J/A+AS/140/309 Blue-Hα objects in M33 (Fabrika+, 1999)
A survey of blue - Hα objects in the galaxy M33.
Fabrika S., Sholukhova O.
<Astron. Astrophys. Suppl. Ser. 140, 309 (1999)>
=1999A&AS..140..309F 1999A&AS..140..309F
ADC_Keywords: Galaxies, nearby ; Stars, early-type ; Stars, blue
Keywords: nearby galaxies: stellar content: individual (M33) -
stars: early type - Hα excess
Abstract:
For the purposes of a search for SS433 type objects, LBV stars and
hypergiants in M33, we have carried out a photometry of blue stars in
Hα images of this galaxy. From 2332 listed OB stars, we have
isolated 549 objects, which have Hα excess over stars of the
same V magnitude. Among them 81 emission stars (s) have been selected.
About 60% of isolated objects found to be extended in Hα, among
them 154 diffuse (d) and 180 bubble-type (b) nebulae. 117 objects are
compact (c) and faint Hα sources. These groups are different in
colour indices, Hα fluxes, surface brightness and sizes. The
most probable size of the Hα nebulae is FWHM=10-14pc. There
is evidence that their properties and location in the galaxy are
defined by interstellar gas pressure and related to spiral arms.
The d objects are HII regions with an embedded star. The b objects
are probably envelopes around WR stars or SN remnants. Among s-type
objects we isolated a group of 20 brightest stars, which in their
average properties fit well to the parameters of blue hypergiants or
LBV-type stars. The stars of intermediate brightness follow very well
to blue Ia supergiants. The interstellar absorption derived from
brightest Hα stars is AV=0.93±0.05mag. We classify the
faintest stars as blue Ib supergiants, their average absorption is
AV∼0.6mag. They are restricted in number by the limiting stellar
magnitude in the original sample.
Objects:
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RA (2000) DE Designation(s)
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01 33 54.0 +30 40 07 M 33 = NGC 598
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 29 549 Selected emission objects
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See also:
J/ApJS/89/85 : Blue and red supergiants in M33 (Ivanov+ 1993)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- FSZ [1/549] Sequential number
5- 8 I4 --- IFM-B Number of Ivanov et al., Cat. J/ApJS/89/85
10- 14 F5.2 mag Vmag V magnitude
16- 20 F5.1 --- S Hα excess parameter
22- 25 F4.1 arcsec Diam ? Diameter (objects too close to bright HII
regions could not be determined)
28- 29 A2 --- Morph Morphological type (1)
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Note (1): Morphological type as follows:
b = bubble-type
c = unclassified
d = diffuse
s = stellar
zs = objects for which it turned out to be impossible to determine
the size because of their closeness to bright HII regions
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History: From A&A electronic version
(End) Patricia Bauer [CDS] 26-May-2000