Hunt for Starspots in HARPS Spectra of G and K Stars

Morris, Brett M.; Hoeijmakers, H. Jens; Kitzmann, Daniel; Demory, Brice-Olivier (2020). Hunt for Starspots in HARPS Spectra of G and K Stars. The astronomical journal, 160(1), p. 5. American Astronomical Society 10.3847/1538-3881/ab9365

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We present a method for detecting starspots on cool stars using the cross-correlation function (CCF) of high-resolution molecular spectral templates applied to archival high-resolution spectra of G and K stars observed with the High Accuracy Radial Velocity Planet Searcher (HARPS)/HARPS-N. We report nondetections of starspots on the Sun even when the Sun was spotted, the solar twin 18 Scorpii, and the very spotted Sun-like star HAT-P-11, suggesting that Sun-like starspot distributions will be invisible to the CCF technique, and should not produce molecular absorption signals that might be confused for signatures of exoplanet atmospheres. We detect strong TiO absorption in the T Tauri K-dwarfs LkCa 4 and AA Tau, consistent with significant coverage by cool regions. We show that despite the nondetections, the technique is sensitive to relatively small spot coverages on M dwarfs and large starspot areas on Sun-like stars.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Center for Space and Habitability (CSH)

UniBE Contributor:

Kitzmann, Daniel and Demory, Brice-Olivier

Subjects:

500 Science
500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0004-6256

Publisher:

American Astronomical Society

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

13 Apr 2021 14:39

Last Modified:

06 Jun 2021 02:30

Publisher DOI:

10.3847/1538-3881/ab9365

BORIS DOI:

10.48350/154806

URI:

https://boris.unibe.ch/id/eprint/154806

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