HAT-P-26b: A Neptune-Mass Exoplanet with a Well Constrained Heavy Element Abundance

Hannah R. Wakeford, David K. Sing, Tiffany Kataria, Drake Deming, Nikolay Nikolov, Eric D. Lopez, Pascal Tremblin, David S. Amundsen, Nikole K. Lewis, Avi M. Mandell, Jonathan J. Fortney, Heather Knutson, Björn Benneke, Thomas M. Evans
(Submitted on 11 May 2017)

A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System, and has served as a cornerstone of planet formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 microns, we conducted a detailed atmospheric study of the transiting Neptune-mass exoplanet HAT-P-26b. We detected prominent H2O absorption bands with a maximum base-to-peak amplitude of 525ppm in the transmission spectrum. Using the water abundance as a proxy for metallicity, we measured HAT-P-26b’s atmospheric heavy element content [4.8 (-4.0 +21.5) times solar]. This likely indicates that HAT-P-26b’s atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime, with little contamination from metal-rich planetesimals.

Comments:    Published in Science – Report: 13 pages (preprint), 3 figures, 1 table – Supplementary material: 14 pages, 5 figures, 2 tables
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
DOI:    10.1126/science.aah4668
Cite as:    arXiv:1705.04354 [astro-ph.EP] (or arXiv:1705.04354v1 [astro-ph.EP] for this version)
Submission history
From: Hannah R Wakeford
[v1] Thu, 11 May 2017 19:07:49 GMT (3613kb)
https://arxiv.org/abs/1705.04354