Kavli Affiliate: Bruce Macintosh
| First 5 Authors: , , , ,
| Summary:
We present high-contrast direct spectroscopy of the low-mass, cool exoplanet
51 Eridani b (2-4 M$_textrmJup$, $sim$750 K) using JWST / NIRSpec in a
fixed-slit configuration (F290LP / G395H, $3-5,mu$m, R$sim$2,700). A cross
correlation analysis between the continuum-subtracted data and atmospheric
forward models indicates a detection of molecular signals of planetary origin
at $4.8sigma$ at the expected position and velocity of the planet. The
detection of the planetary signal is driven primarily by molecular features
from methane and carbon monoxide, providing the first direct confirmation of
these two molecules coexisting in chemical disequilibrium in the atmosphere of
51 Eridani b. A new comprehensive atmospheric model analysis shows consistency
between the ground-based IFU spectroscopy and the NIRSpec data, with the
best-fit model parameters: $T_mathrmeff$ = 800$^+21.5_-55.5$ K, $log g$
= 3.75$^+0.09_-0.37$, $[mathrmM/mathrmH]$ = 0.7$^+0.07_-0.21$,
$textrmC/textrmO$ = 0.458$^+0.08_-0.09$, $log K_mathrmzz$ =
3$^+0.47_-0.73$, $R_mathrmP$ = 1.36$^+0.07_-0.03$ $R_mathrmJup$,
$f_mathrmhole$ = 0.3$^+0.10_-0.07$, and the NIRSpec errorbar inflation
parameter: $hate$ = 1.74$^+0.02_-0.03$. We conclude with a discussion on
the lessons learned between the fixed slit and IFU-based high contrast
spectroscopic methods from our observing program, including some possibilities
to improve the analysis method.
| Search Query: ArXiv Query: search_query=au:”Bruce Macintosh”&id_list=&start=0&max_results=3