M. Lundkvist, H. Kjeldsen, T. R. Bedding, M. J. McCaughrean, R. P. Butler, D. Slumstrup, T. L. Campante, C. Aerts, T. Arentoft, H. Bruntt, C. Cardoso, F. Carrier, L. M. Close, J. Gomes da Silva, T. Kallinger, R. R. King, Y. Li, S. J. Murphy, J. L. Rørsted, D. Stello
Abstract
We have detected solar-like oscillations in the mid-K-dwarf epsilon Indi A, making it the coolest dwarf to have measured oscillations. The star is noteworthy for harboring a pair of brown dwarf companions and a Jupiter-type planet. We observed epsilon Indi A during two radial velocity campaigns, using the high-resolution spectrographs HARPS (2011) and UVES (2021). Weighting the time series, we computed the power spectra and established the detection of solar-like oscillations with a power excess located at 5265 ± 110 μHz—the highest frequency solar-like oscillations so far measured in any star. The measurement of the center of the power excess allows us to compute a stellar mass of 0.782 ± 0.023 M⊙ based on scaling relations and a known radius from interferometry. We also determine the amplitude of the peak power and note that there is a slight difference between the two observing campaigns, indicating a varying activity level. Overall, this work confirms that low-amplitude solar-like oscillations can be detected in mid-K-type stars in radial velocity measurements obtained with high-precision spectrographs.
Keywords
Asteroseismology; Radial velocity; K dwarf stars
The Astrophysical Journal
Volume 964, Number 2
2024 April
