학술논문
Keck/KPIC Emission Spectroscopy of WASP-33b
Document Type
Working Paper
Author
Finnerty, Luke; Schofield, Tobias; Sappey, Ben; Xuan, Jerry W.; Ruffio, Jean-Baptiste; Wang, Jason J.; Delorme, Jacques-Robert; Blake, Geoffrey A.; Buzard, Cam; Fitzgerald, Michael P.; Baker, Ashley; Bartos, Randall; Bond, Charlotte Z.; Calvin, Benjamin; Cetre, Sylvain; Doppmann, Greg; Echeverri, Daniel; Jovanovic, Nemanja; Liberman, Joshua; Lopez, Ronald A.; Martin, Emily C.; Mawet, Dimitri; Morris, Evan; Pezzato, Jacklyn; Phillips, Caprice L.; Ragland, Sam; Skemer, Andrew; Venenciano, Taylor; Wallace, J. Kent; Wallack, Nicole L.; Wang, Ji; Wizinowich, Peter
Source
Subject
Language
Abstract
We present Keck/KPIC high-resolution ($R\sim35,000$) $K$-band thermal emission spectroscopy of the ultra-hot Jupiter WASP-33b. The use of KPIC's single-mode fibers greatly improves both blaze and line-spread stabilities relative to slit spectrographs, enhancing the cross-correlation detection strength. We retrieve the dayside emission spectrum with a nested sampling pipeline which fits for orbital parameters, the atmospheric pressure-temperature profile, and molecular abundances.We strongly detect the thermally-inverted dayside and measure mass-mixing ratios for CO ($\log\rm CO_{MMR} = -1.1^{+0.4}_{-0.6}$), H$_2$O ($\log\rm H_2O_{MMR} = -4.1^{+0.7}_{-0.9}$) and OH ($\log\rm OH_{MMR} = -2.1^{+0.5}_{-1.1}$), suggesting near-complete dayside photodissociation of H$_2$O. The retrieved abundances suggest a carbon- and possibly metal-enriched atmosphere, with a gas-phase C/O ratio of $0.8^{+0.1}_{-0.2}$, consistent with the accretion of high-metallicity gas near the CO$_2$ snow line and post-disk migration or with accretion between the soot and H$_2$O snow lines. We also find tentative evidence for $\rm ^{12}CO/^{13}CO \sim 50$, consistent with values expected in protoplanetary disks, as well as tentative evidence for a metal-enriched atmosphere (2--15$\times$ solar). These observations demonstrate KPIC's ability to characterize close-in planets and the utility of KPIC's improved instrumental stability for cross-correlation techniques.
Comment: Accepted in AJ, 26 pages, 12 figures
Comment: Accepted in AJ, 26 pages, 12 figures