J/A+A/658/A57 F-G-K stars activity indicators (Meunier+, 2022)
Relationship between Ca and H{alpha) chromospheric emission in F-G-K stars:
Indication of stellar filaments?
Meunier N., Kretzschmar M., Gravet R., Mignon L., Delfosse X.
<Astron. Astrophys. 658, A57 (2022)>
=2022A&A...658A..57M 2022A&A...658A..57M (SIMBAD/NED BibCode)
ADC_Keywords: Spectroscopy ; Stars, F-type ; Stars, G-type ; Stars, K-type ;
Magnetic fields
Keywords: stars: activity - stars: solar-type - stars: chromospheres -
techniques: spectroscopic - planetary systems
Abstract:
Different relationships between the Hα and CaII chromospheric
emissions have been reported in solar-type stars. In particular, the
time-series of emissions in these two lines are clearly
anti-correlated for a few percent of the stars, contrary to what is
observed on the Sun.
Our objective is to characterise these relationships in more detail
using complementary criteria, and to constrain the properties of
filaments and plages that are necessary to explain the observations.
We analysed the average level and variability of the Hα and CaII
emission for 441 F-G-K stars, paying particular attention to their
(anti-)correlations on both short and long timescales. We also
computed synthetic Hα and CaII time-series for different
assumptions of plage and filament properties and compared them with
the observations.
We were not able to find plage properties that, alone, are sufficient
to reproduce the observations at all timescales simultaneously, even
when allowing different Hα and CaII emission relationships for
different stars. We also specified the complex and surprising
relationship between the average activity levels of both indexes, in
particular for low-activity stars.
We conclude that plages alone are unlikely to explain the observed
variety of relationships between CaII and Hα emission, and that
the presence of other phenomena like filaments may help to reconcile
the models with observations.
Description:
List of stars studied in the paper (HARPS data from the ESO archive),
together with informations from various sources and outputs from our
analysis. The number of stars is 441.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 117 441 List of stars studied
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star name
13- 16 F4.2 mag B-V B-V coloud index from Simbad
18- 23 A6 --- SpType Spectral type from Simbad (1)
26- 29 I4 K Teff Effective temperature
33 I1 --- r_Teff Reference for Teff (2)
36- 40 F5.2 [-] [Fe/H] Metallicity
43 I1 --- r_[Fe/H] Reference for metallicity (2)
47- 49 I3 --- NBnights Number of nights used in the analysis
52- 55 I4 d Span Time span of the observations
58- 62 F5.2 --- logR'HK Averaged Mount Wilson R'HK index
65- 69 F5.2 --- logIHalpha Averaged Flux in Hα
71- 76 F6.3 --- Corrglob Global correlation
79- 83 F5.3 --- e_Corrglob 1-sigma uncertainty on global correlation
85- 86 I2 --- NBseasons Number of seasons
88- 92 F5.2 --- CorrLT ? Long-term correlation
97-100 F4.2 --- e_CorrLT ? 1-sigma uncertainty on long-term
correlation
102-103 I2 --- NBsubsets Number of subsets
105-109 F5.2 --- CorrST ? Short-term correlation
114-117 F4.2 --- e_CorrST ? 1-sigma uncertainty on short-term
correlation
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Note (2): references are the following:
1 = Sousa et al., 2008A&A...487..373S 2008A&A...487..373S
2 = Ramirez et al., 2014A&A...572A..48R 2014A&A...572A..48R Teff shifted by +5K
3 = Marsden et al., 2014MNRAS.444.3517M 2014MNRAS.444.3517M Teff shifted by +13K
4 = Gray et al., 2006AJ....132..161G 2006AJ....132..161G Teff shifted by +42K
5 = Holmberg et al., 2009A&A...501..941H 2009A&A...501..941H Teff shifted by -71K
6 = Ammons et al, 2006ApJ...638.1004A 2006ApJ...638.1004A Teff shifted by +61K
7 = Gaspar et al., 2016ApJ...826..171G 2016ApJ...826..171G
8 = Mortier et al., 2013A&A...551A.112M 2013A&A...551A.112M
9 = Soubiran et al., 2016A&A...591A.118S 2016A&A...591A.118S Teff shifted by +16K
Note (1): Luminosity classes are from Simbad, except for
HD163441 : Lorenzo-Oliveira et al., 2018A&A...619A..73L 2018A&A...619A..73L
HD78534 : Dos Santos et al., 2016A&A...592A.156D 2016A&A...592A.156D
HD141943 : Grandjean et al., 2020A&A...633A..44G 2020A&A...633A..44G
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Acknowledgements:
Nadege Meunier, nadege.meunier(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 13-Nov-2021