 km s-1 and -11.6 ± 0.5 km s-1, respectively. These RV measurements help to constrain the 3D orientation of the orbit of the planet by resolving the degeneracy in the longitude of an ascending node. Assuming coplanar orbits for HR 8799 b and c, but not including d and e, we estimate Ω = 89 º -17 +27 and i = 20 º. 8 -3.7 +4.5.
Citation
Ruffio , J-B , Macintosh , B , Konopacky , Q M , Barman , T , De Rosa , R J , Wang , J J , Wilcomb , K K , Czekala , I & Marois , C 2019 , ' Radial velocity measurements of HR 8799 b and c with medium resolution spectroscopy ' , Astronomical Journal , vol. 158 , no. 5 , 200 . https://doi.org/10.3847/1538-3881/ab4594
Publication
Astronomical Journal
Status
Peer reviewed
ISSN
0004-6256Type
Journal article
Description
Funding: The research was supported by grants from NSF, including AST-1411868 (J.-B.R., B.M.), 1614492, and 1614492 (T.S.B.). Support was provided by grants from the National Aeronautics and Space Administration (NASA) NNX15AD95G (J.-B.R., R.J.D.R.).Collections
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