III/132 Southern Galactic Carbon Stars - Near-IR Spectra (MacConnell 1988)
New Galactic Carbon Stars Found on Southern, Near-Infrared Spectrum Plates
MacConnell D.J.
<Astron. J, 96, 354 (1988)>
=1988AJ.....96..354M 1988AJ.....96..354M
ADC_Keywords: Stars, carbon
Abstract:
Over 400 cool carbon stars were found on near-infrared spectrum plates
of low-dispersion taken along the southern galactic plane. This
represents an approximate 10% increase in the number of such stars
known.
Introduction:
About 4000 optically detected carbon stars are known in the Galaxy,
largely concentrated toward the galactic plane and to galactocentric
distances greater than the solar circle, and significant numbers have
been detected in the Magellanic Clouds and other Local Group galaxies.
They are readily distinguished from stars of the normal, oxygen-rich
sequence by the presence of strong bands of diatomic carbon (the
defining characteristic) and of CN in their spectra, and the majority
of the galactic ones have been found on red and near- infrared (lambda
< 0.9 u) photographic plates taken with objective prisms mounted on
Schmidt telescopes.
In the early 1970's MacConnell began taking infrared plates of
dispersion 3400Å/mm at the A-band with the Curtis Schmidt telescope
at Cerro Tololo to search for cool supergiants and other stars of
interest. Plates were taken along the full galactic half-circle, from
l=210 to l=30, covering a band roughly 13 degrees wide centered on the
galactic plane. There are typically three unwidened I-N plates on each
5x5-degree field of 5 min, 30 min, and 60 min exposure; the deep
plates are ammonia-sensitized and reach I∼13. The spectra cover the
680-880nm region, and the features which distinguish carbon stars in
this region are the strong CN bands at 7945, 8125, and 832nm. In order
for a star to be classified as carbon, it must show C bands, but these
are present only blueward of the spectral range used. Stars with CN
bands strong enough to be seen at this low dispersion are invariably
carbon stars, usually of the cool N variety, but a survey of this type
will find relatively few of the weaker-banded stars of the warmer R
subtype.
Table I (file "catalog.dat") presents the new carbon stars found, in
order of R.A. 1950, as well as several dozen stars in Stephensons's
catalogue (column GCCCS) for which improved coordinates were obtained
in the present program. are accurate to about 5 arcsec in declination
and to about 3 arcsec in right ascension. The visual magnitudes are
estimated from a mean calibration applied to a set of direct, visual
region plates of 5min exposure taken with the same telescope, and the
error is probably of the order of 1mag.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 72 466 The catalog (table 1 of paper)
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/466] The number of the entry
5- 6 I2 h RA50h Right ascension hours (1950)
8- 9 I2 min RA50m Right ascension minutes (1950)
11- 14 F4.1 s RA50s Right ascension seconds (1950)
15 A1 --- u_RA50s [: ]Uncertainty flag on RA
16 A1 --- DE50- Declination sign (1950)
17- 18 I2 deg DE50d Declination degrees (1950)
20- 21 I2 arcmin DE50m Declination minutes (1950)
23- 24 I2 arcsec DE50s Declination seconds (1950)
25 A1 --- u_DE50s [: ]Uncertainty flag on Declination
26- 27 I2 h RA00h Right ascension hours (1900)
29- 30 I2 min RA00m Right ascension minutes (1900)
32- 35 F4.1 s RA00s Right ascension seconds (1900)
36 A1 --- u_RA00s [: ] Uncertainty flag on 1900 RA
37 A1 --- DE00- Declination sign (1900)
38- 39 I2 deg DE00d Declination degrees (1900)
41- 42 I2 arcmin DE00m Declination minutes (1900)
44- 45 I2 arcsec DE00s Declination seconds (1900)
46 A1 --- u_DE00s [: ]Uncertainty flag on 1900 dec.
47 A1 --- l_Vmag [><] Upper limit sign
48- 51 F4.1 mag Vmag ?Estimated V magnitude
52 A1 --- u_Vmag [: v] Uncertainty flag on Vmag
54 A1 --- u_GCCCS [u] 'u' for uncertain as a C star
55- 58 I4 --- GCCCS ?Number in Stephenson's catalog (III/36) (1)
60- 69 A10 --- IRAS IRAS name (cat. II/125)
70 A1 --- u_IRAS [?] Indicates uncertainty of IRAS designation
72 I1 --- n_ID [1/7]? Note (2)
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Note (1): Stephenson, Bruce, 1973 "A General Catalogue of Cool Carbon Stars"
Publ. Warner and Swasey Observ. Vol. 1, no. 4.
The GCCCS is uncertain ('u" flag) sour stars 372, 403, 415, and 425,
Note (2): the number has the following meaning:
1 = called carbon by Little-Marenin et al. (1987AJ.....93..663L 1987AJ.....93..663L),
on the basis of the IRAS low-resolution spectrum.
2 = This is GCCCS 736 = Westerlund 001-04 if Westerlund's RA
is 1min in error.
3 = Dec in GCCCS ibcorrect by 50yr precession value
4 = Called "symbiotic" by Weaver (1972PASP...84..854W 1972PASP...84..854W) and by
Sanduleak and Stephenson (1973ApJ...185..899S 1973ApJ...185..899S), table 1, no.38.
This is a third known galactic carbon symbiotic (Schulte-Ladbeck,
MacConnell abd Zarate 1987; in IAU Colloquium No.103)
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References:
Blanco, V.M., and Munch, L. (1955). Bol. Ton. y Tac. No. 12, p. 17.
Little-Marenin, I.R., Ramsay, M.E., Stephenson, C.B., Little, S.J., and
Price, S.D. (1987). Astron. J. 93, 663.
MacConnell, D.J., Landis, R.R., and Baker, P.B. (1985). Bull. Am.
Astron. Soc. 17, 877.
Nassau, J.J., and Velghe, A.G. (1964). Astrophys. J. 139, 190.
Stephenson, C.B. (1966). In Vistas in Astronomy 7, edited by A. Beer
(Pergamon, London), p.59.
Stephenson, C.B. (1973). A General Catalogue of Cool Carbon Stars (Publ.
of Warner and Swasey Obs., 1, No. 4.
Thronson, H.A., Jr., Latter, W.B., Black, J.H., Bally, J., and Hacking,
P. (1987). Astrophys. J. 322, 770.
Westerlund, B.E. (1971). Astron. Astrophys. Suppl. 4, 51.
(End) Nancy Grace Roman/Gail L. Schneider [ADC/SSDOO] 26-Feb-1996