A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c

Daniel Huber, Timothy R. White, Travis S. Metcalfe, Ashley Chontos, Michael M. Fausnaugh, Cynthia S. K. Ho, Vincent Van Eylen, Warrick Ball, Sarbani Basu, Timothy R. Bedding, Othman Benomar, Diego Bossini, Sylvain Breton, Derek L. Buzasi, Tiago L. Campante, William J. Chaplin, Joergen Christensen-Dalsgaard, Margarida S. Cunha, Morgan Deal, Rafael A. Garcia, Antonio Garcia Munoz, Charlotte Gehan, Lucia Gonzalez-Cuesta, Chen Jiang, Cenk Kayhan, Hans Kjeldsen, Mia S. Lundkvist, Stephane Mathis, Savita Mathur, Mario J. P. F. G. Monteiro, Benard Nsamba, Jia Mian Joel Ong, Erika Pakstiene, Aldo M. Serenelli, Victor Silva Aguirre, Keivan G. Stassun, Dennis Stello, Sissel Norgaard Stilling, Mark Lykke Winther, Tao Wu, Thomas Barclay, Tansu Daylan, Maximilian N. Guenther, J. J. Hermes, Jon M. Jenkins, David W. Latham, Alan M. Levine, George R. Ricker, Sara Seager, Avi Shporer, Joseph D. Twicken, Roland K. Vanderspek, Joshua N. Winn

A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c
See arXiv version
17 pages (excluding references), 13 figures, 6 tables; submitted to AAS Journals


We present an analysis of the first 20-second cadence light curves obtained by the TESS space telescope during its extended mission. We find a precision improvement of 20-second data compared to 2-minute data for bright stars when binned to the same cadence (~10-25% better for T<~8 mag, reaching equal precision at T~13 mag), consistent with pre-flight expectations based on differences in cosmic ray mitigation algorithms. We present two results enabled by this improvement. First, we use 20-second data to detect oscillations in three solar analogs (gamma Pav, zeta Tuc and pi Men) and use asteroseismology to measure their radii, masses, densities and ages to ~1%, ~3%, ~1% and ~20% respectively, including systematic errors. Combining our asteroseismic ages with chromospheric activity measurements we find evidence that the spread in the activity-age relation is linked to stellar mass and thus convection-zone depth. Second, we combine 20-second data and published radial velocities to re-characterize pi Men c, which is now the closest transiting exoplanet for which detailed asteroseismology of the host star is possible. We show that pi Men c is located at the upper edge of the planet radius valley for its orbital period, confirming that it has likely retained a volatile atmosphere and that the “asteroseismic radius valley” remains devoid of planets. Our analysis favors a low eccentricity for pi Men c (<0.1 at 68% confidence), suggesting efficient tidal dissipation (Q/k <~ 2400) if it formed via high-eccentricity migration. Combined, these early results demonstrate the strong potential of TESS 20-second cadence data for stellar astrophysics and exoplanet science.

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