These notes provide for 114 stars of the catalogue a sort of "identity card'', i.e. a short summary of the most important results published over the past years. Our survey of the literature covers essentially the last decade. Although we have attempted to be as complete as possible in this compilation, it cannot be excluded that a few papers escaped our attention.
BAT99-1 (Brey 1): Due to the weakness of the NIV feature,
Conti & Massey (1989)
suggested that the spectral type WN2.5 or even WN2
could possibly be assigned to this star.
From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
.
;
(adopted);
;
.
The uncertainty results from the weakness of the HeI emission
line identified as a slightly increased continuum of 9 Å equivalent
width.
According to
Morris et al. (1993),
the continuum energy distribution of the
star can be fitted by a power law of the form , where
, over the range
. A
spectrum of the star in the range
is shown in Fig. 1
of the paper by
Morgan, Watson & Parker (1992).
BAT99-2 (Brey 2): This star lies in the HeIII region discovered within the N 79 nebula by Pakull (1991) who assigned to the star the earliest WN type: WN1. An image of the region is given by Melnick & Heydari-Malayeri (1991).
According to
Dopita et al. (1994),
the ring nebula associated with the star is 23'' in diameter, has similar
morphology to NGC 6888, and is brightest to the northwest. The HII region N 79 has a
fine filamentary loop about 3' in diameter.
Garnett & Chu (1994)
reported that the ejecta shell shows He and N
abundances identical to the LMC interstellar values.
BAT99-3 (Brey 3): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
. This star is a borderline WN3
(Smith et al. 1996).
BAT99-4 (Brey 3a): According to
Heydari-Malayeri et al. (1990),
the nebula N 82 presents chemical
abundances anomalies: nitrogen is enriched with
respect to the average LMC value by a factor of 5, whereas oxygen is depleted
by a factor 2.5. This very compact HII region seems to have been ejected by
the central WC9-type star which is likely to be a member of a binary
system, with an O-type companion. The ionizing source for N 82 is estimated
to have an absolute magnitude Mv = -4.5 and an effective temperature
.
Moffat (1991) argued that the emission-line spectrum of N 82 does not contain a WC9 spectrum, a WNL or Of spectrum appears more likely.
On the basis of new observations, Heydari-Malayeri & Melnick (1992) indicated that the central star (or stars) of N 82 does not seem to be a canonical WC9 subclass.
The object is designated as Brey 3a by
Lortet (1991).
BAT99-5 (Brey 4): No optical nitrogen ion lines being visible, Conti & Massey (1989) suggested that the spectral type WN1 could possibly be assigned to this star.
From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
.
;
(adopted);
;
.
The uncertainty results from the weakness of the HeI emission
line (
).
A spectrum of the star in the range is shown in Fig. 1
of the paper by
Morgan et al. (1992).
BAT99-6 (Brey 5): The star was classified O9f by
Ardeberg et al. (1972).
According to
Walborn (1977),
the broad HeII
and narrow NIV
emission present, indicate a WN component.
Dopita et al. (1994)
noted that the star is embedded in the filamentary
superbubble N 9; there is a filament of high excitation running in a
north-south direction which clearly passes close to the star. No
classical ring nebula is seen.
According to
Niemela et al. (1995),
the object appears to be a high-mass
() multiple system containing an eclipsing binary
(
2 days) which primary component is not of spectral type WN but
probably of type O3f*.
BAT99-7 (Brey 6):
Breysacher (1981)
classified this star as
peculiar because of the unusually broad emission lines.
Koesterke et al. (1991)
derived the following values for the "core
radius'' R*, the related effective temperature T*, the luminosity L and
the mass-loss rate of the star:
;
;
;
.
These authors point out that the spectrum exhibits a very strong HeII emission
at 5412 Å which has a larger equivalent width than the maximum reached in
their standard grid of models. Therefore, they had to perform special
calculations with 16 HeII levels for the analysis of this star.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-8 (Brey 8): Fehrenbach et al. (1976) noticed that star BE-159 is identified with WS 4 by Bohannan & Epps (1974) while on their finding chart the corresponding star is not WS 4.
Dopita et al. (1994)
reported the existence of a large, faint, previously
unrecognized ring nebula visible in [OIII], which is seen most clearly to the
north and to the southeast of the star. This ring is estimated to be in diameter.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-9 (Brey 7): Melnick & Heydari-Malayeri (1991) reported that an HeII image suggests the presence of a faint HeIII region near the star.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
A spectrum of this star is shown in Fig. 1c.
BAT99-10 (Brey 9): The multiple nature of this object was soon
recognized (cf.
Westerlund & Smith 1964).
The combined spectral type
O9.5II:+WC5 assigned by
Walborn (1977)
could be clarified thanks to the
speckle masking observations by
Schertl et al. (1995).
The core of the OB
association LH 9 was resolved into 25 stellar components in a field of view of
, and star No. 2 was identified without
ambiguity with the
component (see Fig. 2). Another study of this
cluster = HD32228 has been presented by
Bauer et al. (1996).
BAT99-11 (Brey 10): Fehrenbach et al. (1976) noticed that star BE-171 is identified with WS 6 by Bohannan & Epps (1974) while on their finding chart the corresponding star is not WS 6.
The star is in a superb ring nebula ( in diameter)
discovered by
Chu (1981);
it has a measured expansion velocity of
45 km s-1
(Chu 1983).
According to
Smith (1991),
this star is twice as bright, in line and
continuum, as any other WC4 star in the LMC.
BAT99-12 (Brey 10a): Star to which it is difficult to assign a unique
spectral type. The notation f* is used by
Walborn (1982a)
to indicate
that the NIV emission is stronger than NIII
.
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
BAT99-13:
Crowther et al. (1995)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
According to
Morris et al. (1993),
the continuum energy distribution of the
star can be fitted by a power law of the form , where
, over the range
.
A spectrum of the star in the range is shown
in Fig. 5 of the paper by
Bohannan & Walborn (1989).
BAT99-15 (Brey 12):
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Dopita et al. (1994)
reported the discovery of the true ring nebula
associated to this star, much a more compact filamentary shell, in
diameter, than the 8' across ring nebula claimed by
Chu & Lasker (1980).
BAT99-16 (Brey 13):
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther & Smith (1997)
obtained for these parameters:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Dopita et al. (1994)
reported the discovery of a fine ring nebula, only
in diameter, probably representing stellar ejecta.
Garnett & Chu (1994)
derived He/H and N/H in the ejecta shell
approximately a factor of two higher than the LMC HII region values,
and N/O more than a factor of 10 higher than the characteristic LMC value.
BAT99-17 (Brey 14): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-18 (Brey 15): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-19 (Brey 16): Breysacher (1981) classified the star as peculiar because of the unusually broad emission lines.
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found. According to
Dopita et al. (1994),
a faint filamentary nebula,
in diameter, is associated with the star and appears only in
[OIII].
BAT99-20 (Brey 16a): Dopita et al. (1994) noted that the star is surrounded by a small and bright ring nebula, 18'' in diameter, seen best in [OIII].
According to Bartzakos (1998), the absorption-line
spectrum might
arise in a visual OB companion, therefore the star is considered as
"almost certainly single''.
BAT99-21 (Brey 17): According to
Dopita et al. (1994),
there is a faint
nebula, 56'' in diameter, associated with the star.
BAT99-22 (Brey 18): According to Allen & Glass (1976), a late-type supergiant component provides the near-infrared flux. Cowley & Hutchings (1978) confirmed the presence of said component spectroscopically and classified it M2Ia. Stahl et al. (1984) found that the star is related to the S Dor variables. According to Crowther et al. (1995), the star is probably a dormant LBV, or at a stage immediately after this phase.
Schmutz et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
.
Crowther et al. (1995)
obtained very similar stellar
parameters:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
Dopita et al. (1994)
pointed out that the arcs of nebulosity seen in
H are not visible in [OIII].
Nota et al. (1996)
reported the presence of
strong nebular emission lines in the spectrum of BAT99-22 pointing
out, however, that on the basis of the spectroscopic data alone no
conclusion can be made about the physical association of the detected
nebula with the star.
A spectrum of the star in the range is shown in Fig. 3
of the paper by
Bohannan & Walborn (1989).
BAT99-23: This star (MG 9) was recently discovered by
Morgan (1999).
It is one of the faintest stars in the LMC, however
this unusual faintness is not intrinsic but due to extinction. The HeII
line is weaker than in most LMC WN3 stars.
BAT99-24 (Brey 19): According to
Dopita et al. (1994),
there is a large
ring nebula in both [OIII] and H, some
in
diameter, brightest to the southwest.
BAT99-25 (Brey 19a): This star, discovered by
Morgan & Good (1990),
lies outside the area searched by
Azzopardi & Breysacher (1980).
The object is designated as Brey 19a by
Lortet (1991)
who erroneously identified it as BE-456. The correct identification is BE-546.
BAT99-26 (Brey 20):
Dopita et al. (1994)
reported the discovery of a
very small ring nebula, in diameter, associated with the
star. A spectrum of this star is shown in Fig. 1a.
BAT99-27 (Brey 21): The star is located in an apparent association
which includes the compact cluster HD 35342, S Doradus (HD 35343) and HDE
269357
(Walborn 1977).
According to
Smith et al. (1996),
CIV HeII
indicates WN5 rather than WN3; a plateau of emission longward of HeII
is unidentified and unusual.
BAT99-28 (Brey 22): It is a confirmed binary system of period
P = 14.926 days
(Moffat et al. 1990);
a spectrum in the range is shown in Fig. 1 of their
paper.
According to
Dopita et al. (1994),
no nebular features appear to be
associated with the star.
BAT99-29 (Brey 23):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
Dopita et al. (1994)
confirmed that no nebular features are associated
with the
star itself.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-30 (Brey 24):
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther & Smith (1997)
obtained fairly similar stellar
parameters:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-31 (Brey 25):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-32 (Brey 26): According to Moffat (1989), it is a binary system of period P= 1.9075 days.
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther & Smith (1997)
obtained fairly similar stellar
parameters:
;
;
;
,assuming that the visual spectrum of the object is entirely due to the
star.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Dopita et al. (1994)
reported the discovery of a very small ring nebula,
16'' in diameter, which appears as a bright knot in H to the east of the
star, and as an arc of nebulosity to the south.
A spectrum of this star is shown in Fig. 1b.
BAT99-33: It is remarkable that this star, now classified
Ofpe/WN9, was already included in the list of stars recognised by
Miss Cannon and Miss Payne
(cf.
Buscombe et al. 1954).
Pasquali et al. (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Nota et al. (1996) reported the existence of a surrounding nebulosity.
A spectrum of the star in the range is shown in Fig. 4 of
the paper by
Bohannan & Walborn (1989).
BAT99-35 (Brey 27): From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the stellar parameters corresponding to the first
entry appear to be unrealistic given the WN3 spectral type of the star; the
presence of the HeI line is questioned.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Possibly a borderline WN4 according to
Smith et al. (1996).
BAT99-36 (Brey 29): The CIV emission line is unusually
strong for a WN-type star
(Breysacher 1981).
A spectrum of this star is shown
in Fig. 1a.
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther et al. (1995),
found very similar stellar
parameters from their standard model A analysis, however, in view of
the possible contamination of the line spectrum by a companion,
they performed a second analysis (model B) which takes into account
the binarity. The revised parameters then obtained are as follows:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Chu & Lasker (1980)
identified DEM 174 as a ring nebula, however,
according to
Dopita et al. (1994)
higher resolution images do not show any shell
structure.
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
BAT99-37 (Brey 30):
Dopita et al. (1994)
reported the discovery of a
small ring nebula, in diameter, extended in the north-south
direction.
BAT99-38 (Brey 31): It is a confirmed binary system of period
P = 3.03269 days
(Moffat et al. 1990);
a spectrum in the range is shown in Fig. 2 of their
paper.
Dopita et al. (1994)
reported the discovery of a
filamentary ring nebula, 33'' in diameter, visible in [OIII]. In H a
complex nebula in the form of a series of connected loops extends to the
south-southwest.
BAT99-39 (Brey 32): It is a confirmed binary system of period
P = 1.91674 days
(Moffat et al. 1990);
a spectrum in the range
is shown in Fig. 3 of their paper. According to
Seggewiss et al. (1991),
the orbital inclination is too
low to allow detectable transparency eclipses.
BAT99-40 (Brey 33): According to
Smith et al. (1996),
the spectrum
is heavily affected by an O absorption spectrum.
BAT99-41 (Brey 35): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-42 (Brey 34): Seggewiss et al. (1991) remarked that the fairly long spectroscopic period of this star (P=30.18: days) is still poorly known.
Dopita et al. (1994) reported the presence of a clearly defined filamentary ring nebula, 49'' in diameter, brightest in two arcs to the northwest and to the southeast.
According to
Smith et al. (1996),
CIV HeII
indicates WN5 rather than WN3; a plateau of emission longward of HeII
is unidentified and unusual.
BAT99-43 (Brey 37): From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the stellar parameters corresponding to the first
entry appear to be unrealistic given the spectral type of the star; the
presence of the HeI line is questioned.
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
Dopita et al. (1994)
reported the possible presence of a very faint,
small ring nebula in [OIII], 13'' in diameter, and brightest on the east side
of the star.
According to
Moffat (1998),
BAT99-43 is a short-period (SB2) binary system.
BAT99-44 (Brey 36):
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-45:
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
A spectrum of the star in the range is shown
in Fig. 3 of the paper by
Bohannan & Walborn (1989).
According to
van Genderen & Sterken (1996),
the observed light variations of
BAT99-45 show a timescale of 1-2 years and have an amplitude of
0.3-0.5 mag, which points to an LBV near minimum light. The colour
variation is also typical for an LBV.
BAT99-46 (Brey 38): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-48 (Brey 40):
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-49 (Brey 40a):
Niemela (1991)
found this object to be a
double-lined binary with an elliptic orbit (e=0.41) of period about 34
days.
Niemela et al. (1991)
also reported the detection of
nebular HeII line emission over a region having an extent of 70''.
According to
Dopita et al. (1994),
the star is surrounded by a circular ring nebula in
H
, some 40'' in diameter.
BAT99-52 (Brey 43): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-53 (Brey 44):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence for
nebular HeII
emission in the vicinity of the star could be
found. According to
Niemela (1995),
this star shows radial velocity variations
of emission and absorption lines in opposite sense indicating a long-period
binary.
BAT99-54 (Brey 44a):
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
BAT99-55:
Crowther & Smith (1997)
derived, from their model A analysis, the
following values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
A spectrum of the star in the range is shown
in Fig. 3 of the paper by
Bohannan & Walborn (1989).
According to
Nota et al. (1996),
the radial velocity map of the
circumstellar nebula ( in size, and showing a bipolar
morphology) is clearly consistent with a hollow shell expanding at
30 km s-1.
BAT99-56 (Brey 46): This star is noted as variable by Feitzinger & Isserstedt (1983).
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-58 (Brey 47):
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther & Smith (1997)
obtained fairly similar stellar
parameters:
;
;
;
A spectrum of the star in the range is shown in Fig. 1
of the paper by
Morgan et al. (1992).
BAT99-59 (Brey 48): From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the HeI emission is below safe
detection, therefore the determined temperature (first entry) corresponds to
the limit below which the HeI
line would start to become
visible.
A superb ring nebula studied by
Chu & Lasker (1980). According to
Dopita et al. (1994),
the inner filamentary ring of swept-up matter has a
diameter of , while the outer, more diffuse parts can be traced out
to a distance of 115'' from the exciting star.
BAT99-60 (Brey 49):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
BAT99-61 (Brey 50): According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-62 (Brey 51): A fine partial ring nebula, of diameter (Dopita et al. 1994),
appearing as a bright arc to the north of the star
was discovered by
Pakull (1991).
Possibly a borderline WN4 according to
Smith et al. (1996).
BAT99-63 (Brey 52): Cowley et al. (1984) found no evidence for binary motion, but noted the high velocity of the star, possibly a "runaway''.
From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the HeI emission is below safe
detection, therefore the determined temperature (first entry) corresponds to
the limit below which the HeI
line would start to become
visible.
A ring nebula was claimed for this object by
Chu & Lasker (1980).
According
to
Dopita et al. (1994),
they identified the bright HII region to the
northeast as a ring nebula, whereas it is apparent that the true nebula is a
fine filamentary ring in diameter.
BAT99-64 (Brey 53):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence for
nebular HeII
emission in the vicinity of the star could be
found.
BAT99-65 (Brey 55):
Dopita et al. (1994)
reported the discovery of a
ring nebula elongated in the northwest to southeast direction, in diameter. The outer filamentary shell has a fainter shell inside of
diameter 12''.
BAT99-67 (Brey 56): This star is noted as variable by Feitzinger & Isserstedt (1983). According to Smith et al. (1996) it is a binary with an OB component.
From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the HeI emission is below safe
detection, therefore the determined temperature (first entry) corresponds to
the limit below which the HeI
line would start to become
visible.
According to
Dopita et al. (1994),
there is a flocculent nebulosity associated
with the star, 40'' in diameter. This is contained within the X-ray
superbubble 0536-692
(Mathewson et al. 1985),
which is part of N 157.
BAT99-68 (Brey 58):
This star is located in the tight cluster in the western part of LH90. A
spectrum in the range
is shown in Fig. 2a of the paper
by
Testor et al. (1993)
who derived
a WN6-7 spectral type. The star is classified Of by
Smith et al. (1996).
BAT99-69: This star is located in the tight cluster in the western part
of LH90. A spectrum in the range
is
shown in Fig. 2b of the paper by
Testor et al. (1993).
BAT99-71 (Brey 60):
Smith et al. (1996)
pointed out that the HeII
emission lines are weak and very narrow for a WN3; they classified the star as
peculiar.
BAT99-76 (Brey 64): A spectrum of the star in the range
is shown in Fig. 3 of the paper by
Bohannan & Walborn (1989),
and in the
range
in Fig. 1b of the present paper.
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Crowther et al. (1995)
obtained fairly similar stellar
parameters:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Nota et al. (1996)
reported the existence of a surrounding shell which
expands at a velocity of km s-1. According to Pasquali,
Nota & Clampin (1998),
two diffuse arches define the shell of
diameter 13'', which is not of stellar origin and probably represents
the relic of the interstellar bubble blown by the star during its O
main-sequence phase.
BAT99-77 (Brey 65): This star is located in the tight cluster
= HD 269828 in the western
part of LH90.
Moffat (1989)
showed that the star is a binary
system with a period P = 3.0032 days. Spectral variations in the
range
are illustrated in Fig. 3 of the paper by
Heydari-Malayeri et al. (1993).
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-78 (Brey 65b): This star is located in the tight cluster = HD 269828
in the western part of LH90.
A spectrum in the range
is shown in Fig. 5 of the paper by
Testor & Schild (1990).
The object is designated as Brey 65b by Lortet (1991).
The composite nature of this star was recognized by
Heydari-Malayeri et al. (1993),
and confirmed by HST/WFC observations
(Walborn et al. 1995)
which further resolved the object into five
components. According to
Walborn et al. (1998),
the WN star is definitely
component 5C.
The HST image of BAT99-78 is reproduced in Fig. 8.
BAT99-79 (Brey 57): A spectrum of the star in the range
is shown in Fig. 3 of the paper by
Heydari-Malayeri et al. (1993).
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-80 (Brey 65c):
This star is located in the tight cluster = HD 269828 in LH90
and its spectrum, in the range
, is shown in Fig. 5 of the paper by
Testor & Schild (1990).
The object is designated as Brey 65c by
Lortet (1991).
BAT99-81 (Brey 65a): This star was discovered serendipitously
by
Cowley et al. (1984)
who reported a significant decrease in intensity of
the emission spectrum on one night (JD 2445732).
According to
Morris et al. (1993),
the continuum energy distribution of the
star can be fitted by a power law of the form , where
, over the range
.
BAT99-82 (Brey 66):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
A spectrum of the star in the range is shown in Fig. 1
of the paper by
Morgan, Watson & Parker (1992).
BAT99-83: This star is now categorized as a Luminous Blue
Variable. According to
Nota et al. (1991),
it is a very luminous
() star with an initial mass between
and
.
Smith et al. (1998)
found that the circumstellar environment of
BAT99-83 reveals two discrete ejections in the mass loss history of
the central star. There is an inner expanding shell, with a radius of
0.6 pc, an expansion velocity of 29 km s-1,and a dynamical age of
years. There is also material beyond the bright inner nebula that may
represent an outer expanding shell with a radius of 1.9 pc and a dynamical age of
years.
BAT99-84 (Brey 68): According to
Bartzakos (1998),
the absorption-line spectrum might arise in a visual OB companion,
therefore the star is considered as "almost certainly single''.
BAT99-85 (Brey 67): According to
Bartzakos (1998),
the
absorption-line spectrum might arise in a visual OB companion,
therefore the star is considered as "almost certainly single''.
BAT99-87 (Brey 70): According to
Bartzakos (1998),
the absorption-line spectrum might arise in a visual OB companion,
therefore the star is considered as "almost
certainly single''.
BAT99-88 (Brey 70a): According to
Lortet et al. (1991),
this star is
outstanding by its high luminosity (), high reddening,
strong and wide lines, and intense CIV
emission.
BAT99-89 (Brey 71):
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Dopita et al. (1994),
a dust arc - possibly a swept-up shell - appears 20'' to the north of the star in
projection against the bright HII region.
BAT99-90 (Brey 74): A spectrum of the star in the range
is shown in Fig. 1 of the paper by
Morgan et al. (1992).
BAT99-91 (Brey 73): This star is a complex multiple system in LH99
and was resolved into 12 components
by
Testor et al. (1988),
who achieved 0.25''
resolution. HST/WFC observations
of the object
(Walborn et al. 1995)
further resolved into four components each
the two brightest components, Nos. 1, (the WN) and 2, identified by
Testor et al. (1988).
According to
Walborn et al. (1998),
the WN star is definitely component 1A. The
HST image of BAT99-91 is reproduced in Fig. 10.
BAT99-92 (Brey 72): This star is noted as variable in V by
Feitzinger & Isserstedt (1983).
Although the component is generally
classified WN, the width of the HeII
emission and the
strength of the CIV
line probably explain that a WC type
has sometimes been assigned as well. The spectral type given in Table
2 is the one determined by
Moffat & Seggewiss (1986)
who argued that, unless one of the star has a very peculiar mass, the WN6
component must be orbiting a third, unseen star (P = 4.3092 days),
which is most likely a normal
luminosity O star of moderate mass, similar to the mass of the WN6
star.
Seggewiss et al. (1991)
remarked, however, that
the light curve shows no convincing evidence for variation with the
star's orbital period.
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
BAT99-93 (Brey 74a): The object is designated as Brey 74a by
Lortet (1991).
BAT99-94 (Brey 85): Breysacher (1981) classified this star as peculiar because of the unusually broad emission lines.
Koesterke et al. (1991)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
BAT99-95 (Brey 80):
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
Located in the vicinity of the core of 30 Doradus, BAT99-95 has a peculiar
spectral appearance among the WNL stars with strong, broad
non-Gaussian profiles.
According to
Dopita et al. (1994),
this star does
not appear to be associated with ring features.
BAT99-96 (Brey 81):
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
These authors noted that, relative to the other LMC WN8 stars,
BAT99-96 shows a high luminosity and very low hydrogen content of
H/He .
According to
Dopita et al. (1994),
this star does
not appear to be associated with ring features.
BAT99-98 (Brey 79): Star located near the core of
30 Doradus.
BAT99-99 (Brey 78): Star located near the core of
30 Doradus.
BAT99-100 (Brey 75): Star located near the core of 30 Doradus.
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
BAT99-101+102+103 (Brey 87): According to
Moffat et al. (1987),
the visual multiple system R 140, in the
30 Doradus nebula, contains at least
three stars, one of type WC5, the others of type WNL. BAT99-101
R 140a1 (northern component of R 140a) and BAT99-102
R
140a2 (southern component of R 140a) are not resolved on the
finding chart (Fig. 12). One of the WNL components
(BAT99-102) is found to be a close spectroscopic binary with a period of 2.76
days.
Dopita et al. (1994)
noted that the system does not appear to be
associated with ring features.
BAT99-104 (Brey 76): Star located near the core of
30 Doradus.
In the notation introduced by
Melnick (1985)
and refined by
Parker (1993),
the object is subdivided
into two components: Mk 37Wa and Mk 37Wb. According to
Massey & Hunter (1998),
the spectrum originates from Mk 37Wb.
BAT99-105 (Brey 77): Star located near the core of 30 Doradus.
Heap et al. (1991)
derived the following
properties for this star:
;
;
;
These authors noted that with a present mass of ,BAT99-105 is one of the most luminous and massive stars known. A
detailed NLTE analysis of this star has been presented by
de Koter et al. (1997).
BAT99-107 (Brey 86): Hyland et al. (1978) detected an infrared excess (V-K)0=1.41 for this star, which is much larger than normally found in galactic WN stars.
According to
Moffat (1989),
this object, which exhibits a "nonpure'' spectrum, is a spectroscopic binary. It appears to have been responsible for
producing a very bright and fine ring nebula,
in diameter,
brightest on the east and extending to the northwest
(Dopita et al. 1994).
BAT99-106+108+109+110+111+112 (Brey 82): Central cluster of 30 Dor. Speckle
interferometric observations
(Weigelt & Baier 1985)
and later HST/FOC images
(Weigelt et al. 1991)
have resolved R 136a - the bright, diffuse central
object - into a minimum of eight components (R 136a1a8), all
within 1''.
From HST spectroscopy,
Crowther & Dessart (1998)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the
stars:
BAT99-108 (R 136a1):
;
;
;
BAT99-109 (R 136a2):
;
;
;
BAT99-106 (R 136a3):
;
;
;
From HST observations (WFPC photometry and GHRS spectroscopy),
Heap et al. (1994)
derived the following properties for BAT99-110
(R 136a5) : ;
;
;
. These authors noted that the observed
mass-loss rate,
, is an order
of magnitude higher than assumed by current stellar evolutionary
models.
A detailed NLTE analysis of stars in R 136a has been presented by
de Koter et al. (1997).
BAT99-113: Star located near the core of 30 Doradus.
BAT99-114: Star located near the core of 30 Doradus.
BAT99-115 (Brey 83): Star located near the core of
30 Doradus.
In the notation introduced by
Melnick (1985)
and refined by
Parker (1993),
the object
is subdivided into three components: Mk 33Sa, Mk 33Sb and Mk 33Sc. The star corresponds to Mk 33Sb.
BAT99-116 (Brey 84): Star located near the core of
30 Doradus.
BAT99-117 (Brey 88): From an analysis of the helium spectrum,
Koesterke et al. (1991)
have derived
the following set of values for the "core radius'' R*, the related
effective temperature T*, the luminosity L and the mass-loss rate
of the star:
;
;
;
;
(adopted);
;
These authors point out that the HeI emission is below safe
detection, therefore the determined temperature (first entry) corresponds to
the limit below which the HeI
line would start to become
visible.
Dopita et al. (1994) noted that this star is contained within the X-ray-emitting supershell on the northeast side of 30 Dor.
According to
Smith et al. (1996),
strong Balmer absorption lines are present
in the spectrum, but no helium absorption lines.
BAT99-118 (Brey 89):
Crowther & Dessart (1998)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Dopita et al. (1994)
noted that this star is contained within the
X-ray-emitting supershell on the northeast side of 30 Dor.
BAT99-119 (Brey 90): According to Moffat (1989), it is a binary system of period P= 25.17: days.
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
These stellar parameters compare closely with those of BAT99-118, its
neighbour in 30 Doradus.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-120 (Brey 91):
Dopita et al. (1994)
reported the discovery of a
very large filamentary and "cellular'' ring nebula, in
diameter.
Possibly a post-LBV according to
Crowther et al. (1995)
who
derived the following stellar
parameters:
;
;
;
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
Nota et al. (1996)
reported the presence of
strong nebular emissions in the spectrum of BAT99-120 pointing
out, however, that the association of these lines with the star is
less obvious.
This star is located only 3'' west of Sk -69 249.
BAT99-122 (Brey 92): Hyland et al. (1978) detected an infrared excess (V-K)0= 2.10 for this star, which is much larger than normally found in galactic WN stars.
According to
Morris et al. (1993),
the continuum energy distribution of the
star can be fitted by a power law of the form , where
, over the range
.
Dopita et al. (1994)
noted that this star is contained within the
X-ray-emitting supershell on the northeast side of 30 Dor.
BAT99-123 (Brey 93): According to
Melnick & Heydari-Malayeri (1991),
the star is embedded in a bright HII region having a very complex structure in
[OIII]. The absence of HeII nebular emission in the ring nebula
around the star was noted by
Pakull (1991).
A spectrum of this star is shown in Fig. 1c.
BAT99-124 (Brey 93a):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence
for nebular HeII
emission in the vicinity of the star could be
found.
Dopita et al. (1994)
reported the discovery of a small asymmetric ring
nebula, in diameter, brightest to the east.
BAT99-126 (Brey 95): This star is noted as variable in V by Feitzinger & Isserstedt (1983).
Niemela et al. (1991)
reported that from their systematic
search for high excitation nebulae around stars in the Magellanic
Clouds, no evidence for nebular HeII
emission in the vicinity of the star
could be found.
BAT99-130:
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
A spectrum of the star in the range is
shown in Fig. 3 of the paper by
Bohannan & Walborn (1989).
BAT99-132 (Brey 99):
Niemela et al. (1991)
reported that from their systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence for
nebular HeII
emission in the vicinity of the star could be
found.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
BAT99-133: Walborn (1982b) considered this star to be a spectroscopic twin to R 127 (BAT99-83) in minimum.
Crowther & Smith (1997)
derived the following
values for the "core radius'' R*, the related effective temperature
T*, the luminosity L and the mass-loss rate of the star:
;
;
;
and obtained, after nebular subtraction, a relatively low hydrogen
content of H/He .
Pasquali et al. (1997)
obtained for these parameters:
;
;
;
Pasquali et al. (1998)
have spatially resolved the
circumstellar nebula associated wit BAT99-133. The nebula has the
appearance of a shell, 7.6'' in diameter, having a velocity expansion
of 28 km s-1, which indicates a dynamical age of 30000 years.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
A spectrum of the star in the range is
shown in Fig. 3 of the paper by
Bohannan & Walborn (1989).
BAT99-134 (Brey 100):
Niemela et al. (1991)
reported that from their
systematic search for high
excitation nebulae around stars in the Magellanic Clouds, no evidence for
nebular HeII
emission in the vicinity of the star could be
found.
According to
Morris et al. (1993),
the continuum
energy distribution of the star can be fitted by a power law of the form
, where
, over the range
.
Dopita et al. (1994)
noted that the fine ring nebula, in diameter, discovered by
Chu & Lasker (1980),
is embedded in a larger shell
structure.
Acknowledgements
We gratefully acknowledge the helpful support, comments and criticism of K.A. van der Hucht, G. Meylan, A.F.J. Moffat, D.H. Morgan and N.R. Walborn. We also wish to thank A. Gemmo and O. Hainaut for their assistance in the measurements of the star coordinates. We appreciate the valuable suggestions of the referee, Virpi Niemela, regarding the presentation.
Copyright The European Southern Observatory (ESO)