scholarly journals CCD Photometry of the Eclipsing Binary HV 2274 in the Large Magellanic Cloud

1992 ◽  
Vol 151 ◽  
pp. 509-513
Author(s):  
R.D. Watson ◽  
S.R.D. West ◽  
William Tobin ◽  
A.C. Gilmore
Keyword(s):  
New Zealand ◽  
Orbital Period ◽  
Large Magellanic Cloud ◽  
Current Data ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Eccentric Orbit ◽  
Ccd Photometry ◽  
Eclipsing Binary ◽  
Data Points

B, V and Ic photometry of the eclipsing binary HV 2274, located in the LMC, was obtained with the CCD system at the Mount John University Observatory, Lake Tekapo, New Zealand during 1990. Over 100 data points were acquired in each filter to an estimated precision of 0.02 mag. The flat maxima evident in the light curves suggest that the system, which is currently classed as an interacting candidate, should probably be considered as a detached one. A revised orbital period based on the inclusion of current data is presented. Eclipse timings indicate an eccentric orbit. An apsidal period in the vicinity of 120 yr is likely.

scholarly journals The multiple system Sk-67°18 in the LMC

1995 ◽  
Vol 163 ◽  
pp. 251-253 ◽  
Author(s):  
V. S. Niemela ◽  
W. Seggewiss ◽  
A. F. J. Moffat
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Spectral Type ◽  
Orbital Period ◽  
Large Magellanic Cloud ◽  
Primary Component ◽  
Magellanic Cloud ◽  
Bright Star ◽  
High Mass ◽  
Eclipsing Binary

The bright star Sk—67°18 (Brey 5) in the Large Magellanic Cloud (LMC) contains an eclipsing binary system. Our radial velocity study reveals that the orbital period is almost exactly two days. The spectra also show that the star's primary component is not of spectral type WN, but that the star is rather an Of+O type binary where the primary is probably of type O3f*. Furthermore, Sk—67°18 appears to be a high-mass multiple system.

scholarly journals The Wolf-Rayet Eclipsing Binary HD 5980 in the Small Magellanic Cloud

1982 ◽  
Vol 99 ◽  
pp. 317-320
Author(s):  
Jacques Breysacher ◽  
Anthony F. J. Moffat ◽  
Virpi S. Niemelä
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Orbital Period ◽  
Spectroscopic Data ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Eccentric Orbit ◽  
Eclipsing Binary ◽  
Hii Region ◽  
Rayet Star

The Wolf-Rayet star HD 5980, which is probably associated with the bright HII region NGC 346 of the Small Magellanic Cloud, was found to be an eclipsing binary by Hoffmann, Stift and Moffat (1978). Breysacher and Perrier (1980) determined the orbital period, P=19.266±0.003d, of the system whose light curve reveals a strongly eccentric orbit (e=0.47 for i=80°). The behaviour of the light curve outside the eclipses shows that we are dealing with a rather complex binary system. An analysis of the spectroscopic data is presented here.

Distance to SN 1987A and the LMC

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.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

scholarly journals Light Curves and Metal Abundances of RR Lyrae Variables in the Bar of the Large Magellanic Cloud

2000 ◽  
Vol 176 ◽  
pp. 172-175 ◽  
Author(s):  
G. Clementini ◽  
A. Bragaglia ◽  
L. Di Fabrizio ◽  
E. Carretta ◽  
R. G. Gratton
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Photometric System ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Visual Magnitude ◽  
Metal Abundance ◽  
Definition Of ◽  
Lyrae Stars

AbstractThe Large Magellanic Cloud (LMC) is widely considered a corner-stone of the astronomical distance scale. However, a difference of 0.2−0.3 mag exists in its distance as predicted by the short and long distance scales. Distances to the LMC from Population II objects are founded on the RR Lyrae variables. We have undertaken an observational campaign devoted to the definition of the average apparent luminosity, and to the study of the mass–metallicity relation for RR Lyrae stars in the bar of the LMC. These are compared with analogous quantities for cluster RR Lyrae stars. The purpose is to see whether an intrinsic difference in luminosity, possibly due to a difference in mass, might exist between field and cluster RR Lyrae stars, which could be responsible for the well-known dichotomy between short and long distance scales. Preliminary results are presented on the V and B − V light curves, the average apparent visual magnitude, and the pulsational properties of 102 RR Lyrae stars in the bar of the LMC, observed at ESO in January 1999. The photometric data are accurately tied to the Johnson photometric system. Comparison is presented with the photometry of RR Lyrae stars in the bar of the LMC obtained by the MACHO collaboration (Alcock et al. 1996). Our sample includes 9 double-mode RR Lyrae stars selected from Alcock et al. (1997) for which an estimate of the metal abundance from the ΔS method is presented.

scholarly journals A photometric and spectroscopic study of R Coronae Borealis stars in the LMC

1991 ◽  
Vol 148 ◽  
pp. 351-352
Author(s):  
W. A. Lawson ◽  
P. L. Cottrell ◽  
K. R. Pollard
Keyword(s):  
High Resolution ◽  
Spectroscopic Study ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Photometric Observations ◽  
R Coronae Borealis Stars

Over the last several years we have obtained photometric observations of the four suspected (W Men, HV 5637, HV 12671, HV 12842) R Coronae Borealis (RCB) stars in the Large Magellanic Cloud (LMC). Fourier analyses of the light curves has revealed some periodicity in HV 12842, where there appear to be at least two closely spaced periods of 55 and 60 d. High resolution spectra of HV 12842, obtained with the Ango-Australian Telescope (AAT), indicate that it has similar atmospheric properties to a number of warmer galactic RCB and hydrogen-deficient Carbon (HdC) stars, e.g. R CrB, RY Sgr and XX Cam.

Cepheid Variables in the Large Magellanic Cloud Cluster NGC 1866. I. New BVRI CCD Photometry

2000 ◽  
Vol 129 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Wolfgang P. Gieren ◽  
Matias Gomez ◽  
Jesper Storm ◽  
Thomas J. Moffett ◽  
L. Infante ◽  
...  
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Ccd Photometry ◽  
Cloud Cluster ◽  
Cepheid Variables
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