Asteroseismology of the Nearby K Dwarf σ Draconis Using the Keck Planet Finder and TESS

November 2024 • 2024ApJ...975..147H

Authors • Hon, Marc • Huber, Daniel • Li, Yaguang • Metcalfe, Travis S. • Bedding, Timothy R. • Ong, Joel • Chontos, Ashley • Rubenzahl, Ryan • Halverson, Samuel • García, Rafael A. • Kjeldsen, Hans • Stello, Dennis • Hey, Daniel R. • Campante, Tiago • Howard, Andrew W. • Gibson, Steven R. • Rider, Kodi • Roy, Arpita • Baker, Ashley D. • Edelstein, Jerry • Smith, Chris • Fulton, Benjamin J. • Walawender, Josh • Brodheim, Max • Brown, Matt • Chan, Dwight • Dai, Fei • Deich, William • Gottschalk, Colby • Grillo, Jason • Hale, Dave • Hill, Grant M. • Holden, Bradford • Householder, Aaron • Isaacson, Howard • Ishikawa, Yuzo • Jelinsky, Sharon R. • Kassis, Marc • Kaye, Stephen • Laher, Russ • Lanclos, Kyle • Lee, Chien-Hsiu • Lilley, Scott • McCarney, Ben • Miller, Timothy N. • Payne, Joel • Petigura, Erik A. • Poppett, Claire • Raffanti, Michael • Rockosi, Constance • Sanford, Dale • Schwab, Christian • Shaum, Abby P. • Sirk, Martin M. • Smith, Roger • Thorne, Jim • Valliant, John • Vandenberg, Adam • Wang, Shin Ywan • Wishnow, Edward • Wold, Truman • Yeh, Sherry • Baker, Ashley • Basu, Sarbani • Bedell, Megan • Cegla, Heather M. • Crossfield, Ian • Dressing, Courtney • Dumusque, Xavier • Knutson, Heather • Mawet, Dimitri • O'Meara, John • Stefánsson, Guđmundur • Teske, Johanna • Vasisht, Gautam • Wang, Sharon Xuesong • Weiss, Lauren M. • Winn, Joshua N. • Wright, Jason T.

Abstract • Asteroseismology of dwarf stars cooler than the Sun is very challenging owing to the low amplitudes and rapid timescales of oscillations. Here we present the asteroseismic detection of solar-like oscillations at 4-minute timescales ( νmax∼4300 μHz) in the nearby K dwarf σ Draconis using extreme-precision Doppler velocity observations from the Keck Planet Finder and 20 s cadence photometry from NASA's Transiting Exoplanet Survey Satellite. The star is the coolest dwarf star to date with both velocity and luminosity observations of solar-like oscillations, having amplitudes of 5.9 ± 0.8 cm s^‑1 and 0.8 ± 0.2 ppm, respectively. These measured values are in excellent agreement with established luminosity‑velocity amplitude relations for oscillations and provide further evidence that mode amplitudes for stars with T _eff < 5500 K diminish in scale following an (L/M)^1.5 relation. By modeling the star's oscillation frequencies from photometric data, we measure an asteroseismic age of 4.5 ± 0.9 (ran) ± 1.2 (sys) Gyr. The observations demonstrate the capability of next-generation spectrographs and precise space-based photometry to extend observational asteroseismology to nearby cool dwarfs, which are benchmarks for stellar astrophysics and prime targets for directly imaging planets using future space-based telescopes.

Links

• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ad76a9/pdf
• PREPRINT http://arxiv.org/abs/2407.21234
• ELECTR https://iopscience.iop.org/article/10.3847/1538-4357/ad76a9