J/MNRAS/493/1512 Galactic Wolf-Rayet stars with Gaia DR2 I (Rate+, 2020)
Unlocking Galactic Wolf-Rayet stars with Gaia DR2.
I. Distances and absolute magnitudes.
Rate G., Crowther P.A.
<Mon. Not. R. Astron. Soc., 493, 1512-1529 (2020)>
=2020MNRAS.493.1512R 2020MNRAS.493.1512R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Wolf-Rayet ; Stars, double and multiple ;
Stars, distances ; Spectral types ; Parallaxes, trigonometric ;
Extinction ; Milky Way ; Optical ; Infrared
Keywords: stars: distances - stars: massive - stars: Wolf-Rayet - Galaxy: disc
Abstract:
We obtain distances to 383 Galactic Wolf-Rayet (WR) stars from Gaia
DR2 parallaxes and Bayesian methods, with a prior based on HII regions
and dust extinction. Distances agree with those from Bailer-Jones et
al. for stars up to 2kpc from the Sun, though deviate thereafter due
to differing priors, leading to modest reductions in luminosities for
recent WR spectroscopic results. We calculate visual and K-band
absolute magnitudes, accounting for dust extinction contributions and
binarity, and identify 187 stars with reliable absolute magnitudes.
For WR and O stars within 2kpc, we find a WR/O ratio of 0.09. The
distances are used to generate absolute magnitude calibrations and
obtain the Gaia colour-magnitude diagram for WR stars. Average
vWR-band absolute magnitudes for WN stars range from -3.6 mag (WN3-4)
to -7.0mag (WN8-9ha), and -3.1(WO2-4) to -4.6mag (WC9), with standard
deviations of ∼0.6mag. Using HII region scale heights, we identify 31
WR stars at large (3σ, |z|≥156pc) distances from the mid-plane
as potential runaways accounting for the Galactic warp, of which only
four involve WN8-9 stars, contrary to previous claims.
Description:
The second Gaia data release (Gaia Collaboration, 2018A&A...616A...1G 2018A&A...616A...1G,
Cat. I/345) offers parallaxes, proper motions, and positions for over
a billion stars in the Galaxy. A large fraction of the Galactic WR
population have been detected in the Gaia G band, (330-1050nm) and so
Gaia increases the number of WR with trigonometric parallaxes from
just one (WR11 in Hipparcos, van Leeuwen 2007A&A...474..653V 2007A&A...474..653V, Cat.
I/311) to almost 400.
In this work, we present distances obtained using Gaia data and
discuss the resulting new insights into WR absolute magnitudes,
runaways and physical parameters. We determine the most likely
distances for Galactic WR stars using a Bayesian method and validate
these using absolute magnitudes. Distances from the Galactic mid-plane
are discussed and used to identify potential runaways.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 150 380 GaiaDR2 astrometric, photometric, and parallax
properties for 383 Galactic WR stars
table2.dat 69 13 Intrinsic colours of WR stars from PoWR models
and Rosslowe & Crowther (2015MNRAS.447.2322R 2015MNRAS.447.2322R)
table3.dat 22 10 The relative continuum flux contribution of WR
stars to O-type companions at near-IR
wavelengths for various subtypes
table4.dat 35 10 Conversion equations between narrowband v and
Gaia G-band filters for (GBP-GRP)0 of
different spectral types, using results from
Carrasco & Jordi (valid for Av<12)
table5.dat 31 15 Average absolute magnitudes for Galactic WR
subtypes in v and Ks band filters
table6.dat 103 375 Absolute Ks-band magnitudes for Galactic WR
stars
table7.dat 97 375 Absolute v-band magnitudes for Galactic WR stars
table8.dat 90 25 WR stars within 2kpc of the Sun, including
colour excess, K-band extinction, and AKs/kpc,
extinction per kpc
table9.dat 59 31 Distance of WR stars from the mid-plane |z|, for
which excesses exceed 3σ, where
σ=52pc is the HII region scale height
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- WR WR star name (WRNNN, WRNNNa, WRNNNaa or
WRNNN-NN)
10 A1 --- f_WR [*] Flag on WR (1)
12- 31 A20 --- SpType Spectral type
33- 57 A25 --- Name Alternative name
59- 60 I2 h RAh Right ascension (ICRS) at Ep=2015.5
62- 63 I2 min RAm Right ascension (ICRS) at Ep=2015.5
65- 69 F5.2 s RAs Right ascension (ICRS) at Ep=2015.5
71 A1 --- DE- Declination sign (ICRS) at Ep=2015.5
72- 73 I2 deg DEd Declination (ICRS) at Ep=2015.5
75- 76 I2 arcmin DEm Declination (ICRS) at Ep=2015.5
78- 81 F4.1 arcsec DEs Declination (ICRS) at Ep=2015.5
83- 89 F7.3 mas plx Zero-point corrected Gaia DR2 parallax
91- 95 F5.3 mas e_plx Error on plx
97-101 F5.2 kpc Dist Distance from the sun
103-106 F4.2 kpc E_Dist Upper error on Dist
108-111 F4.2 kpc e_Dist Lower error on Dist
113-116 I4 pc z Distance from the mid-plane
118-120 I3 pc E_z Upper error on z
122-124 I3 pc e_z Lower error on z
126-130 F5.2 mag Gmag Gaia DR2 G-band magnitude
132-136 F5.2 mag BP-RP ? Gaia DR2 BP-RP colour index
138-141 F4.2 --- Excess ? Astrometric excess noise
143-146 F4.2 [Lsun] logL ? Logarithm of the stellar luminosity (2)
148-150 A3 --- flag [aeng ] Error flag (3)
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Note (1): Flag as follows:
* = For WR11 we used parallax and photometry from Hipparcos (van Leeuwen
2007A&A...474..653V 2007A&A...474..653V, Cat. I/311). The distance was calculated in the
same manner as WR with Gaia results, except the adjustments to calculate
ϖ and σϖ were not applied.
Note (2): Stellar luminosities, updated from Hamann et al. (2019A&A...625A..57H 2019A&A...625A..57H)
and Sander et al. (2019A&A...621A..92S 2019A&A...621A..92S) according to our revised
distances, are restricted to sources with no error flags
Note (3): Flag as follows:
a = astrometric excess noise >1mas
e = large parallax uncertainty |σ_ϖ/ϖ|>1
n = negative parallax ϖ<0
g = good astrometry
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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- 7 A7 --- Subtype Wolf-Rayet subtype
9- 17 A9 --- Model PoWR model (1)
19- 22 F4.2 --- logT/k ? Logarithm of T/k
24- 26 F3.1 --- logRt ? Logarithm of Rt
28- 32 F5.2 mag b-v b-v colour index from PoWR grids
34- 36 F3.1 mag e_b-v Error on b-v
38- 43 F6.3 mag J-Ks J-Ks colour index from PoWR grids
45- 47 F3.1 mag e_J-Ks Error on J-Ks
49- 53 F5.2 mag H-Ks H-Ks colour index from PoWR grids
55- 57 F3.1 mag e_H-Ks Error on H-Ks
59- 63 F5.2 mag J-K ? Intrinsic J-K colour index taken from
Rosslowe & Crowther (2015MNRAS.447.2322R 2015MNRAS.447.2322R)
65- 69 F5.2 mag H-K ? Intrinsic H-K colour index taken from
Rosslowe & Crowther (2015MNRAS.447.2322R 2015MNRAS.447.2322R)
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Note (1): We used Hamann & Grafener (2004A&A...427..697H 2004A&A...427..697H) and Todt et al.
(2015A&A...579A..75T 2015A&A...579A..75T) for WN; Sander et al. (2012A&A...540A.144S 2012A&A...540A.144S) for
WC.
For WN/WC stars, the value (b-v)=-0.23 is averaged from the E(b-v)
values of Sander et al. (2012A&A...540A.144S 2012A&A...540A.144S) and the b and v
apparent magnitudes of each star.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Subtype Wolf-Rayet subtype
7 I1 --- VWR/VO Relative V-band continuum flux contribution
of the WR star to O-type companion (1)
9- 12 F4.2 --- JWR/JO Relative J-band continuum flux contribution
of the WR star to O-type companion (1)
14- 17 F4.2 --- HWR/HO Relative H-band continuum flux contribution
of the WR star to O-type companion (1)
19- 22 F4.2 --- KWR/KO Relative K-band continuum flux contribution
of the WR star to O-type companion (1)
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Note (1): Relative fluxes obtained adopting a Kurucz ATLAS O star model with
Teff=37500K and logg=5 for the companion, assuming each contribute
50% of the V-band continuum flux.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Subtype Wolf-Rayet subtype
9- 14 F6.3 --- BP-RP Gaia DR2 BP-RP colour index
16- 35 A20 --- Conv Conversion equation between Av and AG
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Subtype Wolf-Rayet subtype
9- 12 F4.1 mag vMAG ? Average absolute Smith v-band magnitude (1)
14- 16 F3.1 mag e_vMAG ? Error on vMAG
18- 19 I2 --- Nv ? Number of stars considered to obtain vMAG
21- 24 F4.1 mag KsMAG Average absolute Ks-band magnitude
26- 28 F3.1 mag e_KsMAG Error on KsMAG
30- 31 I2 --- NKs Number of stars considered to obtain KsMAG
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Note (1): In the v-band, the WC9d sample has been combined with non dusty
WC9 stars
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- WR WR star name (WRNNN, WRNNNa, WRNNNaa or
WRNNN-NN)
10- 29 A20 --- SpType Spectral type
31- 35 F5.2 mag Ksmag ? Ks-band apparent magnitude
37- 41 F5.2 mag mu Distance modulus
43- 46 F4.2 mag J-Ks ? J-Ks colour index
48- 51 F4.2 mag H-Ks ? H-Ks colour index
53- 57 F5.2 mag AKs ? Ks-band extinction
59- 62 F4.2 mag e_AKs ? Error on AKs
64- 68 F5.1 mag KsMAGS ? Absolute Ks magnitude of binary system
70- 72 F3.1 mag E_KsMAGS ? Upper error on KsMAGS
74- 76 F3.1 mag e_KsMAGS ? Lower error on KsMAGS
78- 81 F4.2 --- KsWR/KsS ? Fraction of light contributed to the
binary system by the WR component
83- 86 F4.2 --- e_KsWR/KsS ? Error on KsWR/KsS
88- 92 F5.1 mag KsMAGWR ? Absolute Ks-band magnitude of WR star
94- 96 F3.1 mag E_KsMAGWR ? Upper error on KsMAGWR
98-100 F3.1 mag e_KsMAGWR ? Lower error on KsMAGWR
102-103 A2 --- flag Error flag (G1)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- WR WR star name (WRNNN, WRNNNa, WRNNNaa or
WRNNN-NN)
10- 29 A20 --- SpType Spectral type
31- 35 F5.2 mag vmag ? Smith v-band apparent magnitude
37- 41 F5.2 mag mu Distance modulus
43- 47 F5.2 mag b-v ? b-v colour index
49- 53 F5.2 mag Av ? Smith v-band extinction
55- 58 F4.2 mag e_Av ? Error on Av
60- 63 F4.1 mag vMAGS ? Absolute Smith v-band magnitude of binary
system
65- 67 F3.1 mag E_vMAGS ? Upper error on vMAGS
69- 71 F3.1 mag e_vMAGS ? Lower error on vMAGS
73- 76 F4.2 --- vWR/vS ? Fraction of light contributed to the
binary system by the WR component
78- 81 F4.2 --- e_vWR/vS ? Error on vWR/vS
83- 86 F4.1 mag vMAGWR ? Absolute Smith v-band magnitude of WR star
88- 90 F3.1 mag E_vMAGWR ? Upper error on vMAGWR
92- 94 F3.1 mag e_vMAGWR ? Lower error on vMAGWR
96- 97 A2 --- flag Error flag (G1)
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- WR WR star name (WRNNN, WRNNNa or WRNNN-NN)
9- 24 A16 --- Name Alternative name
26- 38 A13 --- SpType Spectral type
40- 43 F4.2 kpc Dist Distance
45- 48 F4.2 kpc E_Dist Upper error on Dist
50- 53 F4.2 kpc e_Dist Lower error on Dist
55 A1 --- flag Error flag (G1)
57- 60 F4.2 mag E(B-V) ? Colour excess
62- 65 F4.2 mag e_E(B-V) ? Error on E(B-V)
67- 70 F4.2 mag AKs Ks-band extinction
72- 75 F4.2 mag e_AKs Error on AKs
77- 80 F4.2 mag/kpc AKs/kpc Extinction per kpc
82- 85 F4.2 mag/kpc E_AKs/kpc Upper error on AKs/kpc
87- 90 F4.2 mag/kpc e_AKs/kpc Lower error on AKs/kpc
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- WR WR star name (WRNNN)
7- 14 A8 --- SpType Spectral type
16- 19 F4.2 kpc Dist Distance
21- 24 F4.2 kpc E_Dist Upper error on Dist
26- 29 F4.2 kpc e_Dist Lower error on Dist
31- 34 I4 pc z Distance from the mid-plane in pc
36- 38 I3 pc E_z Upper error on z
40- 42 I3 pc e_z Lower error on z
44- 47 F4.1 --- zHIIsig Distance from the mid-plane in σ,
where σ=52pc is the HII region scale
height
49- 51 F3.1 --- E_zHIIsig Upper error on zHIIsig
53- 55 F3.1 --- e_zHIIsig Lower error on zHIIsig
57- 59 A3 --- Runaway [Yes/No ] Indicates if the star is a known
runaway according to Rosslowe & Crowther
(2015MNRAS.447.2322R 2015MNRAS.447.2322R)
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Global Notes:
Note (G1): Flag as follows:
b = M>upperinitial or M<lowerinitial
b: = M>upperfinal or M<lowerfinal
g = Results with no issues
u = Results without any absolute magnitudes
Where upper and lower are the upper and lower magnitude bounds of the absolute
magnitude average; initial denotes the averages calculated before sigma
clipping, final are the final absolute magnitude boundaries and M is the
absolute magnitude of individual WR stars
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History:
From electronic version of the journal
References:
Rate et al., Paper II 2020MNRAS.495.1209R 2020MNRAS.495.1209R
(End) Ana Fiallos [CDS] 12-Apr-2023