15NH3 in the atmosphere of a cool brown dwarf
Abstract
Brown dwarfs serve as ideal laboratories for studying the atmospheres of giant exoplanets on wide orbits as the governing physical and chemical processes in them are nearly identical. Understanding the formation of gas giant planets is challenging, often involving the endeavour to link atmospheric abundance ratios, such as the carbon-to-oxygen (C/O) ratio, to formation scenarios. However, the complexity of planet formation requires additional tracers, as the unambiguous interpretation of the measured C/O ratio is fraught with complexity. Isotope ratios, such as deuterium-to-hydrogen and 14N/15N, offer a promising avenue to gain further insight into this formation process, mirroring their utility within the solar system. For exoplanets only a handful of constraints on 12C/13C exist, pointing to the accretion of 13C-rich ice from beyond the disks' CO iceline. Here we report on the mid-infrared detection of the 14NH3 and 15NH3 isotopologues in the atmosphere of a cool brown dwarf with an effective temperature of 380 K in a spectrum taken with the Mid-InfraRed Instrument of the James Webb Space Telescope. As expected, our results reveal a 14N/15N value consistent with star-like formation by gravitational collapse, demonstrating that this ratio can be accurately constrained. Since young stars and their planets should be more strongly enriched in the 15N isotope, we expect that 15NH3 will be detectable in a number of cold, wide-separation exoplanets.
Keywords
Cite
@article{arxiv.2311.08054,
title = {15NH3 in the atmosphere of a cool brown dwarf},
author = {David Barrado and Paul Mollière and Polychronis Patapis and Michiel Min and Pascal Tremblin and Francisco Ardevol Martinez and Niall Whiteford and Malavika Vasist and Ioannis Argyriou and Matthias Samland and Pierre-Olivier Lagage and Leen Decin and Rens Waters and Thomas Henning and María Morales-Calderón and Manuel Guedel and Bart Vandenbussche and Olivier Absil and Pierre Baudoz and Anthony Boccaletti and Jeroen Bouwman and Christophe Cossou and Alain Coulais and Nicolas Crouzet and René Gastaud and Alistair Glasse and Adrian M. Glauser and Inga Kamp and Sarah Kendrew and Oliver Krause and Fred Lahuis and Michael Mueller and Göran Olofsson and John Pye and Daniel Rouan and Pierre Royer and Silvia Scheithauer and Ingo Waldmann and Luis Colina and Ewine F. van Dishoeck and Tom Ray and Göran Östlin and Gillian Wright},
journal= {arXiv preprint arXiv:2311.08054},
year = {2023}
}
Comments
Accepted by Nature. 28 pages, 7 figures, uses nature3.cls