Spinning up a Daze: TESS Uncovers a Hot Jupiter Orbiting the Rapid Rotator TOI-778

May 2023 • 2023AJ....165..207C

Authors • Clark, Jake T. • Addison, Brett C. • Okumura, Jack • Vach, Sydney • Errico, Adriana • Heitzmann, Alexis • Rodriguez, Joseph E. • Wright, Duncan J. • Clerté, Mathieu • Brown, Carolyn J. • Fetherolf, Tara • Wittenmyer, Robert A. • Plavchan, Peter • Kane, Stephen R. • Horner, Jonathan • Kielkopf, John F. • Shporer, Avi • Tinney, C. G. • Hui-Gen, Liu • Ballard, Sarah • Bowler, Brendan P. • Mengel, Matthew W. • Zhou, George • Lee, Annette S. • David, Avelyn • Heim, Jessica • Lee, Michele E. • Sevilla, Verónica • Zafar, Naqsh E. • Hinkel, Natalie R. • Allen, Bridgette E. • Bayliss, Daniel • Berberyan, Arthur • Berlind, Perry • Bieryla, Allyson • Bouchy, François • Brahm, Rafael • Bryant, Edward M. • Christiansen, Jessie L. • Ciardi, David R. • Ciardi, Krys N. • Collins, Karen A. • Dallant, Jules • Davis, Allen B. • Díaz, Matías R. • Dressing, Courtney D. • Esquerdo, Gilbert A. • Harre, Jan-Vincent • Howell, Steve B. • Jenkins, Jon M. • Jensen, Eric L. N. • Jones, Matías I. • Jordán, Andrés • Latham, David W. • Lund, Michael B. • McCormac, James • Nielsen, Louise D. • Otegi, Jon • Quinn, Samuel N. • Radford, Don J. • Ricker, George R. • Schwarz, Richard P. • Seager, Sara • Smith, Alexis M. S. • Stockdale, Chris • Tan, Thiam-Guan • Udry, Stéphane • Vanderspek, Roland • Günther, Maximilian N. • Wang, Songhu • Wingham, Geof • Winn, Joshua N.

Abstract • NASA's Transiting Exoplanet Survey Satellite (TESS) mission has been uncovering a growing number of exoplanets orbiting nearby, bright stars. Most exoplanets that have been discovered by TESS orbit narrow-line, slow-rotating stars, facilitating the confirmation and mass determination of these worlds. We present the discovery of a hot Jupiter orbiting a rapidly rotating ( $v\sin \,(i)=35.1\pm 1.0$ km s-1) early F3V-dwarf, HD 115447 (TOI-778). The transit signal taken from Sectors 10 and 37 of TESS's initial detection of the exoplanet is combined with follow-up ground-based photometry and velocity measurements taken from MINERVA-Australis, TRES, CORALIE, and CHIRON to confirm and characterize TOI-778 b. A joint analysis of the light curves and the radial velocity measurements yields a mass, a radius, and an orbital period for TOI-778 b of ${2.76}_{-0.23}^{+0.24}$ M J, 1.370 ± 0.043 R J, and ~4.63 days, respectively. The planet orbits a bright (V = 9.1 mag) F3-dwarf with M = 1.40 ± 0.05 M , R = 1.70 ± 0.05 R , and $\mathrm{log}g=4.05\pm 0.17$ . We observed a spectroscopic transit of TOI-778 b, which allowed us to derive a sky-projected spin-orbit angle of 18° ± 11°, consistent with an aligned planetary system. This discovery demonstrates the capability of smaller-aperture telescopes such as MINERVA-Australis to detect the radial velocity signals produced by planets orbiting broad-line, rapidly rotating stars.


IPAC Authors


Jessie Christiansen

Associate Scientist


David Ciardi

Senior Scientist