The First Spin-Orbit Obliquity of an M dwarf/brown dwarf system: an eccentric and aligned TOI-2119 b
Year: 2024
Type: article
Abstract: ABSTRACT 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 ($T_{\rm {eff}}$ = 3553 K). It has a mass of 64.4 M$_{\rm {J}}$ and radius of 1.08 R$_{\rm {J}}$, 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 $\lambda =-0.8\pm 1.1^\circ$ and a three-dimensional obliquity of $\psi =15.7\pm 5.5^\circ$. Additionally, we spatially resolve the stellar surface of TOI-2119 utilizing the Reloaded Rossiter–McLaughlin technique to determine the projected star–planet obliquity as $\lambda =1.26 \pm 1.3^{\circ }$. Both of these results agree within $2\sigma$ 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.
Authors: Lauren Doyle, Caleb I Cañas, Jessica E Libby-Roberts, Heather M Cegla, Guðmundur K Stefánsson, David Anderson, David J Armstrong, Chad Bender, Daniel Bayliss, Theron W Carmichael, Sarah Casewell, Shubham Kanodia, Marina Lafarga, Andrea S J Lin, Suvrath Mahadevan, Andy Monson, Paul Robertson, Dimitri Veras
Institutions: University of Warwick, Goddard Space Flight Center, Pennsylvania State University, University of Amsterdam, Universidad Católica del Norte, University of Arizona, University of Hawaiʻi at Mānoa, University of Hawaii System, University of Leicester, Carnegie Institution for Science, Earth and Planets Laboratory, University of California, Irvine
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,012
Awards: G2269359191, G3293336813, G3660363561, G4039484093, THE TRANSITING EXOPLANET SURVEY SATELLITE (TESS) SET TO LAUNCH IN MARCH WILL PERFORM A TWO-YEAR ALL-SKY SURVEY WITH THE PRIMARY GOAL OF DETECTING SMALL NEPTUNE AND EARTH-LIKE ANALOGUES AROUND BRIGHT NEARBY STARS. THE RESULTING SET OF EXTRASOLAR PLANETS WILL SERVE AS TARGETS FOR NASAS JAMES WEBB SPACE TELESCOPE (JWST) TO OBSERVE AND CHARACTERIZE THEIR ATMOSPHERES. THIS PROPOSAL WILL CREATE A LARGE GROUND-BASED HIGH-PRECISION SPECTROSCOPIC FOLLOW-UP PROGRAM TO ROBUSTLY VET TESS OBJECTS OF INTEREST (TOIS). TOIS ARE SYSTEMS WHICH SHOW A TRANSIT AND MAY BE GENUINE EXOPLANETS. WHILE THE TESS TEAM AND THE ASTROPHYSICAL COMMUNITY HAVE DEVELOPED SOME IDEAS FOR VETTING THIS PROPOSAL GREATLY COMPLEMENTS THE EXISTING TOOLS BY BRINGING IN NEW OBSERVATIONAL INSTRUMENTS ADEPT FOR CLASSIFYING AND DYNAMICALLY CHARACTERIZING TOIS. THIS PROPOSAL WILL USE THE APACHE POINT OBSERVATORY GALAXY EVOLUTION EXPERIMENT (APOGEE) SPECTROGRAPH ON THE SLOAN FOUNDATION 2.5-METER TELESCOPE THE HABITABLE ZONE PLANET FINDER (HPF) ON THE HOBBY-EBERLY TELESCOPE AND THE NASA/NSF SPONSORED NNEXPLORE EXOPLANET INVESTIGATIONS WITH DOPPLER SPECTROSCOPY (NEID) SPECTROGRAPH ON THE WIYN TELESCOPE. APOGEE IS CAPABLE OF OBSERVING 300 STARS SIMULTANEOUSLY AT A PRECISION NECESSARY TO CONFIRM IF A TOI IS AN EXOPLANET OR AN ASTROPHYSICAL FALSE POSITIVE. IT HAS CURRENTLY OBSERVED OVER 70 000 TESS STARS MOST WITH MULTIPLE OBSERVATIONS. HPF AND NEID CAN ONLY OBSERVE ONE TARGET BUT AT THE PRECISION NECESSARY TO DERIVE PRECISE EXOPLANETS MASSES. APOGEE DATA WILL CULL A LARGE NUMBER OF TOIS TO DEFINE A SUBSET OF TESS STARS HOSTING TRUE PLANETS IN NEED OF FURTHER CHARACTERIZATION BY HPF AND NEID. THE END PRODUCT IS A SUBSET OF TOIS WITH PRECISE DYNAMICAL MASSES AND RADII THAT CAN BE OBSERVED BY JWST. THIS PROPOSAL IS DIRECTLY ALIGNED WITH THE THEME OF EXOPLANET EXPLORATION WITHIN THE SOLICITATION AND THE BROADER GOALS OF NASA TO DISCOVER AND STUDY PLANETS AROUND OTHER STARS AND EXPLORE WHETHER THEY COULD HARBOR LIFE. THERE IS A DIRECT APPLICATION TO THE SUCCESS OF TESS AND JWST TWO CURRENT NASA MISSIONS BY PROVIDING A SET OF VERIFIED EXOPLANETS WITH PRECISE MASSES AND RADII. FUTURE PROGRAMS SUCH AS THE PROPOSED MISSIONS CONTRIBUTION TO THE ATMOSPHERIC REMOTE-SENSING EXOPLANET LARGE-SURVEY SPECTROSCOPY OF EXOPLANETS (CASE) OR FAST INFRARED EXOPLANET SPECTROSCOPY SURVEY EXPLORER (FINESSE) WHICH ARE DESIGNED TO EXPLORE THE ATMOSPHERE OF CONFIRMED EXOPLANETS WILL ALSO BENEFIT FROM THE RESULTS FROM THIS PROPOSAL BY CONSERVING LIMITED OBSERVATION TIME FOR THE HIGHEST PRIORITY PLANETS
OpenAlex ID: W4405970323