J/A+A/546/A16 22-GHz water maser clouds (Richards+, 2012)
Evolved star water maser cloud size determined by star size.
Richards A.M.S., Etoka S., Gray M.D., Lekht E.E., Mendoza-Torres J.E.,
Murakawa K., Rudnitskij G., Yates J.A.
<Astron. Astrophys. 546, A16 (2012)>
=2012A&A...546A..16R 2012A&A...546A..16R
ADC_Keywords: Stars, supergiant ; Masers
Keywords: masers - stars: AGB - stars: mass-loss - supergiants -
stars: winds, outflows - circumstellar matter
Abstract:
Cool, evolved stars undergo copious mass loss but the detailed
mechanisms and the form in which the matter is returned the ISM are
still under debate.
We investigated the structure and evolution of the wind at 5 to 50
stellar radii from Asymptotic Giant Branch and Red Supergiant stars.
Description:
Measurements of 22-GHz water maser clouds, made with the MERLIN radio
interferometer. Obects presented (number of epochs): S Per (2); U Ori
(4); U Her (3); IK Tau (3); RT Vir (7); W Hya (4). Results for VX Sgr
were presented in Murakawa et al, 2003, Cat. J/MNRAS/344/1. The
position and other properties of each patch of maser emission in each
channel were measured by fitting 2D Gaussian components. The
components form features corresponding to spatially distinct clouds
and the properties of each cloud was calculated as described in the
paper.
For each cloud, we give the mean Vlsr, the total velocity extent DV,
the full width half maximum DV1/2, the offsets of the cloud centroid
from the assumed stellar position x, y and a (=sqrt(x2+y2), the
feature largest angular size l and the peak flux density I. All
velocities, angular distances and flux densities are in km/s, mas and
Jy, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 79 7 Properties of the sample stars
appenb.dat 87 1190 H2O maser feature parameters
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See also:
J/MNRAS/344/1 : VX Sgr radially expanding molecular outflow (Murakawa+, 2003)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name (1)
8- 9 I2 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 18 F5.2 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs Declination (J2000)
32- 35 A4 --- Type Type of variable
37- 41 F5.1 km/s V* Stellar velocity, in LSR convention
43- 46 I4 pc Dist Distance
48- 50 I3 pc E_Dist Error in Dist (upper value)
52- 54 I3 pc e_Dist Error in Dist (lower value)
56- 59 I4 pc D Distance used for calculations
61- 63 F3.1 AU R* Stellar radius
65- 68 F4.2 AU e_R* rms uncertainty on R*
70- 72 I3 d Per Period
74- 79 E6.2 Msun/yr dM/dt Mass loss rate
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Note (1): Observations of VX Sgr are in Murakawa et al., 2003,
Cat. J/MNRAS/344/1.
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Byte-by-byte Description of file: appenb.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name
8- 17 A10 --- Date Observation date (YYYY or YYYY-MM-DD)
19- 23 F5.1 km/s Vlsr LSR velocity
25- 27 F3.1 km/s DV Full velocity extent of the feature, ΔV
29- 32 F4.2 km/s DV1/2 ?=0 Velocity FWHM of the feature, ΔV1/2 (1)
34- 37 F4.2 km/s e_DV1/2 ?=0 Velocity FWHM of the feature, ΔV1/2 (1)
39- 44 F6.1 mas x Cartesian (in the plane of the sky) offset
from the centre of expansion
46- 48 F3.1 mas e_x rms uncertainty on x
50- 55 F6.1 mas y Cartesian (in the plane of the sky) offset
from the centre of expansion
57- 59 F3.1 mas e_y rms uncertainty on y
61- 65 F5.1 mas a Radial (in the plane of the sky) offset
from the centre of expansion (a=sqrt(x2+y2))
67- 70 F4.1 mas e_a rms uncertainty on a
72- 75 F4.1 mas LAS Largest angular size of the feature
77- 80 F4.1 mas e_LAS rms uncertainty on LAS
82- 87 F6.2 Jy Ipeak Peak flux density of the feature, at 22GHz
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Note (1): set to zero if a Gaussian spectral profile could not be fitted
at ≥3sigma
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Acknowledgements:
Anita Richards, a.m.s.richards(at)manchester.ac.uk
(End) Patricia Vannier [CDS] 16-Jul-2012