Acoustic oscillations and dynamo action in the G8 sub-giant EK Eridani

Journal
Date Issued
2019
Author(s)
•
•
Del Sordo, F.
•
Pallé, P. L.
•
Stello, D.
•
Hon, M.
DOI
Abstract
We present further evidence of acoustic oscillations in the slowly rotating overactive G8 sub-giant EK Eri. This star was observed with the 1m Hertzsprung SONG telescope at the Observatorio del Teide for two different runs of 8 and 13 nights, respectively, that were separated by about a year. We determined a significant excess of power around νmax = 253 ± 3 μHz in the first observing run and were able to determine a large separation, ∆ν = 16.43 ± 0.22 μHz. No significant excess of power was instead detected in a subsequent SONG observing season, as also supported by our analysis of the simultaneous TESS photometric observations. We propose a new amplitude-luminosity relation in order to account for the missing power in the power spectrum. Based on the evolutionary stage of this object, we argue that a standard α2Ω dynamo cannot be excluded as the possible origin for the observed magnetic field.

A table of the radial velocities is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/628/A106 Based on observations made with the Hertzsprung SONG telescope operated on the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias.

Volume
628
Start page
A106
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2019A&A...628A.106B
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

corsa.pdf

Description
PDF editoriale
Size

1.32 MB

Format

Adobe PDF

Checksum (MD5)

29cae25556e342dd83f3f07f419eb8fd