J/A+A/674/A88 Northern late-type nitrogen-rich WR (WNL) spectra (Dsilva+, 2023)
A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars.
III. The northern late-type nitrogen-rich sample.
Dsilva K., Shenar T., Sana H., Marchant P.
<Astron. Astrophys. 674, A88 (2023)>
=2023A&A...674A..88D 2023A&A...674A..88D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Spectra, optical
Keywords: stars: Wolf-Rayet - techniques: radial velocities -
methods: statistical - binaries: spectroscopic
Abstract:
Massive stars are powerful cosmic engines. In the phases immediately
preceding core-collapse, massive stars in the Galaxy with Mi>20M☉
may appear as classical Wolf-Rayet (WR) stars.
As the final contribution of a homogeneous RV survey, this work
constrains the multiplicity properties of northern Galactic late-type
nitrogen-rich Wolf-Rayet (WNL) stars. We compare their intrinsic
binary fraction and orbital period distribution to the carbon-rich
(WC) and early-type nitrogen-rich (WNE) populations from previous
works.
We obtained high-resolution spectra of the complete magnitude-limited
sample of 11 Galactic WNL stars with the Mercator telescope on the
island of La Palma. We used cross-correlation to measure relative RVs
and flagged binary candidates based on the peak-to-peak RV dispersion.
By using Monte Carlo sampling and a Bayesian framework, we computed
the three-dimensional likelihood and one-dimensional posteriors for
the upper period cut-off (logPmaxWNL), power-law index ({PI}WNL),
and intrinsic binary fraction (fintWNL).
Adopting a threshold C of 50km/s, we derived fobsWNL=0.36±0.15.
Our Bayesian analysis produces fintWNL=0.42-0.17+0.15,
{PI}WNL=-0.70-1.02+0.73 and logPmaxWNL=4.90-3.40+0.09
for the parent WNL population. The combined analysis of the Galactic
WN population results in fintWN=0.52-0.12+0.14,
{PI}WN=-0.99-0.50+0.57 and logPmaxWN=4.99+1.11+0.00.
The observed period distribution of Galactic WN and WC
binaries from the literature is in agreement with what is found.
The period distribution of Galactic WN binaries peaks at P∼1-10d and
that of the WC population at P∼5000d. This shift cannot be reconciled
by orbital evolution due to mass loss or mass transfer. At long
periods, the evolutionary sequence O (->LBV) -> WN -> WC seems
feasible. The high frequency of short-period WN binaries compared to
WC binaries suggests that they either tend to merge or that the WN
components in these binaries rarely evolve into WC stars in the
Galaxy.
Description:
The spectra used in this analyses are provided here.
Over the course of the RV monitoring campaign, we obtained at least
six epochs with the 1.2m Mercator telescope on La Palma using the
HERMES spectrograph. HERMES covers the optical regime with a
wavelength range from 3800Å to 9000Å with a resolving power
of R=λ/{DELTA}λ∼85000. We also used archival HERMES data
in our analysis when available, resulting in a time baseline of two to
eight years. The number of spectra and time coverage for the 11 WNL
stars in our sample is shown in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 41 11 Eleven WNL stars in our RV monitoring campaign
list.dat 86 275 List of fits spectra
fits/* . 275 Individual fits spectra
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See also:
J/A+A/664/A93 : Northern WNE star spectra (Dsilva+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Star Star name
7- 8 I2 h RAh Simbad right ascension (J2000)
10- 11 I2 min RAm Simbad right ascension (J2000)
13- 17 F5.2 s RAs Simbad right ascension (J2000)
19 A1 --- DE- Simbad declination sign (J2000)
20- 21 I2 deg DEd Simbad declination (J2000)
23- 24 I2 arcmin DEm Simbad declination (J2000)
26- 29 F4.1 arcsec DEs Simbad declination (J2000)
31- 32 I2 --- Nsp Number of spectra
34- 37 I4 d Time Time baseline of coverage
39- 41 I3 --- S/N Average S/N per resolution element at 5100Å
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Star Star name
7- 12 I6 --- Nx Number of pixels along X-axis
14- 39 A26 "datime" Obs.date Observation date
41- 47 F7.5 [0.1nm] loglambda Wavelength
49- 52 I4 Kibyte size Size of FITS file
54- 72 A19 --- FileName Name of FITS file, in subdirectory fits
73- 86 A14 --- Title Title of the FITS file
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Acknowledgements:
Karah Dsilva, karan.singh.dsilva(at)ulb.be
References:
Dsilva et al., Paper I 2020A&A...641A..26D 2020A&A...641A..26D
Dsilva et al., Paper II 2022A&A...664A..93D 2022A&A...664A..93D, Cat. J/A+A/664/A93
(End) Patricia Vannier [CDS] 24-May-2023