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