Obliquities of exoplanet host stars: Nineteen new and updated measurements, and trends in the sample of 205 measurements
Journal article, 2024
Measurements of the obliquities in exoplanet systems have revealed some remarkable architectures, some of which are very different from the Solar System. Nearly 200 obliquity measurements have been obtained through observations of the Rossiter McLaughlin (RM) effect. Here, we report on observations of 19 planetary systems that led to 17 clear detections of the RM effect and 2 less secure detections. After adding the new measurements to the tally, we used the entire collection of RM measurements to investigate four issues that have arisen in the literature. i) Does the obliquity distribution show a peak at approximately 90 ? We find tentative evidence that such a peak does exist when restricting attention to the sample of sub-Saturn planets and hot Jupiters orbiting F stars. ii) Are high obliquities associated with high eccentricities? We find the association to be weaker than previously reported, and that a stronger association exists between obliquity and orbital separation, possibly due to tidal obliquity damping at small separations. iii) How low are the lowest known obliquities? Among hot Jupiters around cool stars, we find the dispersion to be 1.4 ± 0.7, smaller than the 6 obliquity of the Sun, which serves as additional evidence for tidal damping. iv) What are the obliquities of stars with compact and flat systems of multiple planets? We find that they generally have obliquities lower than 10, with several remarkable exceptions possibly caused by wide-orbiting stellar or planetary companions.
Planet-star interactions
Planets and satellites: dynamical evolution and stability
Planets and satellites: formation
Author
Emil Knudstrup
Aarhus University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Simon Albrecht
Princeton University
Aarhus University
J. N. Winn
Princeton University
D. Gandolfi
University of Turin
J. J. Zanazzi
University of California
Carina Persson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
M. L. Marcussen
Aarhus University
A. Chontos
Princeton University
University of Hawaii
Marcelo Aron Fetzner Keniger
The University of Warwick
N. L. Eisner
Flatiron Institute
Allyson Bieryla
Harvard-Smithsonian Center for Astrophysics
H. Isaacson
University of California
A. W. Howard
California Institute of Technology (Caltech)
L.A. Hirsch
University of Toronto
F. Murgas
Instituto de Astrofísica de Canarias
University of La Laguna
Norio Narita
Instituto de Astrofísica de Canarias
University of Tokyo
National Institutes of Natural Sciences
Enric Palle
University of La Laguna
Instituto de Astrofísica de Canarias
Yugo Kawai
University of Tokyo
D. Baker
Austin College
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 690 A379Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202450627