J 2025

Stellar obliquities of eight close-in gas giant exoplanets

ZAK, J.; H. M. J. BOFFIN; E. SEDAGHATI; A. BOCCHIERI; Z. BALKOOVA et. al.

Basic information

Original name

Stellar obliquities of eight close-in gas giant exoplanets

Authors

ZAK, J.; H. M. J. BOFFIN; E. SEDAGHATI; A. BOCCHIERI; Z. BALKOOVA; Marek SKARKA and P. KABATH

Edition

Astronomy & Astrophysics, EDP Sciences, 2025, 0004-6361

Other information

Language

English

Type of outcome

Article in a journal

Country of publisher

France

Confidentiality degree

is not subject to a state or trade secret

References:

URL

Organization

Přírodovědecká fakulta – Repository – Repository

DOI

http://dx.doi.org/10.1051/0004-6361/202452171

UT WoS

001414735800016

EID Scopus

2-s2.0-85217871028

Keywords in English

techniques: radial velocities; planets and satellites: atmospheres; planets and satellites: gaseous planets; planet-star interactions
Changed: 19/6/2025 00:50, RNDr. Daniel Jakubík

Abstract

V originále

The Rossiter- McLaughlin effect allows us to measure the projected stellar obliquity of exoplanets. From the spin-orbit alignment, planet formation and migration theories can be tested to improve our understanding of the currently observed exoplanetary population. Despite having the spin-orbit measurements for more than 200 planets, the stellar obliquity distribution is still not fully understood, warranting additional measurements to sample the full parameter space. We analyzed archival HARPS and HARPS-N spectroscopic transit time series of eight gas giant exoplanets on short orbits and derive their projected stellar obliquity λ. We report a prograde, but misaligned orbit for HAT-P-50b (λ = 41 - 9+10), possibly hinting at previous high-eccentricity migration given the presence of a close stellar companion. We measure sky-projected obliquities that are consistent with aligned orbits for the rest of the planets: WASP- 48b (λ = - 4 ± 4), WASP-59b (λ = 1 - 21+20), WASP-140 Ab (λ = - 1 ± 3), WASP-173 Ab (λ = 9 ± 5), TOI-2046b (λ = 1 ± 6), HAT-P-41 Ab (λ = - 4 - 6+5), and Qatar-4b (λ = - 13 - 19+15). We measure the true stellar obliquity ψfor four systems. We infer a prograde, but misaligned, orbit for TOI-2046b with ψ= 42- 8+10 deg. Additionally, ψ= 30 - 15+18 for WASP-140 Ab, ψ= 21 - 10+9 for WASP-173 Ab, and ψ= 32 - 13+14 for Qatar-4b. The aligned orbits are consistent with slow disk migration, ruling out violent events that would excite the orbits over the history of these systems. Finally, we provide a new age estimate for TOI-2046 of at least 700 Myr and for Qatar-4 of at least 350- 500 Myr, contradicting previous results.
Displayed: 18/7/2025 18:38