2011A&A...535A..32N


Query : 2011A&A...535A..32N

2011A&A...535A..32N - Astronomy and Astrophysics, volume 535A, 32-32 (2011/11-1)

L-band spectroscopy of galactic OB-stars.

NAJARRO F., HANSON M.M. and PULS J.

Abstract (from CDS):

Mass-loss, occurring through radiation driven supersonic winds, is a key issue throughout the evolution of massive stars. Two outstanding problems are currently challenging the theory of radiation-driven winds: wind clumping and the weak-wind problem. We seek to obtain accurate mass-loss rates of OB stars at different evolutionary stages to constrain the impact of both problems in our current understanding of massive star winds. We perform a multi-wavelength quantitative analysis of a sample of ten Galactic OB-stars by means of the atmospheric code cmfgen, with special emphasis on the L-band window. A detailed investigation is carried out on the potential of Brα and Pfγ as mass-loss and clumping diagnostics. For objects with dense winds, Brα samples the intermediate wind while Pfγ maps the inner one. In combination with other indicators (UV, Hα, Brγ) these lines enable us to constrain the wind clumping structure and to obtain ``true'' mass-loss rates. For objects with weak winds, Brα emerges as a reliable diagnostic tool to constrain {dot}(M). The emission component at the line Doppler-core superimposed on the rather shallow Stark absorption wings reacts very sensitively to mass loss already at very low {dot}(M) values. On the other hand, the line wings display similar sensitivity to mass loss as Hα, the classical optical mass loss diagnostics. Our investigation reveals the great diagnostic potential of L-band spectroscopy to derive clumping properties and mass-loss rates of hot star winds. We are confident that Brα will become the primary diagnostic tool to measure very low mass-loss rates with unprecedented accuracy.

Abstract Copyright:

Journal keyword(s): infrared: stars - stars: early-type - stars: winds, outflows - stars: mass-loss

Simbad objects: 22

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Number of rows : 22
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 10689 1
2 HD 7113 Em* 01 09 12.94464 -73 11 38.8968     11.7     ~ 120 0
3 * alf Cam s*b 04 54 03.0103983 +66 20 33.636467 3.47 4.34 4.29 4.18 4.18 O9Ia 655 1
4 HD 33654 * 05 14 44.2726788240 +53 12 50.208440220 6.280 6.240 6.160     A0V 49 0
5 * lam Ori A Em* 05 35 08.2760807112 +09 56 02.991326316 2.17 3.48 3.47     O8III((f)) 503 0
6 Cl Collinder 69 OpC 05 35 10.1 +09 48 47     2.8     ~ 299 0
7 * eps Ori s*b 05 36 12.81335 -01 12 06.9089 0.48 1.51 1.69 1.76 1.93 B0Ia 890 0
8 * sig Ori Y*O 05 38 44.7653828520 -02 36 00.283179888 2.54 3.58 3.79 3.87 4.11 O9.5V+B0.2V(n) 786 0
9 * zet Pup BY* 08 03 35.04754 -40 00 11.3321 0.89 1.98 2.25 2.36 2.58 O4I(n)fp 1144 1
10 HD 76341 Em* 08 54 00.6139723224 -42 29 08.763425340 6.88 7.392 7.163 8.08   O9.2IV 104 1
11 HD 93129A SB* 10 43 57.4587319296 -59 32 51.394897284 6.46 7.478 7.310 7.84   O2If* 162 0
12 * tau Sco * 16 35 52.9528530 -28 12 57.661515 1.55 2.56 2.81 2.93 3.18 B0.2V 907 0
13 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 712 0
14 * alf Lyr dS* 18 36 56.33635 +38 47 01.2802 0.03 0.03 0.03 0.07 0.10 A0Va 2640 0
15 Ass Cyg OB 2 As* 20 33.2 +41 19           ~ 900 0
16 Schulte 7 * 20 33 14.1095938872 +41 20 21.904113804 12.24 12.00 10.55     O3If* 141 0
17 BD+40 4227A SB* 20 33 15.0781182864 +41 18 50.479292556 10.42 10.27 8.98 8.03 6.83 O6Ib(fc)+O4.5:III:(fc) 242 0
18 Schulte 8C * 20 33 17.9820761856 +41 18 31.194812988 12.2 11.43 10.19     O4.5III(fc) 82 0
19 * lam Cep s*b 22 11 30.5765111040 +59 24 52.154264880 4.55 5.29 5.05 4.77 4.62 O6.5I(n)fp 678 1
20 * 10 Lac ** 22 39 15.6786372 +39 03 00.971152 3.650 4.670 4.880 4.98 5.19 O9V 748 0
21 HD 217086 Y*O 22 56 47.1887590800 +62 43 37.657173900 7.88 8.30 7.66 8.35   O7Vnn((f))z 254 0
22 HD 219190 PM* 23 14 07.8749617272 -08 23 14.125487928   9.19 8.47     G3IV 22 0

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2023.06.08-08:04:21

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