J/A+A/444/895 Spectroscopy of HD 45166 (Steiner+, 2005)
The qWR star HD 45166: I. Observations and system parameters
Steiner J.E., Oliveira, A.S.
<Astron. Astrophys. 444, 895 (2005)>
=2005A&A...444..895S 2005A&A...444..895S
ADC_Keywords: Binaries, spectroscopic ; Stars, Wolf-Rayet ; Spectroscopy ;
Equivalent widths ; Radial velocities
Keywords: techniques: spectroscopic - binaries: spectroscopic -
stars: Wolf-Rayet
Abstract:
The binary star HD 45166 has been observed since 1922 but its orbital
period has not yet been found. It is considered a peculiar Wolf-Rayet
star, and its assigned classification has varied. For this reason we
included the object as a candidate V Sge star and performed
spectroscopy in order to search for its putative orbital period.
High-resolution spectroscopic observations show that the spectrum, in
emission and in absorption, is quite rich. The emission lines have
great diversity of widths and profiles. The full widths at half
maximum vary from 70km/s for the weakest lines up to 370km/s for the
most intense ones. The Hydrogen and Helium lines are systematically
broader than the CNO lines. Assuming that HD 45166 is a double-line
spectroscopic binary, it present s an orbital period of
P=1.596±0.003-day, with an eccentricity of e=0.18±0.08. In
addition, a search for periodicity using standard techniques reveals
that the emission lines present at least two other periods, of 5 and 5
hour. The secondary star has a spectral type of B7 V and, therefore,
should have a mass of about M=4.8M☉. Given the radial velocity
amplitudes, we determined the mass of the hot (primary) star as
M=4.2±0.7M☉ and the inclination angle of the system,
i=0.77±0.09deg. As the eccentricity of the orbit is non zero, the
Roche lobes increase and decrease as a function of the orbital phase.
At periastron, the secondary star fills its Roche lobe. The distance
to the star has been re-determined as d=1.3±0.2kpc and a color
excess of E(B-V)=0.155±0.007 has been derived. This implies an
absolute B magnitude of -0.6 for the primary star and -0.7 for the B7
star. We suggest that the discrete absorption components (DACs)
observed in the ultraviolet with a periodicity similar to the orbital
period may be induced by periastron events.
Description:
Journal of observations of HD 45166 and its spectral lines
identifications and measurements are presented. The spectra were
obtained with the FEROS spectrograph and have high spectral resolution
(R=48000) and covers from 3700 to 8800Å. The spectral measurements
of each absorption and emission lines are the observed central
wavelength, the radial velocity in the heliocentric system, the
equivalent width and the FWHM.
Objects:
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RA (2000) DE Designation(s)
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06 26 19.2 +07 58 28 HD 45166 = BD+08 1332
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 51 12 Journal of observations
table3.dat 61 63 Strong absorption lines (Wlambda>0.02Å)
table4.dat 72 27 Weak absorption lines (Wlambda<0.02Å)
table5.dat 64 114 Emission lines
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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 A10 "YYYY/MM/DD" Date Observation date (UT)
13- 21 A9 -- Tel Telescope
25- 27 F3.1 0.1nm Res Spectral resolution
30- 31 I2 min ExpTime Exposure time
34- 35 I2 -- Nexp Number of exposures
39- 42 I4 0.1nm Lambdamin Spectral coverage, lower value
43 A1 --- --- [-]
44- 47 I4 0.1nm Lambdamax Spectral coverage, upper value
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Byte-by-byte Description of file: table[345].dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm Lambda Wavelength
8 A1 --- u_Lambda Uncertainty flag on Lambda
10- 14 F5.2 0.1nm Rest1 ? First rest wavelength
16- 19 F4.2 0.1nm Rest2 ? Second rest wavelength
21- 24 F4.2 0.1nm Rest3 ? Third rest wavelength
26- 29 F4.1 km/s HRV ?=- Heliocenttric radial velocity
30 A1 --- u_HRV Uncertainty flag on HRV
33- 39 F7.4 0.1nm EW ?=- Equivalent width
40 A1 --- u_EW Uncertainty flag on EW
43- 47 F5.1 km/s FWHM ?=- Line Full Width Half Maximum
(only in tables 3 and 5)
48 A1 --- u_FWHM Uncertainty flag on FWHM
51- 73 A23 --- Id Line identification
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Acknowledgements: Alexandre Oliveira, aoliveira(at)ctio.noao.edu
(End) Alexandre Oliveira [SOAR Telescope], Patricia Vannier [CDS] 20-Oct-2005