J/ApJ/828/47 Radial velocities of the Be star HR 2142 (Peters+, 2016)
The hot companion and circumbinary disk of the Be star HR 2142.
Peters G.J., Wang L., Gies D.R., Grundstrom E.D.
<Astrophys. J., 828, 47-47 (2016)>
=2016ApJ...828...47P 2016ApJ...828...47P (SIMBAD/NED BibCode)
ADC_Keywords: Radial velocities ; Stars, Be ; Binaries, spectroscopic ;
Spectra, ultraviolet
Keywords: binaries: spectroscopic; stars: emission-line, Be; stars: evolution;
stars: individual: HR 2142, HD 41335; subdwarfs
Abstract:
We present a spectroscopic investigation of the Be+sdO binary system
HR 2142 that is based upon large sets of ultraviolet observations from
the International Ultraviolet Explorer (IUE) and ground-based Hα
observations. We measured radial velocities for the Be star component
from these spectra and computed a revised orbit. In order to search
for the spectral signature of the hot subdwarf, we cross-correlated
the short wavelength end of each IUE spectrum with a model hot star
spectrum, and then we used the predicted Doppler shifts of the
subdwarf to shift-and-add all the cross-correlation functions to the
frame of the subdwarf. This merged function shows the weak signal from
the spectral lines of the hot star, and a best fit is obtained with a
mass ratio M2/M1=0.07±0.02, companion temperature
Teff≥43±5kK, projected rotational velocity Vsini<30km/s, and a
monochromatic flux ratio near 1170Å of f2/f1>0.009±0.001.
This hot subdwarf creates a one-armed spiral, tidal wake in the disk
of the Be star, and we present a circumbinary disk model that can
explain the occurrence of shell absorption lines by gas enhancements
that occur where gas crossing the gap created by the subdwarf strikes
the disk boundaries. The faint companion of HR 2142 may be
representative of a significant fraction of Be stars with undetected
former mass donor companion stars.
Description:
Radial velocity measurements were made using the set of spectra
summarized in Table 1.
The main focus of this work is a set of 88 high resolution, SWP HIRES
FUV spectra acquired over the lifetime of the International
Ultraviolet Explorer (IUE) observatory. These were downloaded from
MAST and resampled.
We also collected a set of 49 LWR and LWP near-UV spectra that were
used to inspect the orbital variations in the MgII2796,2803 feature.
The UV spectra were supplemented with a large collection of Hα
spectra that we secured with the KPNO Coude Feed telescope and that
were obtained by amateur astronomers participating in the Be Star
Spectra database project (Pollmann 2007IBVS.5778....1P 2007IBVS.5778....1P; Neiner et al.
2011AJ....142..149N 2011AJ....142..149N).
Objects:
------------------------------------------------
RA (ICRS) DE Designation(s)
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06 04 13.50 -06 42 32.2 HR 2142 = HD 41335
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 65 5 Spectroscopic observations of HR 2142
table2.dat 40 271 Be star radial velocities
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See also:
III/254 : Radial Velocities with Astrometric Data. II. (Kharchenko+, 2007)
III/244 : Catalog of Stellar Rotational Velocities (Glebocki+ 2005)
J/A+A/595/A132 : Be star rotational velocities distribution (Zorec+, 2016)
J/A+A/546/A61 : Radial velocities for XHIP catalogue (de Bruijne+, 2012)
J/A+A/440/305 : Fundamental param. of fast-rotating B stars (Fremat+, 2005)
J/ApJ/616/562 : Rotational velocities in binaries (Abt+, 2004)
J/ApJ/573/359 : Rotational velocities of B stars from BSC (Abt+, 2002)
J/A+A/368/912 : Polarization & rotational velocities of Be stars (Yudin, 2001)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 --- Seq [1/5] Observation Code
3- 10 A8 --- Source Telescope/Instrument/Satellite used
12- 13 I2 --- Nsp [8/88] Number of spectra
15 A1 --- l_R1 Limit flag on R1
16- 20 I5 --- R1 Spectral resolving power, λ/Δλ
or lower range of R if R2 exists
21 A1 --- --- [-]
22- 26 I5 --- R2 ? Upper range of spectral resolving power,
λ/Δλ
28- 31 I4 0.1nm lam1 [1150/6563] Lower range of wavelength, in Angstrom
32 A1 --- --- [-]
33- 36 I4 0.1nm lam2 [1950/7140]? Upper range of wavelength, in Angstrom
37 A1 --- u_lam1 Uncertainty flag in lam1
39- 42 I4 yr Date1 Date of first observation in Besselian year
44- 47 I4 yr Date2 Date of last observation in Besselian year
49- 65 A17 --- Obs Observer(s)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d HJD Observation date, HJD-2400000
12 A1 --- f_HJD [d] d=Discrepant datum flag (1)
14- 18 F5.3 --- Phase Orbital Phase
20- 23 F4.1 km/s HRV [22.8/65.8] Heliocentric Radial Velocity
25- 28 F4.1 km/s e_HRV [0.5/36] Uncertainty in HRV, σ
30- 34 F5.1 km/s O-C [-19.1/16.8] O-C residual
36- 40 I5 --- ObsID [1/55943] Source (2)
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Note (1): Discrepant datum (flag=d) was assigned zero-weight in orbital
solution.
Note (2): Source row listed in Table 1 (Column "Seq") or IUE
short-wavelength-prime (SWP) detector number if greater than 5.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 05-Dec-2016