TY - JOUR
T1 - The First Spin-Orbit Obliquity of an M dwarf/brown dwarf system
T2 - an eccentric and aligned TOI-2119 b
AU - Doyle, Lauren
AU - Cañas, Caleb I.
AU - Libby-Roberts, Jessica E.
AU - Cegla, Heather M.
AU - Stefánsson, Guðmundur K.
AU - Anderson, David
AU - Armstrong, David J.
AU - Bender, Chad
AU - Bayliss, Daniel
AU - Carmichael, Theron W.
AU - Casewell, Sarah
AU - Kanodia, Shubham
AU - Lafarga, Marina
AU - Lin, Andrea S.J.
AU - Mahadevan, Suvrath
AU - Monson, Andy
AU - Robertson, Paul
AU - Veras, Dimitri
N1 - Publisher Copyright:
© 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2025/2/1
Y1 - 2025/2/1
N2 - We report the first instance of an M dwarf/brown dwarf obliquity measurement for the TOI-2119 system using the Rossiter–McLaughlin effect. TOI-2119 b is a transiting brown dwarf orbiting a young, active early M dwarf (Teff = 3553 K). It has a mass of 64.4 MJ and radius of 1.08 RJ, with an eccentric orbit (e = 0.3) at a period of 7.2 d. For this analysis, we utilize NEID spectroscopic transit observations and ground-based simultaneous transit photometry from the Astrophysical Research Consortium and the Las Campanas Remote Observatory. We fit all available data of TOI-2119 b to refine the brown dwarf parameters and update the ephemeris. The classical Rossiter–McLaughlin technique yields a projected star–planet obliquity of λ = −0.8 ± 1.1◦ and a three-dimensional obliquity of ψ = 15.7 ± 5.5◦. Additionally, we spatially resolve the stellar surface of TOI-2119 utilizing the Reloaded Rossiter–McLaughlin technique to determine the projected star–planet obliquity as λ = 1.26 ± 1.3◦. Both of these results agree within 2σ and confirm the system is aligned, where TOI-2119 b joins an emerging group of aligned brown dwarf obliquities. We also probe stellar surface activity on the surface of TOI-2119 in the form of centre-to-limb variations as well as the potential for differential rotation. Overall, we find tentative evidence for centre-to-limb variations on the star but do not detect evidence of differential rotation.
AB - We report the first instance of an M dwarf/brown dwarf obliquity measurement for the TOI-2119 system using the Rossiter–McLaughlin effect. TOI-2119 b is a transiting brown dwarf orbiting a young, active early M dwarf (Teff = 3553 K). It has a mass of 64.4 MJ and radius of 1.08 RJ, with an eccentric orbit (e = 0.3) at a period of 7.2 d. For this analysis, we utilize NEID spectroscopic transit observations and ground-based simultaneous transit photometry from the Astrophysical Research Consortium and the Las Campanas Remote Observatory. We fit all available data of TOI-2119 b to refine the brown dwarf parameters and update the ephemeris. The classical Rossiter–McLaughlin technique yields a projected star–planet obliquity of λ = −0.8 ± 1.1◦ and a three-dimensional obliquity of ψ = 15.7 ± 5.5◦. Additionally, we spatially resolve the stellar surface of TOI-2119 utilizing the Reloaded Rossiter–McLaughlin technique to determine the projected star–planet obliquity as λ = 1.26 ± 1.3◦. Both of these results agree within 2σ and confirm the system is aligned, where TOI-2119 b joins an emerging group of aligned brown dwarf obliquities. We also probe stellar surface activity on the surface of TOI-2119 in the form of centre-to-limb variations as well as the potential for differential rotation. Overall, we find tentative evidence for centre-to-limb variations on the star but do not detect evidence of differential rotation.
UR - https://www.scopus.com/pages/publications/85215542681
UR - https://www.scopus.com/pages/publications/85215542681#tab=citedBy
U2 - 10.1093/mnras/stae2819
DO - 10.1093/mnras/stae2819
M3 - Article
AN - SCOPUS:85215542681
SN - 0035-8711
VL - 536
SP - 3745
EP - 3756
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -