J/MNRAS/470/3765 Mass-loss rates in LMC and SMC O stars (Massa+, 2017)
Mass-loss rates from mid-infrared excesses in LMC and SMC O stars.
Massa D., Fullerton A.W., Prinja R.K.
<Mon. Not. R. Astron. Soc., 470, 3765-3774 (2017)>
=2017MNRAS.470.3765M 2017MNRAS.470.3765M (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, O ; Photometry, UBV ;
Effective temperatures
Keywords: stars: early-type - stars: winds, outflows - Magellanic Clouds
Abstract:
We use a combination of BVJHK and Spitzer [3.6], [5.8] and [8.0]
photometry to determine infrared (IR) excesses for a sample of 58
Large Magellanic Cloud and 46 Small Magellanic Cloud O stars. This
sample is ideal for determining IR excesses because the very small
line-of-sight reddening minimizes uncertainties due to extinction
corrections. We use the core-halo model developed by Lamers & Waters
to translate the excesses into mass-loss rates and demonstrate that
the results of this simple model agree with the more sophisticated
CMFGEN models to within a factor of 2. Taken at face value, the
derived mass-loss rates are larger than those predicted by Vink et al.
(2001A&A...369..574V 2001A&A...369..574V), and the magnitude of the disagreement increases
with decreasing luminosity. However, the IR excesses need not imply
large mass-loss rates. Instead, we argue that they probably indicate
that the outer atmospheres of O stars contain complex structures and
that their winds are launched with much smaller velocity gradients
than normally assumed. If this is the case, it could affect the
theoretical and observational interpretations of the 'weak wind'
problem, where classical mass-loss indicators suggest that the
mass-loss rates of lower luminosity O stars are far less than
expected.
Description:
We concentrate on a sub-sample of the Bonanos et al. (2009, Cat.
J/AJ/138/1003; 2010, Cat. J/AJ/140/416) catalogues, namely those O
stars which are also in the Blair et al. (2009, Cat. J/PASP/121/634)
FUSE sample.
Our sample contained 46 SMC and 58 LMC O stars (see Tables 1 and 2)
The results of the fits are presented in Tables 3 and 4.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 46 SMC stellar properties
table2.dat 83 58 LMC Stellar Properties
table3.dat 74 46 SMC wind properties
table4.dat 70 58 LMC wind properties
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See also:
J/PASP/121/634 : FUSE observations in Magellanic Clouds (Blair+, 2009)
J/AJ/138/1003 : IR photometry of massive LMC stars (Bonanos+, 2009)
J/AJ/140/416 : IR photometry of massive stars in the SMC (Bonanos+, 2010)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star name
14- 27 A14 --- SpType Spectral Type
29- 31 A3 --- r_SpType Source for spectral type (1)
36- 40 F5.2 mag Vmag V band magnitude
45- 49 F5.2 mag B-V (B-V) colour index
54- 58 I5 K Teff Effective temperature
63- 66 F4.2 [Lsun] logL Log of luminosity
71- 75 F5.2 Msun Mass Stellar mass
79- 83 F5.2 Rsun Radius Stellar radius
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Note (1): References for spectral types:
B09 = Bonanos et al. (2009AJ....138.1003B 2009AJ....138.1003B, Cat. J/AJ/138/1003)
B10 = Bonanos et al. (2010AJ....140..416B 2010AJ....140..416B, Cat. J/AJ/140/416)
M95 = Massey et al. (1995ApJ...438..188M 1995ApJ...438..188M)
M02 = Massey et al. (2002ApJS..141...81M 2002ApJS..141...81M, Cat. II/236)
M09 = Massey et al. (2009ApJ...692..618M 2009ApJ...692..618M)
P09 = Penny & Gies (2009ApJ...700..844P 2009ApJ...700..844P, Cat. J/ApJ/700/844)
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star name
13- 16 I4 km/s Vinf Wind terminal velocity
19- 21 A3 --- r_Vinf Reference for terminal velocity (1)
25- 28 F4.2 Msun/yr dM/dtTh Theoretical mass loss rate (2)
31- 35 F5.2 Msun/yr dM/dtIR Mass loss rate determined from SED fit
38- 42 F5.2 Msun/yr e_dM/dt The 1(sigma) error in Mdot_IR
46- 49 F4.2 mag E(B-V) Reddening determined from SED fit
52- 56 F5.3 mag e_E(B-V) The 1σ uncertainty in E(B-V)
60- 63 F4.2 mag E(B-V)0 Reddening determined from Spectral type
66- 70 F5.2 --- chi2 Reduced chi squared of SED fit
74 A1 --- Notes Notes on IR SED (3)
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Note (1): References for terminal velocities:
C16 = Crowther et al. (2016MNRAS.458..624C 2016MNRAS.458..624C)
E04 = Evans et al. (2004ApJ...607..451E 2004ApJ...607..451E)
M04 = Massey et al. (2004ApJ...608.1001M 2004ApJ...608.1001M)
M05 = Massey et al. (2005ApJ...627..477M 2005ApJ...627..477M)
M09 = Massey et al. (2009ApJ...692..618M 2009ApJ...692..618M)
M07 = Mokiem et al. (2007A&A...473..603M 2007A&A...473..603M)
P96 = Puls et al. (1996A&A...305..171P 1996A&A...305..171P)
VVV = Terminal velocity determined using Vink et al. (2001A&A...369..574V 2001A&A...369..574V)
formulae
Note (2): Mass loss determined using Vink et al. (2001A&A...369..574V 2001A&A...369..574V) formulae
Note (3): Notes as follows:
* = SED fit consistent with no wind emission
D = Probable disk
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Apr-2020