Wyniki wyszukiwania - Biblioteka Nauki

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The All Sky Automated Survey. The Catalog of Variable Stars in the Kepler Field of View

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Pigulski A. , Pojmański G. , Pilecki B. , Szczygieł D. M.

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2009

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tom Vol. 59, No. 1

33--46

EN

We present the catalog of 947 variable stars located in the field of view of the Kepler satellite. The catalog is a result of the analysis of VI photometry obtained during the first 17-month observations in the ASAS3-North station. The variable stars we present are divided into eleven groups according to the presented variability; the groups are briefly discussed. The catalog is intended to be a source of information for target selection process and follow-up programs.

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The All Sky Automated Survey. Catalog of Variable Stars. V. Declinations 0° - +28° of the Northern Hemisphere

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Pojmański G. , Pilecki B. , Szczygieł D.

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tom Vol. 55, No. 3

275--301

EN

This paper contains the fifth part of the Catalog of Variable Stars created from the V-band photometric data collected by 9°×9° camera of the All Sky Automated Survey. Preliminary list of variable stars found in the fields located between declination 0° and +28° of the northern hemisphere is presented. 11 509 stars brighter than V=15 mag were found to be variable (2 482 eclipsing, 1 397 regularly pulsating, 318 Miras and 7 310 other stars). Automated algorithm taking into account light curve properties (period, Fourier coefficients) and other available data (2MASS colors, IRAS fluxes) was applied to roughly classify the objects. This paper concludes our preliminary efforts to detect variable stars brighter than V≈14 mag over the sky south of declination +28°. A short summary of the current ASAS Catalog of Variable Stars is presented and links to the on-line data are provided. All the photometric data are available over the INTERNET at http://www.astrouw.edu.pl/~gp/asas/asas.html or http://archive.princeton.edu/~asas

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Large Magellanic Cloud Cepheids in the ASAS Data

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Karczmarek P. , Dziembowski W. A. , Lenz P. , Pietrukowicz P. , Pojmański G.

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tom Vol. 61, No. 4

303--318

EN

A catalog of Cepheids in the Large Magellanic Cloud (LMC) from the ASAS project is presented. It contains data on 65 fundamental mode pulsators with periods longer than about 8 days. The period-luminosity (PL) relation in the V-band does not significantly differ from the relation determined from the OGLE-III data extended toward longer periods but shows much larger scatter. For objects with periods longer than 40 d there is an evidence for a shallower PL relation. The rates of long-term period variations significant at 3σ level are found only for seven objects. The rates for 25 objects determined with the 1σ significance are confronted with the values derived from stellar evolution models. The models from various sources yield discrepant predictions. Over the whole data range, a good agreement with measurements is found for certain models but not from the same source.

4

Coronal Activity from the ASAS Eclipsing Binaries

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Szczygieł D. M. , Socrates A. , Paczyński B. , Pojmański G. , Pilecki B.

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tom Vol. 58, No. 4

405--418

EN

We combine the catalog of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalog, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L_X/L_bol≈ a few ×10^-4, similar to the ratio of soft X-ray to bolometric flux F_X/F in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs - stars with significant outer convection zones - a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called ``super-saturation'' phenomena. Our work shows that wide-field stellar variability searches can produce a high yield of binary stars with strong coronal activity.

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Discovery and Observations of the Unusually Luminous Type-Defying II-P/II-L Supernova ASASSN-13co

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Holoien T. W.-S. , Prieto J. L. , Pejcha O. , Stanek Z. , Kochanek C. S. , Shappee B. J. , Grupe D. , Morrell N. , Thorstensen J. R. , Basu U. , Beacom J. F. , Bersier D. , Brimacombe J. , Davis A. B. , Pojmański G. , Skowron D. M.

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tom Vol. 66, No. 2

219--238

EN

We present photometric and spectroscopic observations of ASASSN-13co, an unusually luminous Type II supernova and the first core-collapse supernova discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN). First detection of the supernova was on UT 2013 August 29 and the data presented span roughly 3.5 months after discovery. We use the recently developed model by Pejcha and Prieto to model the multi-band light curves of ASASSN-13co and derive the bolometric luminosity curve. We compare ASASSN-13co to other Type II supernovae to show that it was unusually luminous for a Type II supernova and that it exhibited an atypical light curve shape that does not cleanly match that of either a standard Type II-L or Type II-P supernova.