J/MNRAS/532/563 Solar-type stars Halpha line (Souza dos Santos+, 2024)
Fine structure of the age-chromospheric activity relation in solar-type stars.
II. Hα line
Souza dos Santos P.V., Porto de Mello G.F., Costa-Bhering E.,
Lorenzo-Oliveira D., Almeida-Fernandes F., Dutra-Ferreira L., Ribas I.
<Mon. Not. R. Astron. Soc. 532, 563-576 (2024)>
=2024MNRAS.532..563S 2024MNRAS.532..563S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, F-type ; Stars, G-type ; Stars, K-type ; Stars, ages ;
Spectroscopy ; Photometry, H-alpha
Keywords: techniques: spectroscopic - stars: activity - stars: atmospheres -
stars: chromospheres - stars: solar-type - solar neighbourhood
Abstract:
Excess chromospheric emissions within deep photospheric lines are
effective proxies of stellar magnetism for FGK stars. This emission
decays with stellar age and is a potential determinant of this
important stellar quantity. We report absolutely calibrated Hα
chromospheric fluxes for 511 solar-type stars in a wide interval of
precisely determined masses, [Fe/H], ages, and evolution states from
high S/N, moderately high-resolution spectra. The comparison of Hα
and H+K chromospheric fluxes reveals a metallicity bias (absent from
Hα) affecting Ca II H+K fluxes thereby metal-rich stars with deep
line profiles mimic low chromospheric flux levels, and vice versa for
metal-poor stars. This bias blurs the age-activity relation,
precluding age determinations for old, inactive stars unless mass and
[Fe/H] are calibrated into the relation. The H+K lines being the most
widely studied tool to quantify magnetic activity in FGK stars, care
should be exercised in its use whenever wide ranges of mass and [Fe/H]
are involved. The Hα age-activity-mass-metallicity calibration
appears to be in line with the theoretical expectation that (other
parameters being equal) more massive stars possess narrower convective
zones and are less active than less massive stars, while more
metal-rich stars have deeper convective zones and appear more active
than metal-poorer stars. If regarded statistically in tandem with
other age diagnostics, Hα chromospheric fluxes may be suitable to
constrain ages for FGK stars with acceptable precision.
Description:
Our data consists of spectra of 511 stars of F, G, and K spectral
types, main sequence dwarfs and subgiants, and the vast majority of
stars part of the solar neighbourhood (distances less than 50 parsecs
to the Sun).
We determined the absolute Hα total and purely chromospheric
fluxes for 511 solar-type stars spanning a wide interval of precisely
determined masses, metallicities, ages, and states of evolution
through the use of modern model atmospheres and spectra of high S/N
ratio and moderately high resolution.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 53 510 Atmospheric parameters collected from the
literature and the final values used in this
paper for the sample stars
refs.dat 176 41 References
table4.dat 86 511 Bolometric correction and magnitude, luminosity,
radius, mass and age for the sample stars
table5.dat 30 511 Final total and purely chromospheric fluxes
for the sample stars
table10.dat 45 336 Chromospheric ages for the sample stars
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See also:
J/ApJ/839/94 : Abundances of solar twins from Keck/HIRES (Bedell+, 2017)
J/A+A/619/A73 : Solar twins age-chromospheric activity
(Lorenzo-Oliveira+, 2018)
J/MNRAS/529/2946 : Abundance catalogue of solar twins in GALAH (Walsen+, 2024)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Star name
11- 14 I4 K Tefflit ?=- Effective temperature compiled from
the literature
16- 20 F5.2 [-] [Fe/H]lit Iron to hydrogen abundance ratio compiled
from the literature
22- 25 F4.2 [cm/s2] logglit ?=- Surface gravity compiled from
the literature
27- 28 A2 --- r_Tefflit Reference of the atmospheric parameters
compiled, in refs.dat file
30- 33 I4 K Teff Effective temperature adopted in this work
35- 37 I3 K e_Teff ? Effective temperature error
39- 43 F5.2 [-] [Fe/H] Iron to hydrogen abundance ratio
adopted in this work
45- 48 F4.2 [cm/s2] logg Surface gravity adopted in this work
50- 53 F4.2 [cm/s2] e_logg Surface gravity error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Ref Reference code
4- 22 A19 --- BibCode BibCode
24- 45 A22 --- Aut Author's name
47-176 A130 --- Com Comments
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Star name (including Sun)
11- 16 A6 mag BC Bolometric correction
18- 22 F5.3 mag Mbol Bolometric magnitude
24- 28 F5.3 mag e_Mbol Bolometric magnitude error
30- 35 F6.3 Lsun Lum Luminosity
37- 41 F5.3 Lsun e_Lum Luminosity error
43- 47 F5.3 Rsun Rad Radius
49- 53 F5.3 Rsun e_Rad Radius error
55- 59 F5.3 Msun Mass Mass
61- 65 F5.3 Msun e_Mass Mass error
67- 72 F6.3 Gyr Age ?=- Age
74- 78 F5.3 Gyr e_Age ?=- Age error (inferior)
80- 84 F5.3 Gyr E_Age ?=- Age error (superior)
86 A1 --- Note [*A] Note (1)
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Note (1): Note as follows:
* = Stars with ages determined by asteroseismology
A = stars that are members of young open clusters or stellar associations,
whose ages were taken from specific and more detailed works
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Star name (including Sun)
11- 16 F6.4 10+3W/m2 Ftotal Hα total absolute flux (M.erg/cm2/s)
18- 23 F6.4 10+3W/m2 Fchrom Hα chromospheric absolute flux
25- 30 F6.4 10+3W/m2 e_Fchrom Hα chromospheric absolute flux error
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Star name (including Sun)
11- 15 F5.3 Gyr AgeHa Hα chromospheric age
17- 21 F5.3 Gyr E_AgeHa Hα chromospheric age upper error
23- 27 F5.3 Gyr e_AgeHa Hα chromospheric age lower error
29- 33 F5.3 Gyr AgeHK HK chromospheric age
35- 39 F5.3 Gyr E_AgeHK Hα chromospheric age upper error
41- 45 F5.3 Gyr e_AgeHK Hα chromospheric age lower error
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Acknowledgements:
Paulo Vitor Souza dos Santos, paulovss.astro(at)gmail.com
References:
Lorenzo-Oliveira et al., Paper I 2016A&A...595A..11L 2016A&A...595A..11L
(End) Patricia Vannier [CDS] 18-Jun-2024