J/AJ/165/70 GALEX photometric data for 193 ROSAT giant stars (Crandall+, 2023)
Correlations in Chromospheric and Coronal Activity Indicators of Giant Stars.
Crandall S., Smith G.H.
<Astron. J., 165, 70 (2023)>
=2023AJ....165...70C 2023AJ....165...70C
ADC_Keywords: Stars, giant; Photometry, ultraviolet; Optical; X-ray sources
Keywords: Late stellar evolution ; Giant stars ; X-ray stars ;
Ultraviolet astronomy
Abstract:
The main goal of this paper is to use ultraviolet photometry from the
Galaxy Evolution Explorer (GALEX) satellite to study chromospheric
activity among red giant and core-helium-burning (CHeB) stars.
Correlations are sought between several chromospheric and coronal
activity indicators for giants that were detected in soft X-rays by
the ROentgen SATellite. There is an evident correlation between
log(LXLbol) and log(FMgII/Fbol), where LX is the X-ray
luminosity and FMgII is the flux from MgIIh and k emission lines,
although there is substantial scatter. Using GALEX far-ultraviolet
(FUV) magnitudes, the relationship between an FUV-excess parameter (a
proxy for chromospheric and transition-region emission lines) and
X-ray luminosity is documented. Correlations found herein are not
strong, and may be linked to binarity. There is a varied range of FUV
emission among CHeB stars, indicating that giants in this phase may be
exhibiting differences or cycles in outer atmospheric activity.
Additionally, efforts were made to constrain a relationship between
excess FUV and near-ultraviolet emission and the projected surface
rotation velocity, vsini, of giants. No clear relationship was found.
Obscurities in this relationship may result from a spread in sini
inclinations, and/or too few stars with vsini>7km/s.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 52 193 GALEX data for a ROSAT giant star sample
--------------------------------------------------------------------------------
See also:
B/simbad : Simbad objects catalogue (M.Wenger 2000)
II/84 : 13-color photometry of 1380 bright stars (Johnson+ 1975)
II/97 : ANS UV Catalogue of Point Sources (Wesselius+ 1982)
II/122 : UBV Photoelectric Catalog; data 1953-1985 (Mermilliod 1987)
III/150 : Perkins Revised MK Types for the Cooler Stars (Keenan+ 1989)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/348/253 : Late type giants and supergiants in X-Ray (Maggio+, 1990)
J/A+AS/127/251 : Giants and supergiants ROSAT data (Huensch+ 1998)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/AJ/135/209 : Rot. & radial velocities 761 HIP giants (Massarotti+, 2008)
J/MNRAS/414/418 : Chromospheric Mg II h+k flux of evolved stars (Perez+, 2011)
J/MNRAS/422/2024 : X-ray-age relation & exoplanet evaporation (Jackson+, 2012)
J/A+A/616/A10 : 46 open clusters GaiaDR2 HR diag. (Gaia Collaboration, 2018)
J/ApJ/872/95 : GALEX & Gaia data APOGEE red clump stars (Mohammed+, 2019)
J/AJ/160/217 : 342 FGK-dwarfs ages using GALEX FUV mag (Crandall+, 2020)
J/AJ/160/12 : J, Ks, NUV emission of 133 red giant stars (Dixon+, 2020)
J/ApJ/902/114 : Stellar Xray activity I. Chandra, Gaia & GALEX (Wang+, 2020)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Source identifier
11- 15 F5.2 mag FUVmag [11.4/21.4] GALEX GR6/7 catalog FUV magnitude
17- 21 F5.2 mag Q [-9.04/8.22] FUV-excess parameter
23- 26 F4.2 mag e_FUVmag [0/0.4] Uncertainty in FUVmag
28- 31 F4.2 mag Gmag [2.22/7.06] Gaia EDR3 G band magnitude
33- 36 F4.2 mag e_Gmag [0/0.03] Uncertainty in Gmag
38- 41 F4.2 mag BPmag [3.22/7.51] Gaia EDR3 Blue passband magnitude
43- 46 F4.2 mag e_BPmag [0/0.5] Uncertainty in Bpmag
48- 52 F5.2 [-] LX/Lbol [-7.62/-3.9] log ROSAT X-ray to bolometric
luminosities
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 31-May-2023