Exoplanet atmospheres: publications

Into the red: an M-band study of the chemistry and rotation of β Pictoris b at high spectral resolution

Monthly Notices of the Royal Astronomical Society, Volume 531, Issue 2, pp.2356-2378

Authors:

Luke T. Parker, Jayne L. Birkby, Rico Landman, Joost P. Wardenier, Mitchell E. Young, Sophia R. Vaughan, Lennart van Sluijs, Matteo Brogi, Vivien Parmentier and Michael R. Line

Abstract:

High-resolution cross-correlation spectroscopy (HRCCS) combined with adaptive optics has been enormously successful in advancing our knowledge of exoplanet atmospheres, from chemistry to rotation and atmospheric dynamics. This powerful technique now drives major science cases for ELT instrumentation including METIS/ELT, GMTNIRS/GMT, and MICHI/TMT, targeting biosignatures on rocky planets at 3-5 μm, but remains untested beyond 3.5 μm where the sky thermal background begins to provide the dominant contribution to the noise. We present 3.51-5.21 μm M-band CRIRES+/VLT observations of the archetypal young directly imaged gas giant β Pictoris b, detecting CO absorption at S/N = 6.6 at 4.73 μm and H2O at S/N = 5.7, and thus extending the use of HRCCS into the thermal background noise dominated infrared. Using this novel spectral range to search for more diverse chemistry, we report marginal evidence of SiO at S/N = 4.3, potentially indicative that previously proposed magnesium-silicate clouds in the atmosphere are either patchy, transparent at M-band wavelengths, or possibly absent on the planetary hemisphere observed. The molecular detections are rotationally broadened by the spin of β Pic b, and we infer a planetary rotation velocity of vsin(i) = 22 ± 2 km s-1 from the cross-correlation with the H2O model template, consistent with previous K-band studies. We discuss the observational challenges posed by the thermal background and telluric contamination in the M-band, the custom analysis procedures required to mitigate these issues, and the opportunities to exploit this new infrared window for HRCCS using existing and next-generation instrumentation.

Dynamics and clouds in planetary atmospheres from telescopic observations

Astronomy and Astrophysics Review Springer 31:1 (2023) 5

Authors:

Agustin Sanchez-Lavega, Patrick Irwin, Antonio Garcia Munoz

Abstract:

This review presents an insight into our current knowledge of the atmospheres of the planets Venus, Mars, Jupiter, Saturn, Uranus and Neptune, the satellite Titan, and those of exoplanets. It deals with the thermal structure, aerosol properties (hazes and clouds, dust in the case of Mars), chemical composition, global winds, and selected dynamical phenomena in these objects. Our understanding of atmospheres is greatly benefitting from the discovery in the last 3 decades of thousands of exoplanets. The exoplanet properties span a broad range of conditions, and it is fair to expect as much variety for their atmospheres. This complexity is driving unprecedented investigations of the atmospheres, where those of the solar systems bodies are the obvious reference. We are witnessing a significant transfer of knowledge in both directions between the investigations dedicated to Solar System and exoplanet atmospheres, and there are reasons to think that this exchange will intensity in the future. We identify and select a list of research subjects that can be conducted at optical and infrared wavelengths with future and currently available ground-based and space-based telescopes, but excluding those from the space missions to solar system bodies.

Ground-breaking Exoplanet Science with the ANDES spectrograph at the ELT

(2023)

Authors:

Enric Palle, Katia Biazzo, Emeline Bolmont, Paul Molliere, Katja Poppenhaeger, Jayne Birkby, Matteo Brogi, Gael Chauvin, Andrea Chiavassa, Jens Hoeijmakers, Emmanuel Lellouch, Christophe Lovis, Roberto Maiolino, Lisa Nortmann, Hannu Parviainen, Lorenzo Pino, Martin Turbet, Jesse Wender, Simon Albrecht, Simone Antoniucci, Susana C Barros, Andre Beaudoin, Bjorn Benneke, Isabelle Boisse, Aldo S Bonomo, Francesco Borsa, Alexis Brandeker, Wolfgang Brandner, Lars A Buchhave, Anne-Laure Cheffot, Robin Deborde, Florian Debras, Rene Doyon, Paolo Di Marcantonio, Paolo Giacobbe, Jonay I Gonzalez Hernandez, Ravit Helled, Laura Kreidberg, Pedro Machado, Jesus Maldonado, Alessandro Marconi, BL Canto Martins, Adriano Miceli, Christoph Mordasini, Mamadou N'Diaye, Andrezj Niedzielski, Brunella Nisini, Livia Origlia, Celine Peroux, Alex GM Pietrow, Enrico Pinna, Emily Rauscher, Sabine Reffert, Philippe Rousselot, Nicoletta Sanna, Adrien Simonnin, Alejandro Suarez Mascareno, Alessio Zanutta, Mathias Zechmeister

Methane throughout the atmosphere of the warm exoplanet WASP-80b

Nature Springer Nature 623:7988 (2023) 709-712

Authors:

Taylor J Bell, Luis Welbanks, Everett Schlawin, Michael R Line, Jonathan J Fortney, Thomas P Greene, Kazumasa Ohno, Vivien Parmentier, Emily Rauscher, Thomas G Beatty, Sagnick Mukherjee, Lindsey S Wiser, Martha L Boyer, Marcia J Rieke, John A Stansberry

Latitudinal variations in methane abundance, aerosol opacity and aerosol scattering efficiency in Neptune's atmosphere determined from VLT/MUSE

Journal of Geophysical Research: Planets American Geophysical Union 128:11 (2023) e2023JE007980

Authors:

Patrick Irwin, Jack Dobinson, Arjuna James, Wong Michael, Fletcher Leigh, Roman Michael, Teanby Nicholas, Orton Glenn, Perez-Hoyos Santiago, Sanchez-Lavega Agustin, Simon Amy, Morales-Juberias Raul, de Pater Imke

Abstract:

Spectral observations of Neptune made in 2019 with the MUSE instrument at the Very Large Telescope in Chile have been analysed to determine the spatial variation of aerosol scattering properties and methane abundance in Neptune’s atmosphere. The darkening of the South Polar Wave (SPW) at ∼ 60◦S, and dark spots such as the Voyager 2 Great Dark Spot is concluded to be due to a spectrally-dependent darkening (λ < 650nm) of particles in a deep aerosol layer at ∼ 5 bar and presumed to be composed of a mixture of ~ 650 nm, with bright zones latitudinally separated by ∼ 25◦ . This feature, similar to the spectral characteristics of a discrete deep bright spot DBS-2019 found in our data, is found to be consistent with a brightening of the particles in the same ∼5-bar aerosol layer at λ > 650 nm. We find the properties of an overlying methane/haze aerosol layer at ∼ 2 bar are, to first-order, invariant with latitude, while variations in the opacity of an upper tropospheric haze layer reproduce the observed reflectivity at methane-absorbing wavelengths, with higher abundances found at the equator and also in a narrow ‘zone’ at 80◦S. Finally, we find the mean abundance of methane below its condensation level to be 6-7% at the equator reducing to ∼3% south of ∼25◦S, although the absolute abundances are model dependent.

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