J/A+A/628/A106 Radial velocity time series of EK Eridani (Bonanno+, 2019)
Acoustic oscillations and dynamo action in the G8 sub-giant EK Eri.
Bonanno A., Corsaro E., Del Sordo F., Palle P.L., Stello D., Hon M.
<Astron. Astrophys. 628, A106 (2019)>
=2019A&A...628A.106B 2019A&A...628A.106B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant; Stars, variable; Radial velocities ; Magnetic fields
Keywords: stars: activity - starspots - stars: rotation - asteroseismology -
magnetohydrodynamics (MHD) - stars: individual: EK Eri
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±3uHz in the first observing run and were able to
determine a large separation, Δν=16.430±22uHz. 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 α2{OMEGA} dynamo cannot be
excluded as the possible origin for the observed magnetic field.
Description:
Radial velocity time series of EK Eridani are presented. These data
were obtained using the Hertzsprung telescope, a node of the Stellar
Observations Network Group (SONG) network, located at the Observatorio
del Teide on Tenerife, Spain.
Objects:
--------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------
04 20 38.64 -06 14 45.6 EK Eri = HR 1362
--------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 50 312 Radial velocities of EK Eridani for 2017
table2.dat 50 478 Radial velocities of EK Eridani for 2018
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.10 d BJD Barycentric Julian Date
19- 34 F16.6 m/s BRV Barycentric corrected radial velocity (1)
35- 50 F16.6 m/s e_BRV Uncertainty on RV (2)
--------------------------------------------------------------------------------
Note (1): Radial velocities are shifted relative to zero.
Note (2): This is the uncertainty derived and assigned by the authors to each
radial velocity point.
--------------------------------------------------------------------------------
History:
From Enrico Corsaro, enrico.corsaro(at)inaf.it
Acknowledgements:
These data were obtained 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 Astrofisica de Canarias. This work has been funded by the
European Union's Horizon 2020 research and innovation program under
the Marie Sklodowska-Curie grant agreement No. 664931.
(End) Patricia Vannier [CDS] 02-Aug-2019