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III/132 Southern Galactic Carbon Stars - Near-IR Spectra (MacConnell 1988)
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New Galactic Carbon Stars Found on Southern, Near-Infrared Spectrum Plates
MacConnell D.J.
<Astron. J, 96, 354, (1988)>
=1988AJ.....96..354M
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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 disper-
sion 3400 A/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 6800-8800 A
region, and the features which distinguish carbon stars in this region
are the strong CN bands at 7945, 8125, and 8320 A. 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 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 5 min exposure taken
with the same telescope, and the error is probably of the order of 1
mag.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 71 466 The catalog
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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 The number of the entry
5- 6 I2 h RAh Right ascension hours (1950)
8- 9 I2 min RAm Right ascension minutes (1950)
11- 14 F4.1 s RAs Right ascension seconds (1950)
15 A1 --- u_RAs [: ]Uncertainty flag on RA
16 A1 --- DE- Declination sign (1950)
17- 18 I2 deg DEd Declination degrees (1950)
20- 21 I2 arcmin DEm Declination minutes (1950)
23- 24 I2 arcsec DEs Declination seconds (1950)
25 A1 --- u_DEs [: ]Uncertainty flag on Declination
26- 27 I2 h RAh0 Right ascension hours (1900)
29- 30 I2 min RAm0 Right ascension minutes (1900)
32- 35 F4.1 s RAs0 Right ascension seconds (1900)
36 A1 --- u_RAs0 [: ] Uncertainty flag on 1900 RA
37 A1 --- DE-0 Declination sign (1900)
38- 39 I2 deg DEd0 Declination degrees (1900)
41- 42 I2 arcmin DEm0 Declination minutes (1900)
44- 45 I2 arcsec DEs0 Declination seconds (1900)
46 A1 --- u_DEs [: ]Uncertainty flag on 1900 dec.
47 A1 --- gt [><] Upper limit sign
48- 51 F4.1 mag V ?Estimated V magnitude
52 A1 --- u_V [: v] Uncertainty flag on V
54- 57 I4 --- GCCCS *?Number in Stephenson's catalog
59- 63 I5 --- IRASh ?Right ascension part of IRAS number
64- 68 I5 --- IRASm ?Declination part of IRAS number
69 A1 --- u_IRASh [?] Indicates uncertainty in IRAS no.
71 I1 --- comp ?Component of multiple system
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Note on GCCCS:
Stephenson, Bruce, 1973 "A General Catalogue of Cool Carbon Stars"
Publ. Warner and Swasey Observ. Vol. 1, no. 4.
For stars 372, 403, 415, and 425, the GCCCS number is replaced by unc.
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.
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(End) Nancy Grace Roman/Gail L. Schneider [ADC/SSDOO] 26-Feb-1996