High-resolution Spectra and Biosignatures of Earth-like Planets Transiting White Dwarfs


Temperature and mixing ratio profiles of Earth-like planet models orbiting WDs (top) at the Earth-equivalent distance and (bottom) on a specific orbit which allows for the maximum time in the WD HZ as the WD cools, shown for 3 evolutionary stages.

With the first observations of debris disks as well as proposed planets around white dwarfs, the question of how rocky planets around such stellar remnants can be characterized and probed for signs of life becomes tangible.


White dwarfs are similar in size to Earth and have relatively stable environments for billions of years after initial cooling, making them intriguing targets for exoplanet searches and terrestrial planet atmospheric characterization. Their small size and the resulting large planet transit signal allows observations with next generation telescopes to probe the atmosphere of such rocky planets, if they exist. We model high-resolution transmission spectra for planets orbiting white dwarfs from as they cool from 6,000-4,000 K, for i) planets receiving equivalent irradiation to modern Earth, and ii) planets orbiting at the distance around a cooling white dwarf which allows for the longest continuous time in the habitable zone.

All high-resolution transmission spectra will be publicly available online upon publication of this study and can be used as a tool to prepare and interpret upcoming observations with JWST, the Extremely Large Telescopes as well as mission concepts like Origins, HabEx, and LUVOIR.

Thea Kozakis, Zifan Lin, Lisa Kaltenegger
(Submitted on 31 Dec 2019)
Comments: 10 pages, 1 table, 4 figures; submitted to ApJL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2001.00049 [astro-ph.EP] (or arXiv:2001.00049v1 [astro-ph.EP] for this version)
Submission history
From: Thea Kozakis
[v1] Tue, 31 Dec 2019 19:42:04 UTC (391 KB)
https://arxiv.org/abs/2001.00049
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