Absolute Magnitudes of Wolf-Rayet Stars: The WN3 and WN4 Sub-Classes in the Large Magellanic Cloud

10.1017/s0074180900010184 ◽

1975 ◽

Vol 67 ◽

pp. 147-147 ◽

Cited By ~ 1

Author(s):

Vicki E. Sherwood

Keyword(s):

Significant Variation ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Maximum Brightness ◽

Uv Excess ◽

Comparison Stars ◽

UBV observations of RCB stars with δ⩽30° were made at La Silla, Chile in the summer of 1972. Of 26 stars, 5 were below maximum brightness, including R CrB and RY Sgr. On the basis of a comparison of the dispersion in observations of the RCB stars and nearby non-variable comparison stars, 9 RCB stars were found to show significant variation at maximum brightness. They are W Men, UX Ant, UW Cen, DY Cen, AE Cir, S Aps, RT Nor, RZ Nor, and V CrA. The amplitude of these variations ranges from to and tentative periods from 19 to 54 days and > 90 days for S Aps. Similar variations at maximum are already known for R CrB, RY Sgr and XX Cam. Of the 5 stars which showed no significant variation at maximum, DZ And, Z Cir and V 973 Oph (see Orlov and Rodriguez, and Feast, this Symposium) are not RCB stars and SY Hyi is a questionable RCB star; only Y Mus is listed as a definite RCB variable.4 RCB stars in the Large Magellanic Cloud were observed: W Men, SY Hyi, HV 5637, and HV 12842. Absolute magnitudes at maximum of and respectively were derived. When plotted on a colour-colour diagram, most of these stars show an UV-excess for average colours at maximum. In the H-R diagram, they fall in a region where one would expect to find stars which are losing mass.

Absolute Magnitudes and Intrinsic Colours of Non-Supergiant Be Stars

10.1017/s0074180900037529 ◽

1982 ◽

Vol 98 ◽

pp. 33-36

Author(s):

J. R. Kozok

Keyword(s):

Absolute Magnitude ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Be Stars ◽

Large Sample ◽

Galactic Clusters ◽

Absolute Magnitudes ◽

Image Position ◽

Intrinsic Colour

101 normal Be stars, probable members of 56 galactic clusters and OB-associations, and more than 20 extreme Be stars in the Large Magellanic Cloud were used to derive intrinsic colours of 09-B9 (III-V)e stars. Furthermore, the correlation between the intrinsic colour (U-B)0 and the absolute magnitude of non-supergiant Be stars was confirmed to be and The aim of the present investigation is to enlarge the basis for the determination of intrinsic colours and absolute magnitudes by providing a large sample from the southern sky.

Calibration En Magnitudes Absolues De La Classification BCD. Application à La Détermination Du Module De Distance Du Grand Nuage De Magellan

10.1017/s007418090005511x ◽

1973 ◽

Vol 54 ◽

pp. 78-85

Author(s):

L. Divan

Keyword(s):

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Distance Modulus ◽

Rr Lyrae ◽

A Value ◽

Cepheid Variables ◽

The calibration of the BCD stellar classification in absolute magnitudes (classification in three parameters λ1, D, Φb) was used to determine the distance modulus of the Large Magellanic Cloud. The described method makes use of the spectrophotometric parameters of B and A supergiants of the Large Cloud and gives a value of the distance modulus which is independent from other determinations, in particular from those which are based on the RR Lyrae and the Cepheid variables. The value found for the distance is slightly smaller than those generally admitted. The results are still based only on a limited number of measurements and new observations are in process; however, it seems doubtful that one will obtain much larger values. In other respects, the observations have shown that the parameter λ1 was still sensitive to luminosity for the B and A stars brighter than M = −8 and that the calibration of the λ1D diagram in absolute magnitudes can be extended up to M = −9.

Absolute Magnitudes of Wolf-Rayet Stars: The WN3 and WN4 Sub-Classes in the Large Magellanic Cloud

10.1017/s0074180900029302 ◽

1982 ◽

Vol 99 ◽

pp. 523-526

Author(s):

Jacques Breysacher ◽

Marc Azzopardi

Keyword(s):

Hii Regions ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Private Communication ◽

Systematic Survey ◽

The Core ◽

Objective Prism ◽

After the systematic survey carried out by Azzopardi and Breysacher (1979, 1980) at La Silla, Chile, with the 40-cm Objective Prism Astrograph, the census of the Wolf-Rayet population (101 stars) in the Large Magellanic Cloud (LMC) can probably be considered as quite complete except, perhaps, for stars located in the core of dense HII regions. The catalogue by Breysacher (1981) includes 100 stars to which one has to add one star of the WN type discovered by Sanduleak (private communication) outside of the survey limits.

Star Density Distribution in Young and Old Globular Clusters of the Large Magellanic Cloud

10.1017/s0074180900092111 ◽

1980 ◽

Vol 85 ◽

pp. 341-341

Author(s):

E. H. Geyer ◽

U. Hopp ◽

M. Kiehl ◽

S. Witzigmann

Keyword(s):

Density Distribution ◽

Globular Clusters ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Schmidt Telescope ◽

Star Density ◽

The star density distribution in NGC 1818, 2004, 1806 and 1846, which are representative for the “blue” and “red” globular clusters of the LMC, have been determined from star counts on B- and V- ESO Schmidt telescope plates. These have limiting magnitudes of about 21, thus stars with absolute magnitudes of about Mv ~ +2 are reached. It was found that the two cluster types can be treated as “polytropic stargas spheres” according to the Schuster law with an index n ~ 2.75.

Color excesses, intrinsic colors, and absolute magnitudes of Galactic and Large Magellanic Cloud Wolf-Rayet stars

The Astrophysical Journal Supplement Series ◽

10.1086/191485 ◽

1990 ◽

Vol 73 ◽

pp. 685 ◽

Cited By ~ 28

Author(s):

William D. Vacca ◽

Ana V. Torres-Dodgen

Keyword(s):

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Distance to SN 1987A and the LMC

10.1017/s0074180900118959 ◽

1999 ◽

Vol 190 ◽

pp. 549-554

Author(s):

Nino Panagia

Keyword(s):

Angular Size ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Light Curves ◽

Distance Modulus ◽

Absolute Size ◽

Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

Novae in the Magellanic Clouds

International Astronomical Union Colloquium ◽

10.1017/s0252921100073334 ◽

1979 ◽

Vol 46 ◽

pp. 96-101

Author(s):

J.A. Graham

Keyword(s):

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Magellanic Clouds ◽

University Of Michigan ◽

The Past ◽

Spectroscopic Information ◽

Objective Prism ◽

The University ◽

Small Cloud ◽

Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).