J/A+A/435/575 86GHz SiO maser survey of late-type stars. III (Messineo+, 2005)
86 GHz SiO maser survey of late-type stars in the Inner Galaxy.
III. Interstellar extinction and colours of the SiO targets
Messineo M., Habing H.J., Menten K.M., Omont A., Sjouwerman L.O.,
Bertoldi F.
<Astron. Astrophys. 435, 575 (2005)>
=2005A&A...435..575M 2005A&A...435..575M
ADC_Keywords: Stars, late-type ; Infrared sources ; Masers ; Extinction
Keywords: stars: dust, extinction - stars: AGB and post-AGB - stars: mass-loss -
infrared: stars - circumstellar matter - Galaxy: stellar content
Abstract:
We have determined extinction corrections for a sample of 441
late-type stars in the inner Galaxy, which we previously searched for
SiO maser emission, using the 2MASS near-infrared photometry of the
surrounding stars. From this, the near-infrared extinction law is
found to be approximated by a power law
Alambda∝lambda-1.9±0.1. Near- and mid-infrared
colour-colour properties of known Mira stars are reviewed. From the
distribution of the dereddened infrared colours of the SiO target
stars we infer mass-loss rates between 10-7 and 10-5M☉/yr.
Description:
A catalogue of interstellar extinction estimates is presented for a
sample of 441 stars which we previously searched for SiO maser
emission (Messineo et al. 2002, Cat. J/A+A/393/115,
2004, Cat. J/A+A/418/103). The identification source numbers
(e.g #99) are taken from Table 2 (86 GHz SiO maser detections) and
Table 3 (non-detections) in Messineo et al. (2002, J/A+A/393/115),
and are the same as those used in Table 2 by Messineo et al. (2004,
J/A+A/418/103).
We estimated a mean extinction Aks in the direction of each SiO star
by using 2MASS stars within 2-4 arcmin of each SiO star. We therefore
shifted the colours of field stars (J-Ks) and (H-Ks) versus Ks
magnitudes along the reddening vector onto the reference RGB. For
fields with Aks<1.6mag table3 lists the extinction values determined
from the (Ks,J-Ks) plane, at larger extinction values those from the
(Ks,H-Ks) plane. For 46 "foreground" SiO targets Aks is an extinction
estimate obtained by directly shifting the colours of the SiO target
on the (H,Ks)-[15] colour-colour sequence.
The total (circumstellar plus interstellar) extinction of each SiO
target is measured by assuming a stellar photospheric (J-Ks)0 colour
of 1.4mag and an (H-Ks)0 colour of 0.5mag.
A group of 46 mostly very bright target stars (Ks<6.0), marked with
flag Fg=1, have total extinctions lower (a least 1 sigma) than the
"field" extinction and are therefore likely to be foreground objects.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 23 444 Interstellar extinction estimates Ak in the
direction of SiO targets
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See also:
J/A+A/393/115 : 86GHz SiO maser survey of late-type stars (Messineo+, 2002)
J/A+A/418/103 : 86GHz SiO maser survey in the Inner Galaxy (Messineo+, 2004)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [MHS2002] Identification number (1)
5- 9 F5.2 mag Aks Interstellar extinction in Ks-band
11- 15 F5.2 mag s-Aks Dispersion of individual extinctions of
field stars
17- 21 F5.2 mag Tot ? Total (circumstellar plus interstellar)
extinction
23 I1 --- Fg [1]? Flag for foreground objects(2)
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Note (1): The number of targeted positions searched for SiO maser
emission in Messineo et al. (2002, Cat. J/A+A/393/115) is 441.
As three positions showed a double 86GHz SiO maser detection, the
line identification number goes up to 444.
Note (2): The flag Fg is unity when the SiO target is classified
as a foreground object.
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Acknowledgements: Maria Messineo, messineo(at)eso.org
(End) Patricia Vannier [CDS] 21-Feb-2005