J/A+A/620/A85 Binary post-AGB stars radial velocities (Oomen+, 2018)
Orbital properties of binary post-AGB stars.
Oomen G.M., Van Winckel H., Pols O., Nelemans G., Escorza A., Manick R.,
Kamath D., Waelkens C.
<Astron. Astrophys. 620, A85 (2018)>
=2018A&A...620A..85O 2018A&A...620A..85O (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: stars: AGB and post-AGB - binaries: spectroscopic -
circumstellar matter
Abstract:
Binary post-asymptotic giant branch (post-AGB) stars are thought to be
the products of a strong but poorly-understood interaction during the
AGB phase. The aim of this contribution is to update the orbital
elements of a sample of galactic post-AGB binaries observed in a
long-term radial-velocity monitoring campaign, by analysing these
systems in a homogeneous way. Radial velocities are computed from high
signal-to-noise spectra by use of a cross-correlation method. The
radial-velocity curves are fitted by using both a least-squares
algorithm and a Nelder-Mead simplex algorithm. We use a Monte Carlo
method to compute uncertainties on the orbital elements. The resulting
mass functions are used to derive a companion mass distribution by
optimising the predicted to the observed cumulative mass-function
distributions, after correcting for observational bias. As a result,
we derive and update orbital elements for 33 galactic post-AGB
binaries, among which 3 are new orbits. The orbital periods of the
systems range from 100 to about 3000 days. Over 70 percent (23 out of
33) of our binaries have significant non-zero eccentricities ranging
over all periods. Their orbits are non-circular despite the fact that
the Roche-lobe radii are smaller than the maximum size of a typical
AGB star and tidal circularisation should have been strong when the
objects were on the AGB. We derive a distribution of companion masses
that is peaked around 1.09M☉ with a standard deviation of
0.62M☉. The large spread in companion masses highlights the
diversity of post-AGB binary systems. Post-AGB binaries are often
chemically peculiar, showing in their photospheres the result of an
accretion process of circumstellar gas devoid of refractory elements.
We find that only post-AGB stars with high effective temperatures
(>5500K) in wide orbits are depleted in refractory elements,
suggesting that re-accretion of material from a circumbinary disc is
an ongoing process. It appears, however, that depletion is inefficient
for the closest orbits irrespective of the actual surface temperature.
Description:
We investigated the orbital properties of galactic post-AGB binaries
by performing a large radial velocity monitoring campaign with the
HERMES spectrograph mounted on the Mercator Telescope. This data is
supplemented with radial velocity data obtained with several European
Southern Observatory (ESO) telescopes. We fitted the orbits of 33
post-AGB binaries.
We present the radial velocity measurements for all 33 objects. The
catalogues contain the dates of the measurements, as well as the
radial velocities themselves together with their uncertainties. The
dates are presented in Heliocentric Julian Dates (HJD), while the unit
of radial velocity (RV) is km/s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 114 33 Updated orbital elements
rv/* . 33 Individual radial velocity curves
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See also:
J/A+A/597/A129 : Galactic RV Tauri stars velocities (Manick+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Sequential number
4- 18 A15 --- Name Star name
20- 27 F8.3 d Per Period
29- 35 F7.3 d e_Per rms uncertainty on Per
37- 41 F5.3 --- Ecc Eccentricity
43- 47 F5.3 --- e_Ecc rms uncertainty on Ecc
49- 57 F9.1 d T0 ?=- Time of periastron passage
59- 63 F5.1 d e_T0 ? rms uncertainty on T0
65- 69 F5.1 deg omega ?=- Argument of periastron
71- 74 F4.1 deg e_omega ? rms uncertainty on omega
76- 80 F5.2 km/s K1 K1 velocity
82- 85 F4.2 km/s e_K1 rms uncertainty on K1
86- 92 F7.2 km/s gamma gamma velocity
94- 97 F4.2 km/s e_gamma rms uncertainty on gamma
99-101 A3 --- Ref References (1)
103-114 A12 --- FileName Name of the file with RV data in subdirectory
rv
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Note (1): References as follows:
1 = Waters et al. (1993A&A...269..242W 1993A&A...269..242W)
2 = Van Winckel et al. (1998A&A...336L..17V 1998A&A...336L..17V)
3 = Kodaira et al. (1970ApJ...159..485K 1970ApJ...159..485K)
4 = Gorlova et al. (2012A&A...542A..27G 2012A&A...542A..27G)
5 = Manick et al. (2017, Cat. J/A+A/597/A129)
6 = Waelkens et al. (1996A&A...314L..17W 1996A&A...314L..17W)
7 = Van Winckel et al. (1995A&A...293L..25V 1995A&A...293L..25V)
8 = Hrivnak et al. (2008, Cat. J/AJ/136/1557)
9 = Van Winckel et al. (2000IAUS..177..285V 2000IAUS..177..285V)
10 = De Smedt et al. (2016, Cat. J/A+A/587/A6)
11 = Waelkens et al. (1991A&A...242..433W 1991A&A...242..433W)
12 = Van Winckel et al. (2009A&A...505.1221V 2009A&A...505.1221V)
13 = Gorlova et al. (2015MNRAS.451.2462G 2015MNRAS.451.2462G)
14 = Maas et al. (2002A&A...386..504M 2002A&A...386..504M)
15 = Gonzalez & Wallerstein (1996MNRAS.280..515G 1996MNRAS.280..515G)
16 = Pollard et al. (2006MmSAI..77..527P 2006MmSAI..77..527P)
17 = Gielen et al. (2008A&A...490..725G 2008A&A...490..725G)
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Byte-by-byte Description of file: rv/*
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian Date
17- 24 F8.3 km/s RV Radial velocity or cleaned radial velocities
for AC Her, DY Ori, EP Lyr, HP Lyr, U Mon
IRAS 08544-4431, IRAS 17038-4815 and TW Cam (1)
29- 34 F6.3 km/s e_RV Uncertainty on radial velocity (2)
37- 44 F8.3 km/s RVr ? Raw radial velocity for
AC Her, IRAS 19157-0247 and U Mon
49- 54 F6.3 km/s e_RVr ? Uncertainty on radial velocity (2)
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Note (1): For DY Ori, EP Lyr, HP Lyr, IRAS 09144-4933, IRAS 17038-4815 and
TW Cam, we provide cleaned data from (Manick et al., 2017A&A...597A.129M 2017A&A...597A.129M,
Cat. J/A+A/597/A129). Raw data for these objects is available at CDS.
Note (2): For AC Her, DY Ori, EP Lyr, HP Lyr, U Mon IRAS 08544-4431,
IRAS 17038-4815 and TW Cam, we assume the measurement uncertainty remains
the same after cleaning the radial velocities from pulsations.
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Acknowledgements:
Glenn-Michael Oomen, glennmichael.oomen(at)kuleuven.be
(End) Glenn-Michael Oomen [KU Leuven], Patricia Vannier [CDS] 19-Oct-2018