¹³CO and potential variability in β Pictoris b with GRAVITY+

2026/06/10 by Antonia von Stauffenberg, Jonas Sauter, Paul Mollière +18 · 1 voice
Physics and Astronomy · #astro-ph.EP

paper · pdf · doi:10.1051/0004-6361/202660275

Abstract

The ¹²CO/¹³CO ratio was introduced as an indicator for where in the disk a planet has formed. Previously a lower value compared to the host star's was suggested to show that a planet accreted CO ice beyond the disk's CO ice line. In this letter we aim to determine the ¹²CO/¹³CO value of the directly imaged planet β Pictoris b, and whether we can link it to its formation. Its apparent brightness results in an exceptional S/N of up to ~60 per wavelength point. We present the first science observations with the upgraded GRAVITY+ instrument at a spectral resolution of R ~ 4000, which we analyse with petitRADTRANS. Our retrievals robustly indicate the presence of ¹³CO with a ¹²CO/¹³CO ratio of 91⁺²⁴_-17, consistent with both a solar to ISM-like value. Our ¹²CO/¹³CO value corroborates recent interpretations that ¹³CO may be a less useful tracer of formation location in the disk than previously thought; nonetheless, we discuss theories with which this value is consistent. As our observations span ~7 hours, this enabled us to search for atmospheric variability in β Pictoris b; we report a tentative constraint on the variability amplitude of about 1.4^+0.6_-0.7%.

Discussions

• check out the papers here! von Stauffenberg et al. arxiv.org/pdf/2606.11972 Gapp et al. arxiv.org/pdf/2606.19487 [bsky, 2 points, 0 comments]

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