J/AJ/121/413 Far-Infrared Emission of the ISM around HD193793 (Arnal+, 2001)
A high-resolution HI study of the interstellar medium local to HD193793.
Arnal E.M.
<Astron. J., 121, 413-425 (2001)>
=2001AJ....121..413A 2001AJ....121..413A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Wolf-Rayet ; H I data ; Interstellar medium
Keywords: ISM: Bubbles, Radio Emission Lines, Stars: Individual:
Henry Draper Number: HD193793, Stars: Wolf-Rayet
Abstract:
A 2 deg field centered at the optical position of the Wolf-Rayet (WR)
star HD193793 (= WR140) was surveyed in the HI 21cm line and in the
1420MHz radio continuum, using the Dominion Radio Astrophysical
Observatory interferometer. The aim of this observations was to look
for evidence of an interaction between the WR star and its local
interstellar medium (ISM). Our HI data displays a large oval minimum
at a velocity of Vsys~=-12km.s-1, close to the optical position of
HD193793. We believe this H I void was created by WR140 and its
massive companion (HD193793 is a member of a well-known binary
system). The major axis of the HI void is ∼11.5pc and its axial ratio,
the ratio of major to minor axis, is ∼1.4. This structure is
observable over a velocity range of around 11km.s-1. The HI minimum
appears surrounded by a clumpy shell of HI in emission that has a
total mass of neutral hydrogen of MHI∼1300 solar masses. The
kinematical distance corresponding to a local standard of rest
velocity of -12km.s-1 is approximately 5.4kpc, which disagrees with
the distance of HD193793, namely, around 1kpc. Therefore, it is
concluded that the HI bubble was blown in an ISM having non-negligible
peculiar motions. Hipparcos proper-motion measurements indicate that
HD193793 has a tangential velocity of 28±3 km.s-1 along the major
axis of one of the HI minima detected in the interior of the main HI
cavity. To reconcile this motion with the physical size of the HI
structure blown by the winds of the binary system, it is concluded
that such tangential velocity was acquired by the system a short while
ago, namely, ∼1.3 x 105yr. Maps from the IRAS database show a
large-scale IR feature, with good spatial correlation with the HI
shell surrounding the main HI void. We believe the emission from the
IR shell arises from dust grains heated by the energetic stellar
continuum photons emitted by the stellar objects.
Description:
Study of the infrared counterpart for the ISM local to HD193793. The
dust temperature is derived from the IRAS 60 and 100µm surface
brightnesses.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 46 6 Measured Infrared Fluxes
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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 A1 --- Region Region
3- 4 I2 h RAh Right ascension of centroid (J2000)
6- 7 I2 min RAm Right ascension of centroid (J2000)
9- 10 I2 s RAs Right ascension of centroid (J2000)
12 A1 --- DE- Sign of the declination centroid (J2000)
13- 14 I2 deg DEd Declination of centroid (J2000)
16- 17 I2 arcmin DEm Declination of centroid (J2000)
19- 20 I2 arcsec DEs Declination of centroid (J2000)
22- 27 E6.1 sr Angle Solid Angle
29- 32 I4 Jy S60 Estimated flux density at 60 µm
34- 37 I4 Jy S100 Estimated flux density at 100 µm
39- 42 F4.1 K Temp Mean dust temperature (1)
44- 46 F3.1 K e_Temp Uncertainty in Temp (2)
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Note (1): The temperature was derived by fitting to the data a modified Planck
function of the form νm * Bν(Temp), where the adopted value
for m is 2.
Note (2): The errors are derived on the assumption that the IR fluxes at 60
and 100 µm are accurate to 21% and 32%, respectively
(Fich & Terebey 1996).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Laurent Cambresy [CDS] 18-Aug-2004