NEID Reveals That the Young Warm Neptune TOI-2076 b Has a Low Obliquity

Robert C. Frazier, Gudmundur Stefánsson, Suvrath Mahadevan, Samuel W. Yee, Caleb I. Cañas, Joshua N. Winn, Jacob Luhn, Fei Dai, Lauren Doyle, Heather Cegla, Shubham Kanodia, Paul Robertson, John Wisniewski, Chad F. Bender, Jiayin Dong, Arvind F. Gupta, Samuel Halverson, Suzanne Hawley, Leslie Hebb, Rae HolcombAdam Kowalski, Jessica Libby-Roberts, Andrea S.J. Lin, Michael W. McElwain, Joe P. Ninan, Cristobal Petrovich, Arpita Roy, Christian Schwab, Ryan C. Terrien, Jason T. Wright

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


TOI-2076 b is a sub-Neptune-sized planet (R = 2.39 ± 0.10 R ) that transits a young (204 ± 50 MYr) bright (V = 9.2) K-dwarf hosting a system of three transiting planets. Using spectroscopic observations obtained with the NEID spectrograph on the WIYN 3.5 m Telescope, we model the Rossiter-McLaughlin effect of TOI-2076 b, and derive a sky-projected obliquity of λ = − 3 − 15 + 16 ° . Using the size of the star (R = 0.775 ± 0.015 R ), and the stellar rotation period (P rot = 7.27 ± 0.23 days), we estimate an obliquity of ψ = 18 − 9 + 10 ° (ψ < 34° at 95% confidence), demonstrating that TOI-2076 b is in a well-aligned orbit. Simultaneous diffuser-assisted photometry from the 3.5 m telescope at Apache Point Observatory rules out flares during the transit. TOI-2076 b joins a small but growing sample of young planets in compact multi-planet systems with well-aligned orbits, and is the fourth planet with an age ≲300 Myr in a multi-transiting system with an obliquity measurement. The low obliquity of TOI-2076 b and the presence of transit timing variations in the system suggest the TOI-2076 system likely formed via convergent disk migration in an initially well-aligned disk.

Original languageEnglish (US)
Article numberL41
JournalAstrophysical Journal Letters
Issue number2
StatePublished - Feb 1 2023

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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