J/AJ/167/268 Line broadening parameters in 22 RR Lyrae (Sneden+, 2024)
Variations in Line Profiles of Atomic Transitions in RR Lyrae Stars.
Sneden C., Preston G.W.
<Astron. J., 167, 268 (2024)>
=2024AJ....167..268S 2024AJ....167..268S
ADC_Keywords: Stars, variable; Line Profiles; Optical
Keywords: RRab variable stars ; RRc variable stars ; Stellar abundances
; Stellar atmospheres
Abstract:
We have investigated the absorption shapes of atomic lines and
Hα in RR-Lyrae stars. We used the database of high-resolution
spectra gathered with the Las Campanas Observatory du Pont Telescope,
analyzing a set of about 2700 short exposure spectra of 17 RRab and 5
RRc variables. To increase the signal-to-noise ratio of the spectra
for each star, we first coadded spectra in small photometric phase
bins, and then coadded metallic line profiles in velocity space. The
resulting line absorption shapes vary with photometric phase in a
consistent manner for all RRab stars, while exhibiting no obvious
phase-related variations for the RRc stars. We interpret these line
profile variations in terms of velocity gradients in the photospheric
layers that produce absorption line profiles. The Hα profiles
are much broader, indicative of shock temperatures of order 100000K.
Description:
From 2006 to 2014 we gathered more than 5400 RR-Lyrae spectra with the
Las Campanas Observatory du Pont Telescope Echelle Spectrograph. In
this work we use the database of several thousand du Pont echelle
spectra of RR Lyrae stars. The spectra have resolving power R=27000 at
5000AA.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 58 368 Observed line broadening parameters
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See also:
J/ApJS/194/38 : Radial velocities of 11 field RR Lyrae (For+, 2011)
J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)
J/ApJ/782/59 : Abundances 8 RR Lyrae subclass C variable stars (Govea+, 2014)
J/ApJ/848/68 : Abundances & RVs of stable & Blazhko RRc stars (Sneden+, 2017)
J/AJ/155/45 : Metal-rich RRc stars in Carnegie RRLyrae Survey (Sneden+, 2018)
J/AJ/157/153 : Atomic lines in spectra of RRLyrae & RHB stars (Preston+, 2019)
J/ApJ/919/85 : Field RR Lyrae as Gal. probes. V. RVC templates (Braga+, 2021)
J/ApJ/919/85 : Field RR Lyrae as Gal. probes. V. RVC templates (Braga+, 2021)
J/ApJ/908/20 : On use field RR Lyrae as galactic probes. II. (Crestani+, 2021)
J/ApJ/914/10 : Field RRLyrae as Gal. probes. III. Abundances (Crestani+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Star Star name
17- 21 F5.3 --- Phase [0.004/1] Pulsational phase
23- 24 I2 --- Lines [7/78] Number of absorption lines in mean profile
26- 30 F5.1 km/s VB50 [-18.6/-4.0] Blue velocity width at 0.50 of continuum
32- 35 F4.1 km/s VR50 [4.2/28.2] Red velocity width at 0.50 of continuum
37- 41 F5.1 km/s VB85 [-34.0/-9.2] Blue velocity width at 0.85 of continuum
43- 46 F4.1 km/s VR85 [9.4/55.0] Red velocity width at 0.85 of continuum
48- 52 F5.2 --- mu50 [-0.51/0.91] Skew at 0.50 of continuum
54- 58 F5.2 --- mu85 [-0.36/1.51] Skew at 0.85 of continuum
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 14-Jun-2024