J/A+A/547/A83 Rotating Wolf-Rayet stars in post RSG/LBV phase (Graefener+, 2012)
Rotating Wolf-Rayet stars in a post RSG/LBV phase. An evolutionary channel
towards long-duration GRBs?
Graefener G., Vink J.S., Harries T.J., Langer N.
<Astron. Astrophys., 547, A83-83 (2012)>
=2012A&A...547A..83G 2012A&A...547A..83G
ADC_Keywords: Stars, Wolf-Rayet ; Polarization
Keywords: stars: Wolf-Rayet - stars: rotation - stars: winds, outflows -
stars: evolution - Gamma-ray burst: general - polarization
Abstract:
Wolf-Rayet (WR) stars with fast rotating cores are thought to be the
direct progenitors of long-duration gamma-ray bursts (LGRBs). A well
accepted evolutionary channel towards LGRBs is chemically-homogeneous
evolution at low metallicities, which completely avoids a red
supergiant (RSG), or luminous blue variable (LBV) phase. On the other
hand, strong absorption features with velocities of several hundred
km/s have been found in some LGRB afterglow spectra (GRB 020813
and GRB 021004), which have been attributed to dense circumstellar
(CS) material that has been ejected in a previous RSG or LBV phase,
and is interacting with a fast WR-type stellar wind.
Here we investigate the properties of Galactic WR stars and their
environment to identify similar evolutionary channels that may lead to
the formation of LGRBs.
We compile available information on the spectropolarimetric properties
of 29 WR stars, the presence of CS ejecta for 172 WR stars, and
the CS velocities in the environment of 34 WR stars in the Galaxy.
We use linear line-depolarization as an indicator of rotation, nebular
morphology as an indicator of stellar ejecta, and velocity patterns in
UV absorption features as an indicator of increased velocities in the
CS environment.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 79 38 WR stars with IUE high-resolution data:
circumstellar, and spectropolarimetric properties
table5.dat 24 172 Ring nebulae around 172 Galactic WR stars, from
the Surveys by Marston (1997ApJ...475..188M 1997ApJ...475..188M),
and Miller & Chu (1993ApJS...85..137M 1993ApJS...85..137M)
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See also:
III/215 : 7th Catalog of Galactic Wolf-Rayet stars (van der Hucht, 2001)
VI/110 : Final Merged Log of IUE Observations (NASA-ESA, 2000)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- WR WR number (NNNaa) (G2)
7- 12 I6 --- HD HD number
13 A1 --- m_HD [B] Multiplicity index on HD
15- 22 A8 --- IUE IUE name, SWPNNNNN
24- 40 A17 --- SpType Spectral type from van der Hucht (2001,
Cat. III/215)
42 A1 --- LE [+*-] line effect according to
Harries et al. (1998MNRAS.296.1072H 1998MNRAS.296.1072H) (1)
44- 49 A6 --- RN Detections of ring nebulae (G1)
51- 54 A4 --- NF Detections of circumstellar displacements according
to Nichols & Fesen (1994A&A...291..283N 1994A&A...291..283N) (2)
56 A1 --- l_FWHM1 Limit flag on FWHM1
57- 61 F5.1 km/s FWHM1 ?=- CIV 1548 circumstellar broadening velocities
63- 67 F5.1 km/s FWHM2 ?=- CIV 1550 circumstellar broadening velocities
69- 79 A11 --- Class Tentative classification of the morphology of
the observed CIV absorption features (cf. Fig. 1)
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Note (1): the "line effect" or spectropolarimetric line de-polarization
is an indicator of enhanced surface rotation rates. Codes as follows:
+ = line effect
* = line effect due to binarity
- = non-detection
Note (2): NF codes as follows:
NF++ = safe detection
NF+ = detection with possible super-shell
NF- = non-detection
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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- 5 A5 --- WR WR name (G2)
7- 10 A4 --- Ma97 Nebular classifications by Marston
(1997ApJ...475..188M 1997ApJ...475..188M) (G1)
12- 15 A4 --- MC93 Nebular classifications by Miller & Chu
(1993ApJS...85..137M 1993ApJS...85..137M) (G1)
17- 19 A3 --- Ch91 Nebular classifications by Chu
(1991, IAU Symp., 143, 349) (G1)
21- 24 A4 ---- SB10 Nebular classifications by Stock & Barlow
(2010MNRAS.409.1429S 2010MNRAS.409.1429S) (G1)
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Global Notes:
Note (G1): the ring nebulae are characterized by:
R = radiatively excited HII regions (Chiu 1981ApJ...249..195C 1981ApJ...249..195C)
W = wind-blown bubbles (Chiu 1981ApJ...249..195C 1981ApJ...249..195C)
E = stellar ejecta (Chiu 1981ApJ...249..195C 1981ApJ...249..195C)
RN = ring nebula (Miller and Chiu 1993ApJS...85..137M 1993ApJS...85..137M)
RN? = probable ring nebula (Miller and Chiu 1993ApJS...85..137M 1993ApJS...85..137M)
RN?? = possible ring nebula (Miller and Chiu 1993ApJS...85..137M 1993ApJS...85..137M)
- = no ring nebula
Note (G2): Some stellar designations have been updated with respect to the
original works:
* WR 31a --> WR 31c;
* WR 43 is a cluster of WR stars without ring nebula (NGC 3603)
--> WR 42a, WR 42b, WR 42c;
* WR153 --> WR 153ab.
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Jan-2013