J/A+AS/127/185 SiO masers in OH/IR stars, proto-PN and PN (Nyman+ 1998)
SiO masers in OH/IR stars, proto-planetary and planetary nebulae
Nyman L.-A., Hall P.J., Olofsson H.
<Astron. Astrophys. Suppl. Ser. 127, 185 (1998)>
=1998A&AS..127..185N 1998A&AS..127..185N (SIMBAD/NED BibCode)
ADC_Keywords: Masers ; Planetary nebulae
Keywords: stars: AGB and post-AGB - masers - radio lines: stars
Abstract:
We present a search for SiO masers towards a sample of 126 objects
including OH/IR stars, proto-planetary and planetary nebulae. All
objects are classified as oxygen-rich, and most of them are associated
with OH or H2O masers. SiO masers were found only in variable
objects like the OH/IR stars and a few objects classified as
proto-planetary nebulae, but with variable central stars that may be
part of binary systems. In one object, OH 15.7+0.8, which appears to
be varying irregularly and most likely recently left the AGB, an SiO
maser was tentatively detected. Thus, we conclude that variability and
SiO maser emission are closely linked, and that SiO masers disappear
very soon after a star has reached the end of the AGB, when pulsation
and mass loss cease.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 87 128 Source parameters
table2 83 137 SiO maser observations
refs.dat 76 43 References
tables.tex 115 370 LaTeX version of the tables
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Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name
12- 25 A14 --- Names Other name
27- 28 I2 h RAh Right ascension (1950)
30- 31 I2 min RAm Right ascension (1950)
33- 36 F4.1 s RAs Right ascension (1950)
38 A1 --- DE- Declination sign
39- 40 I2 deg DEd Declination (1950)
42- 43 I2 arcmin DEm Declination (1950)
45- 46 I2 arcsec DEs Declination (1950)
48- 51 I4 km/s Vlsr LSR center velocity of the spectra
53 A1 --- OH [x] x: Presence of OH
55 A1 --- H2O [x] x: Presence of H2O
57 A1 --- SiO [xX?] x: Presence of SiO, X: new detection
59- 78 A20 --- Type Evolutionary status of the object (1)
80- 87 A8 --- r_Type References detailed in table refs.dat
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Note (1): OH/IR: objects with double-peaked OH spectra that have been found to
have variable OH, and/or optical, and/or infrared emission.
If no special monitor observations have been reported in the
literature, we regard an object as variable if the IRAS
variability index is>90. None of the characteristics given
below for PPNe have been reported for these objects.
PPN: objects that have one or more of the following characteristics:
bipolar appearance, an early type central star, a double
peaked energy distribution, high velocity masers, and/or the
velocity width of the H2O emission exceeds that of the OH
emission.
PN: Objects that have been detected in radio continuum, indicating
the presence of ionized gas.
variable star: Two objects where OH maser emission has not been detected,
but with variable central stars
supergiant: Two objects: IRAS 22480+6002 that has been classified as a
supergiant and IRC+10420 which may be a post-AGB object
or a supergiant.
PMS?: Five of the objects are more likely to be pre-main sequence
objects than evolved objects. These definitions cover 86% of
the sample.
?: The rest of the objects that do not fit into the above criteria
because of lack of relevant observations. We have not made any
attempt to separate them into possible OH/IR objects or PPNe,
although most of them probably are OH/IR objects.
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Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name
12- 18 I7 d HJD1 ? Epoch of observation of SiO v=1, J=1-0
20- 22 F3.1 Jy rms1 ? rms of SiO v=1, J=1-0
24- 28 F5.1 Jy peak1 ? Peak flux for SiO v=1, J=1-0 (1)
30- 33 F4.1 10-20W/m2 Int1 ? Int of SiO v=1, J=1-0
35- 41 I7 d HJD2 ? Epoch of observation of SiO v=2, J=1-0
43 A1 --- u_rms2 [*] *: Calibration is uncertain due to
unstable weather
45- 47 F3.1 Jy rms2 ? rms of SiO v=2, J=1-0
49- 53 F5.1 Jy peak2 ? Peak flux for SiO v=2, J=1-0 (1)
55- 59 F5.1 10-20W/m2 Int2 ? Int of SiO v=2, J=1-0
61 A1 --- n_HJD3 [*] *: Observation of SiO (2-1) made with
the Onsala 20 m telescope
63- 69 I7 d HJD3 ? Epoch of observation of SiO v=1, J=2-1
71- 73 F3.1 Jy rms3 ? rms of SiO v=1, J=2-1
75- 78 F4.1 Jy peak3 ? Peak flux for SiO v=1, J=2-1 (1)
80- 83 F4.1 10-20W/m2 Int3 ? Int of SiO v=1, J=2-1
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Note (1): Only the peak flux is given for tentatively detected sources.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- RefNo Reference number
5- 76 A72 --- Text Text of reference, including the Bibcode
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Acknowledgements: Lars-Ake Nyman
(End) Patricia Bauer [CDS] 18-Jul-1997