A carbon-rich atmosphere on a windy pulsar planet
2025/09/04 by Michael Zhang, Maya Beleznay, Zhang, Michael +43 · 7 voices · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.2509.04558
openalex publication_date 2025/09/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract
A handful of enigmatic Jupiter-mass objects have been discovered orbiting pulsars. One such object, PSR J2322-2650b, uniquely resembles a hot Jupiter exoplanet due to its minimum density of 1.8 g/cm3 and its ~1900 K equilibrium temperature. We use JWST to observe PSR J2322-2650b's emission spectrum across an entire orbit. In stark contrast to every known exoplanet orbiting a main-sequence star, we find an atmosphere rich in molecular carbon (C3, C2) with strong westward winds. Our observations open up new exoplanetary chemical (ultra-high C/O and C/N ratios of >100 and >10,000, respectively) and dynamical regimes (ultra-fast rotation with external irradiation) to observational study. The extreme carbon enrichment poses a severe challenge to the current understanding of ``black widow'' companions, which were expected to consist of a wider range of elements due to their origins as stripped stellar cores.
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- Nature makes weird planets, and now this is among the weirdest: As big as Jupiter, made of carbon, blasted by high winds, and heated to 1900 degrees C by a dying, fast-spinning pulsar. No matter how b [bsky, 80 points, 5 comments]
- 👀👀👀👀 Super neat preprint! 📡🔭 A rare, hot-Jupiter exoplanet orbits the pulsar PSR J2322-2650. Astronomers used #JWST to observe it across the full orbit, and found its atmosphere rich in carbon A [bsky, 46 points, 4 comments]
- Découverte d'un astre en orbite autour d'une étoile à neutrons en rotation rapide, dont l'atmosphère est composée presque entièrement de... carbone pur. Il s'agit probablement des vestiges d'une ancie [bsky, 25 points, 1 comments]
- Any hard SF writers out there in search of a truly challenging new locale? arxiv.org/abs/2509.04558 [bsky, 18 points, 3 comments]
- A carbon-rich atmosphere on a windy pulsar planet: arxiv.org/abs/2509.04558 -> NASA’s Webb Observes Exoplanet Whose Composition Defies Explanation: science.nasa.gov/missions/web... [bsky, 1 points, 0 comments]
- Paper (published in The Astrophysical Journal Letters): arxiv.org/abs/2509.04558 NASA writeup: science.nasa.gov/missions/web... [bsky, 0 points, 0 comments]
- Some chemical atmospheric constituants of an exoplanet orbiting a pulsar have been identified. And they say this planet is lemon-shaped and bathed in gamma radiation. A "black-widow" binary star syste [bsky, 0 points, 0 comments]
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