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CCD Photometry, Light Curve Modeling and Period Analysis of the Overcontact Eclipsing Binary BN Ari
Alton, K. B.; Nelson, R. H.; Boyd, D. R. S.
We present photometric and spectroscopic data of BN Ari, a totally eclipsing variable star. 15 new times-of-minimum have been determined. These along with other published eclipse timings were used to update the linear ephemeris and evaluate changes in orbital periodicity. Radial velocity data along with a definitive classification spectrum are rep…
New Galactic Multi-Mode Cepheids from the ASAS-SN Survey
Catelan, M.; Hajdu, G.; Jurcsik, J.
A systematic search for multi-mode Cepheids using the database of the ASAS-SN survey has led to the detection of thirteen new double-mode and two triple-mode Cepheids in the Galactic disk. These discoveries have increased the number of Galactic disk multi-mode Cepheids by 33%. One of the new triple-mode variables pulsates simultaneously in the fun…
Roche Modeling and Evolutionary History of Multiple Low Mass Contact Binary Systems
Stępień, K.; Alton, K. B.
The Northern Sky Variable Survey (NSVS) has been a rich source of variable stars many of which have only been studied to a limited extent. Herein we describe five eclipsing binary systems that were first detected by the ROTSE-I telescope and ultimately shown to be low mass contact binaries. Photometric data (B, V and Ic) acquired from M…
On the Distance Measurements in the Thin Milky Way Disk
Krełowski, J.; Galazutdinov, G. A.; Strobel, A. +2 more
We present a test how far the direct, trigonometric parallax measurements and those, based on interstellar CaII H and K lines lead to distances to OB stars similar to those, based on spectrophotometrically determined ones. For this we use relatively nearby objects where the extinction effects are negligible. A test is based on observations of inte…
Spectroscopy of the Eclipsing Binary BD-00°2862. Possible Multiplicity
Kamiński, K.; Dimitrov, W.; Polińska, M. +2 more
We present the first spectroscopic analysis of the eclipsing binary BD-00°2862. The All Sky Automated Survey light curves yield orbital period of the system of 2.15 d. The shape of the light curve reveals that the components are almost spherical and the binary is detached. The eclipses depths show significant difference of the components' temperat…
GT Ursae Majoris AB - a Possible Quadruple System
Kamiński, K.; Dimitrov, W.; Polińska, M. +3 more
We present the first spectroscopic study of an eclipsing system GT UMa. Our spectra show that the main visual component A is a triple-lined star, which consists of a close eclipsing pair and a farther third component. Radial velocity measurements show evidence of reflex motion. We used Hipparcos and our own R-band light curves for the analysis. Th…
Identification of V735 Sgr as an Active Herbig Ae/Be Object
Udalski, A.; Pietrukowicz, P.; Angeloni, R. +1 more
V735 Sgr was known as an enigmatic star with rapid brightness variations. Long-term OGLE photometry, brightness measurements in infrared bands, and recently obtained moderate resolution spectrum from the 6.5-m Magellan telescope show that this star is an active young stellar object of Herbig Ae/Be type.
The Appearance of Non-Spherical Systems. Application to LMXB
Różańska, A.; Madej, J.; Bełdycki, B. +2 more
We study the appearance of the neutron star-accretion disk system as seen by a distant observer in the UV/X-ray domain. The observed intensity spectra are computed assuming non-spherical geometry of the whole system, in which outgoing spectrum is not represented by the flux spectrum, the latter being valid for spherically symmetric objects. Intens…
On the Distance Measurements toward Young Milky Way Objects. I. Study of IC 2944
Krełowski, J.; Strobel, A.; Bondar, A. +1 more
We compare distances to a very young stellar aggregate, IC 2944, using three methods: direct parallaxes of Gaia, spectrophotometric parallax and our method based on intensities of interstellar CaII lines. The discrepancies between spectrophotometric distances and those, based on CaII K and H lines, were already reported. The interstellar CaII H an…
OGLE Study of the Sagittarius Dwarf Spheroidal Galaxy and its M54 Globular Cluster
Soszyński, I.; Udalski, A.; Szymański, M. K. +9 more
We use the fundamental-mode RR Lyr-type variable stars (RRab) from OGLE-IV survey to draw a 3D picture of the central part of the tidally disrupted Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy. We estimate the line-of-sight thickness of the Sgr dSph stream to be FWHMcen=2.42 kpc. Based on OGLE-IV observations collected in seasons 2011…