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Sulphur dioxide in the mid-infrared transmission spectrum of WASP-39b
Diana Powell, Adina D. Feinstein, Elspeth K. H. Lee +70
The recent inference of sulphur dioxide (SO) in the atmosphere of the hot (1100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that phot…
Identifying and Fitting Eclipse Maps of Exoplanets with Cross-Validation
Mark Hammond, Neil T. Lewis, Sasha Boone +10
Eclipse mapping uses the shape of the eclipse of an exoplanet to measure its two-dimensional structure. Light curves are mostly composed of longitudinal information, with the latit…
Outflowing helium from a mature mini-Neptune
Michael Zhang, Fei Dai, Jacob L. Bean +2
We announce the detection of escaping helium from TOI 2134b, a mini-Neptune a few Gyr old. The average in-transit absorption spectrum shows a peak of 0.37 +- 0.05% and an equivalen…
Transmission spectroscopy of the lowest-density gas giant: metals and a potential extended outflow in HAT-P-67b
Aaron Bello-Arufe, Heather A. Knutson, João M. Mendonça +6
Extremely low-density exoplanets are tantalizing targets for atmospheric characterization because of their promisingly large signals in transmission spectroscopy. We present the fi…
A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve
Eliza M. -R. Kempton, Michael Zhang, Jacob L. Bean +30
There are no planets intermediate in size between Earth and Neptune in our Solar System, yet these objects are found around a substantial fraction of other stars. Population statis…
The Hazy and Metal-Rich Atmosphere of GJ 1214 b Constrained by Near and Mid-Infrared Transmission Spectroscopy
Peter Gao, Anjali A. A. Piette, Maria E. Steinrueck +12
The near-infrared transmission spectrum of the warm sub-Neptune exoplanet GJ 1214 b has been observed to be flat and featureless, implying a high metallicity atmosphere with abunda…
Confirmation of sub-solar metallicity for WASP-77Ab from JWST thermal emission spectroscopy
Prune C. August, Jacob L. Bean, Michael Zhang +4
We present the dayside thermal emission spectrum of WASP-77Ab from 2.8 -- 5.2 m as observed with the NIRSpec instrument on the James Webb Space Telescope (JWST). WASP-77Ab was p…
High atmospheric metal enrichment for a Saturn-mass planet
Jacob L. Bean, Qiao Xue, Prune C. August +9
Atmospheric metal enrichment (i.e., elements heavier than helium, also called "metallicity") is a key diagnostic of the formation of giant planets. The giant planets of the solar s…
Non-detection of He I in the atmosphere of GJ1214b with Keck/NIRSPEC, at a time of minimal telluric contamination
Jessica J. Spake, Antonija Oklopčić, Lynne. A. Hillenbrand +7
Observations of helium in exoplanet atmospheres may reveal the presence of large gaseous envelopes, and indicate ongoing atmospheric escape. Orell-Miquel et al. (2022) used CARMENE…
Detection of Atmospheric Escape from Four Young Mini Neptunes
Michael Zhang, Heather A. Knutson, Fei Dai +5
We use Keck/NIRSPEC to survey a sample of of young (1 Gyr), short period mini Neptunes orbiting nearby K dwargs to measure their mass loss via the metastable helium line. We det…
More Evidence for Variable Helium Absorption from HD 189733b
Michael Zhang, P. Wilson Cauley, Heather A. Knutson +5
We present a new Keck/NIRSPEC observation of metastable helium absorption from the upper atmosphere of HD 189733b, a hot Jupiter orbiting a nearby moderately active star. We measur…
Escaping Helium from TOI 560.01, a Young Mini Neptune
Michael Zhang, Heather A. Knutson, Lile Wang +2
We report helium absorption from the escaping atmosphere of TOI 560.01 (HD 73583b), a , d mini Neptune orbiting a young (600 Myr) K dwarf. Using Keck/…
Detection of Ongoing Mass Loss from HD 63433c, a Young Mini Neptune
Michael Zhang, Heather A. Knutson, Lile Wang +9
We detect Lyman absorption from the escaping atmosphere of HD 63433c, a , d mini Neptune orbiting a young (440 Myr) solar analogue in the Ursa Major M…
No escaping helium from 55 Cnc e
Michael Zhang, Heather A. Knutson, Lile Wang +3
We search for escaping helium from the hot super Earth 55 Cnc e by taking high-resolution spectra of the 1083 nm line during two transits using Keck/NIRSPEC. We detect no helium ab…
PLATON II: New Capabilities And A Comprehensive Retrieval on HD 189733b Transit and Eclipse Data
Michael Zhang, Yayaati Chachan, Eliza M. -R. Kempton +3
Recently, we introduced PLanetary Atmospheric Tool for Observer Noobs (PLATON), a Python package that calculates model transmission spectra for exoplanets and retrieves atmospheric…
The Orbit of WASP-12b is Decaying
Samuel W. Yee, Joshua N. Winn, Heather A. Knutson +6
WASP-12b is a transiting hot Jupiter on a 1.09-day orbit around a late-F star. Since the planet's discovery in 2008, the time interval between transits has been decreasing by $29\p…
A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
Yayaati Chachan, Heather A. Knutson, Peter Gao +14
We present the first comprehensive look at the m transmission spectrum of the warm ( K) Neptune HAT-P-11b derived from thirteen individual transits observed u…
Mass Loss from the Exoplanet WASP-12b Inferred from Phase Curves
Taylor J. Bell, Michael Zhang, Patricio E. Cubillos +12
The exoplanet WASP-12b is the prototype for the emerging class of ultra-hot, Jupiter-mass exoplanets. Past models have predicted---and near ultra-violet observations have shown---t…
Forward modelling and retrievals with PLATON, a fast open source tool
Michael Zhang, Yayaati Chachan, Eliza M. -R. Kempton +1
We introduce PLanetary Atmospheric Transmission for Observer Noobs (PLATON), a Python package that calculates transmission spectra for exoplanets and retrieves atmospheric characte…
Detection of a Westward Hotspot Offset in the Atmosphere of a Hot Gas Giant CoRoT-2b
Lisa Dang, Nicolas B. Cowan, Joel C. Schwartz +9
Short-period planets exhibit day-night temperature contrasts of hundreds to thousands of degrees K. They also exhibit eastward hotspot offsets whereby the hottest region on the pla…
Phase curves of WASP-33b and HD 149026b and a New Correlation Between Phase Curve Offset and Irradiation Temperature
Michael Zhang, Heather A. Knutson, Tiffany Kataria +9
We present new 3.6 and 4.5 Spitzer phase curves for the highly irradiated hot Jupiter WASP-33b and the unusually dense Saturn-mass planet HD 149026b. As part of this analysis,…
Stars Get Dizzy After Lunch
Michael Zhang, Kaloyan Penev
Exoplanet searches have discovered a large number of 'hot Jupiters'--high-mass planets orbiting very close to their parent stars in nearly circular orbits. A number of these planet…
POET: A Model for (P)lanetary (O)rbital (E)volution due to (T)ides on Evolving Stars
Kaloyan Penev, Michael Zhang, Brian Jackson
We make publicly available an efficient, versatile, easy to use and extend tool for calculating the evolution of circular aligned planetary orbits due to the tidal dissipation in t…