A Measurement of the Water Abundance in the Atmosphere of the Hot Jupiter WASP-43b with High-resolution Cross-correlation Spectroscopy
Astronomical Journal 169:2 (2025)
Abstract:
Measuring the abundances of carbon- and oxygen-bearing molecules has been a primary focus in studying the atmospheres of hot Jupiters, as doing so can help constrain the carbon-to-oxygen (C/O) ratio. The C/O ratio can help reveal the evolution and formation pathways of hot Jupiters and provide a strong understanding of the atmospheric composition. In the last decade, high-resolution spectral analyses have become increasingly useful in measuring precise abundances of several carbon- and oxygen-bearing molecules. This allows for a more precise constraint of the C/O ratio. We present four transits of the hot Jupiter WASP-43b observed between 1.45 and 2.45 μm with the high-resolution Immersion GRating InfraRed Spectrometer on the Gemini-S telescope. We detected H2O at a signal-to-noise ratio of 3.51. We tested for the presence of CH4, CO, and CO2, but we did not detect these carbon-bearing species. We ran a retrieval for all four molecules and obtained a water abundance of log 10 ( H 2 O ) = − 2.2 4 − 0.48 + 0.57 . We obtained an upper limit on the C/O ratio of C/O < 0.95. These findings are consistent with previous observations from the Hubble Space Telescope and the James Webb Space Telescope.Phase-resolved Hubble Space Telescope WFC3 Spectroscopy of the Weakly Irradiated Brown Dwarf GD 1400 and Energy Redistribution-Irradiation Trends in Six White Dwarf-Brown Dwarf Binaries
Astrophysical Journal 979:2 (2025)
Abstract:
Irradiated brown dwarfs offer a unique opportunity to bridge the gap between stellar and planetary atmospheres. We present high-quality Hubble Space Telescope/Wide Field Camera 3/G141 phase-resolved spectra of the white dwarf-brown dwarf binary GD 1400, covering more than one full rotation of the brown dwarf. Accounting for brightness variations caused by ZZ Ceti pulsations, we revealed weak (∼1%) phase-curve amplitude modulations originating from the brown dwarf. Subband light-curve exploration in various bands showed no significant wavelength dependence on amplitude or phase shift. Extracted day- and nightside spectra indicated chemically similar hemispheres, with slightly higher dayside temperatures, suggesting efficient heat redistribution or the dominance of radiative escape over atmospheric circulation. A simple radiative and energy redistribution model reproduced the observed temperatures well. Cloud-inclusive models fit the day and night spectra better than cloudless models, indicating global cloud coverage. We also begin qualitatively exploring atmospheric trends across six irradiated brown dwarfs, from the now complete “Dancing with the Dwarfs” white dwarf-brown dwarf sample. The trend we find in the dayside/nightside temperature and irradiation levels is consistent with efficient heat redistribution for irradiation levels less than ∼109 erg s−1 cm−2 and decreasing efficiency above that level.Stellar surface information from the Ca II H&K lines -- II. Defining better activity proxies
(2024)
BOWIE-ALIGN: how formation and migration histories of giant planets impact atmospheric compositions
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 535:1 (2024) 171-186
A Gaussian process model for stellar activity in 2-D line profile time-series
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 535:1 (2024) stae2421