J/A+A/597/A129 Galactic RV Tauri stars velocities (Manick+, 2017)
Establishing binarity amongst Galactic RV Tauri stars with a disc.
Manick R., Van Winckel H., Kamath D., Hillen M., Escorza A.
<Astron. Astrophys. 597, A129 (2017)>
=2017A&A...597A.129M 2017A&A...597A.129M (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: stars: variables: Cepheids - binaries: spectroscopic -
stars: AGB and post-AGB - circumstellar matter - stars: distances -
stars: chemically peculiar
Abstract:
Over the last few decades it has become more evident that binarity is
a prevalent phenomenon amongst RV Tauri stars with a disc. This study
is a contribution to comprehend the role of binarity upon late stages
of stellar evolution.
In this paper we determine the binary status of six Galactic RV Tauri
stars, namely DY Ori, EP Lyr, HP Lyr, IRAS 17038-4815, IRAS
09144-4933, and TW Cam, which are surrounded by a dusty disc. The
radial velocities are contaminated by high-amplitude pulsations. We
disentangle the pulsations from the orbital signal in order to
determine accurate orbital parameters. We also place them on the HR
diagram, thereby establishing their evolutionary nature. We used
high-resolution spectroscopic time series obtained from the HERMES and
CORALIE spectrographs mounted on the Flemish Mercator and Swiss
Leonhard Euler Telescopes, respectively. An updated ASAS/AAVSO
photometric time series is analysed to complement the spectroscopic
pulsation search and to clean the radial velocities from the
pulsations. The pulsation-cleaned orbits are fitted with a Keplerian
model to determine the spectroscopic orbital parameters. We also
calibrated a PLC relationship using type II Cepheids in the LMC and
apply the relation to our Galactic sample to obtain accurate distances
and hence luminosities.
All six of the Galactic RV Tauri stars included in this study are
binaries with orbital periods ranging between ∼650 and 1700 days
and with eccentricities between 0.2 and 0.6. The mass functions range
between 0.08 to 0.55M☉ which points to an unevolved low-mass
companion. In the photometric time series we detect a long-term
variation on the timescale of the orbital period for IRAS
17038-4815, IRAS 09144-4933, and TW Cam. Our derived stellar
luminosities indicate that all except DY Ori and EP Lyr are post-AGB
stars. DY Ori and EP Lyr are likely examples of the recently
discovered dusty post-RGB stars. The orbital parameters strongly
suggest that the evolution of these stars was interrupted by a strong
phase of binary interaction during or even prior to the AGB. The
observed eccentricities and long orbital periods among these stars
provide a challenge to the standard theory of binary evolution.
Description:
We present the original radial velocities obtained at the Mercator and
Swiss Leonhard Telescopes, together with the pulsation-cleaned radial
velocities. The errors in the pulsation-cleaned radial velocities are
assumed to be the same as in the ones in the original data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 50 6 List of studied stars
dy_ori.dat 31 71 Original and cleaned RVs for DY ori
ep_lyr.dat 31 58 Original and cleaned RVs for EP Lyr
hp_lyr.dat 31 50 Original and cleaned RVs for HP Lyr
i09144.dat 31 74 Original and cleaned RVs for IRAS 09144
i17038.dat 31 75 Original and cleaned RVs for IRAS 17038
tw_cam.dat 31 87 Original and cleaned RVs for TW Cam
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Star name
17- 18 I2 h RAh Simbad Rigth ascension (J2000)
20- 21 I2 min RAm Simbad Rigth ascension (J2000)
23- 27 F5.2 s RAs Simbad Rigth ascension (J2000)
29 A1 --- DE- Simbad Declination sign (J2000)
30- 31 I2 deg DEd Simbad Declination (J2000)
33- 34 I2 arcmin DEm Simbad Declination (J2000)
36- 39 F4.1 arcsec DEs Simbad Declination (J2000)
41- 50 A10 --- FileName Name of the file with velocities
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Byte-by-byte Description of file: ??_???.dat i[01]*.dat
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Bytes Format Units Label Explanations
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1- 10 F10.2 d JD Julian date
12- 18 F7.2 km/s RV Original radial velocities
20- 26 F7.2 km/s RVc Pulsation-cleaned radial velocities
28- 31 F4.2 km/s e_RV Error in the pulsation cleaned RV assumed
to be same as the original RV
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Acknowledgements:
Rajeev Manick, rajeevmnck(at)gmail.com
(End) Rajeev Manick [KU Leuven], Patricia Vannier [CDS] 21-Dec-2016