The HD 191939 Exoplanet System is Well Aligned and Flat
Article
Article Title | The HD 191939 Exoplanet System is Well Aligned and Flat |
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ERA Journal ID | 1048 |
Article Category | Article |
Authors | Lubin, Jack, Petigura, Erik A., Van Zandt, Judah, Beard, Corey, Dai, Fei, Halverson, Samuel, Holcomb, Rae, Howard, Andrew W., Isaacson, Howard, Luhn, Jacob, Robertson, Paul, Rubenzahl, Ryan A., Stefánsson, Guđmundur, Winn, Joshua N., Brodheim, Max, Deich, William, Hill, Grant M., Gibson, Steven R., Holden, Bradford, Householder, Aaron, Laher, Russ R., Lanclos, Kyle, Payne, Joel, Roy, Arpita, Smith, Roger, Shaum, Abby P., Schwab, Christian and Walawende, Josh |
Journal Title | The Astronomical Journal |
Journal Citation | 168 (5) |
Article Number | 196 |
Number of Pages | 8 |
Year | 2024 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-6256 |
1538-3881 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/ad79ed |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/ad79ed |
Abstract | We report the sky-projected spin–orbit angle λ for HD 191939 b, the innermost planet in a six-planet system, using Keck/KPF to detect the Rossiter–McLaughlin (RM) effect. Planet b is a sub-Neptune with radius 3.4 ± 0.8 R⊕ and mass 10.0 ± 0.7 M⊕ with an RM amplitude <1 m s−1. We find the planet is consistent with a well-aligned orbit, measuring λ = 3fdg7 ± 5fdg0. Additionally, we place new constraints on the mass and period of the distant super-Jupiter, planet f, finding it to be 2.88 ± 0.26 MJ on a 2898 ± 152 days orbit. With these new orbital parameters, we perform a dynamical analysis of the system and constrain the mutual inclination of the nontransiting planet e to be smaller than 12° relative to the plane shared by the inner three transiting planets. Additionally, the further planet f is inclined off this shared plane, the greater the amplitude of precession for the entire inner system, making it increasingly unlikely to measure an aligned orbit for planet b. Through this analysis, we show that this system's wide variety of planets are all well-aligned with the star and nearly coplanar, suggesting that the system formed dynamically cold and flat out of a well-aligned protoplanetary disk, similar to our own solar system. |
Keywords | Exoplanet astronomy; Exoplanet dynamics |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 5101. Astronomical sciences |
Byline Affiliations | University of California Los Angeles, United States |
University of California Irvine, United States | |
University of Hawaii, United States | |
California Institute of Technology (Caltech), United States | |
Centre for Astrophysics | |
University of California Berkeley, United States | |
University of Amsterdam, Netherlands | |
Princeton University, United States | |
W. M. Keck Observatory, United States | |
University of California Santa Cruz, United States | |
Massachusetts Institute of Technology, United States | |
NASA Exoplanet Science Institute, United States | |
Astrophysics & Space Institute, United States | |
Macquarie University |
https://research.usq.edu.au/item/zv011/the-hd-191939-exoplanet-system-is-well-aligned-and-flat
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