2012A&A...543A..18L


Query : 2012A&A...543A..18L

2012A&A...543A..18L - Astronomy and Astrophysics, volume 543A, 18-18 (2012/7-1)

O-star mass-loss rates at low metallicity.

LUCY L.B.

Abstract (from CDS):

Mass fluxes J are computed for the extragalactic O stars investigated by Tramper et al. (2011ApJ...741....8C, TSKK). For one early-type O star, computed and observed rates agree within errors. However, for two late-type O stars, theoretical mass-loss rates underpredict observed rates by ∼1.6dex, far exceeding observational errors. A likely cause of the discrepancy is overestimated observed rates due to the neglect of wind-clumping. A less likely but intriguing possibility is that, in observing O stars with Z/Z∼1/7, TSKK have serendipitously discovered an additional mass-loss mechanism not evident in the spectra of Galactic O stars because of their powerful radiation-driven winds. Constraints on this unknown mechanism are discussed. In establishing that the discrepancies, if real, are inescapable for purely radiation-driven winds, failed searches for high-J solutions are reported and the importance stressed of a numerical technique that cannot spuriously create or destroy momentum. The Z-dependences of the computed rates for Z/Z∈(1/30,2) show significant departures from a single power law, and these are attributed to curve-of-growth effects in the differentially expanding reversing layers. The best-fitting power-law exponents range from 0.68-0.97.

Abstract Copyright:

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

Simbad objects: 8

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Number of rows : 8
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     ~ 10536 1
2 [BUG2007] C 9 * 01 04 38.6516480040 +02 09 43.467624756     19.02   19.29 O8III((f)) 5 0
3 [BUG2007] B 11 s*b 01 04 43.8330093912 +02 06 45.160758216 17.51 18.55 18.68   18.84 O9.5 10 0
4 IC 1613 GiC 01 04 54.2 +02 08 00   10.42 10.01 9.77   ~ 1188 2
5 [BUG2007] A 11 s*b 01 05 03.4311881256 +02 09 45.727132212 17.54 18.09 18.08   18.01 B9Ia 7 0
6 [BUG2007] A 13 * 01 05 06.2582828976 +02 10 43.265668440     19.02   19.26 O3/4V((f)) 11 0
7 [BUG2007] A 15 * 01 05 08.7811622736 +02 09 59.570342388     19.35   19.59 O9.5III 7 0
8 NGC 3109 G 10 03 06.877 -26 09 34.46 11.10 10.42 10.04 9.91   ~ 742 2

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2023.02.02-19:42:25

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