M. Winiarski

Pedagogical University of Cracow, Cracovia, Lesser Poland Voivodeship, Poland

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Publications (51)141.65 Total impact

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    ABSTRACT: Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical properties of main-belt asteroids or large collisional families. We aim to increase the number of asteroid shape models and rotation states. Such results are an important input for various further studies such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides, in combination with known masses, bulk density estimates, but constrains also theoretical collisional and evolutional models of the Solar System. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as an input for the convex inversion method, and derive 3D shape models of asteroids, together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that one hundred observers who submit their optical data to publicly available databases. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature or their masses will be most likely determined from their gravitational influence on smaller bodies, which orbital deflection will be observed by the ESA Gaia astrometric mission. This was achieved by using additional optical data from recent apparitions for the shape optimization. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and 3 near-Earth asteroids.
    Full-text · Article · Nov 2015 · Astronomy and Astrophysics
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    ABSTRACT: We report new BVRI photometric observations of an eclipsing, massive binary V729 Cyg taken between 2008 and 2011. We performed light curve modeling of the new data and those available in the literature using the Wilson-Devinney code. The best fit was obtained for a contact configuration, similarly to results derived previously by other investigators. However, a huge temperature difference of about 10 000K-12 000K was derived, inconsistent with theoretical calculations. Ruling out a possibility of V729 Cyg being a semi-detached system harbouring an accretion disk, we determined physical parameters of components.
    No preview · Article · Jan 2014
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    ABSTRACT: By using 78 newly determined timings of light minima together with those collected from the literature, we analysed the changes in the observed minus calculated (O−C) diagram in HS 0705+6700, a short-period (2.3 h) eclipsing binary that consists of a very hot subdwarf B-type (sdB) star and a very cool fully convective red dwarf. We confirmed the cyclic variation in the O−C and refined the parameters of the circumbinary brown dwarf (reported to orbit the binary system in 2009) by analysing the changes for the light travel time effect that arises from the gravitational influence of the third body. Our results indicate the lower mass limit of the third body to be M3 sin i′ = 33.7(±1.6) MJup. This companion would be a brown dwarf if its orbital inclination is larger than 27 $_{.}^{\circ}$7 and it is orbiting the central eclipsing binary with an eccentricity e ∼ 0.2 at a separation of about 3.7(±0.1) au.
    No preview · Article · Dec 2013 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending towards the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z_c = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.
    Full-text · Article · Dec 2012 · The Astrophysical Journal
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    ABSTRACT: Data were obtained from six different observatories, each with a somewhat different CCD setup. South African Astronomical Observatory's (SAAO's) 1.0-m telescope observed during both 2008 and 2009. (1 data file).
    No preview · Article · Oct 2012
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    ABSTRACT: Two observational campaigns were carried out during the eclipses of EE Cep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depth and durations of the eclipses. Multicolour photometric data and spectroscopic observations at both low and high resolution were collected. We numerically modelled the variations in brightness and colour during the eclipses. We tested models with different disk structure. We considered the possibility of disk precession. The complete set of observational data collected during the last three eclipses are made available to the astronomical community. Two blue maxima in the colour indices were detected during these two eclipses, one before and one after the photometric minimum. The first (stronger) blue maximum is simultaneous with a "bump" that is very clear in all the UBVRI light curves. Variations in the spectral line profiles seem to be recurrent during each cycle. NaI lines always show at least three absorption components during the eclipse minimum and strong absorption is superimposed on the H_alpha emission. These observations confirm that the eclipsing object in EE Cep system is indeed a dark, dusty disk around a low luminosity object. The primary appears to be a rapidly rotating Be star that is strongly darkened at the equator and brightened at the poles. Some of the conclusions of this work require verification in future studies: (i) a complex, possibly multi-ring structure of the disk in EE Cep; (ii) our explanation of the "bump" observed during the last two eclipses in terms of the different times of obscuration of the hot polar regions of the Be star by the disk; and (iii) our suggested period of the disk precession (~11-12 P_orb) and predicted depth of about 2 mag the forthcoming eclipse in 2014.
    Full-text · Article · Apr 2012 · Astronomy and Astrophysics
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    ABSTRACT: We present the results of the study of the contact binary system BO CVn. We have obtained physical parameters of the components based on combined analysis of new, multi-color light curves and spectroscopic mass ratio. This is the first time the latter has been determined for this object. We derived the contact configuration for the system with a very high filling factor of about 88 percent. We were able to reproduce the observed light curve, namely the flat bottom of the secondary minimum, only if a third light has been added into the list of free parameters. The resulting third light contribution is significant, about 20-24 percent, while the absolute parameters of components are: M1=1.16, M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward parabola which, under the conservative mass transfer assumption, would correspond to a mass transfer rate of dM/dt = 6.3 \times 10-8M\odot/yr, matter being transferred from the less massive component to the more massive one. No cyclic, short-period variations have been found in the O-C diagram (but longer-term variations remain a possibility)
    Full-text · Article · Apr 2012 · New Astronomy
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    ABSTRACT: We report on an analysis of 308.3 hr of high-speed photometry targeting the pulsating DA white dwarf EC14012-1446. The data were acquired with the Whole Earth Telescope during the 2008 international observing run XCOV26. The Fourier transform of the light curve contains 19 independent frequencies and numerous combination frequencies. The dominant peaks are 1633.907, 1887.404, and 2504.897 μHz. Our analysis of the combination amplitudes reveals that the parent frequencies are consistent with modes of spherical degree l = 1. The combination amplitudes also provide m identifications for the largest amplitude parent frequencies. Our seismology analysis, which includes 2004-2007 archival data, confirms these identifications, provides constraints on additional frequencies, and finds an average period spacing of 41 s. Building on this foundation, we present nonlinear fits to high signal-to-noise light curves from the SOAR 4.1 m, McDonald 2.1 m, and KPNO 2 m telescopes. The fits indicate a time-averaged convective response timescale of τ0 = 99.4 ± 17 s, a temperature exponent N = 85 ± 6.2, and an inclination angle of θi = 329 ± 32. We present our current empirical map of the convective response timescale across the DA instability strip.
    Full-text · Article · Apr 2012 · The Astrophysical Journal
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    ABSTRACT: This paper presents the results of the analysis of (O-C) diagrams of four eclipsing variables. The diagrams are based on times of minima collected in the Cracow database, which contains times of minima found in the literature, from observations at Mt. Suhora and Ulupinar Observatories, or determined using publicly-available photometric surveys (NSVS, ASAS etc).
    Full-text · Article · Apr 2012 · Proceedings of the International Astronomical Union
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    ABSTRACT: OJ287 is being monitored in the optical waveband with small telescopes at the Astronomical Observatory of the Jagiellonian University (KRK) and the Mt. Suhora Observatory of the Pedagogical University (SUH) in Poland, and at the University of Athens, Greece (ATH). On April 19th, Mt. Cuba Observatory, USA (MTC), performed additional observations of this target. We report an even higher optical state of OJ287 than that published in Atel #4020 and Atel #4021.
    No preview · Article · Apr 2012
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    ABSTRACT: We have analyzed the available spectra of WW And and for the first time obtained a reasonably well defined radial velocity curve of the primary star. Combined with the available radial velocity curve of the secondary component, these data led to the first determination of the spectroscopic mass ratio of the system at q-spec = 0.16 +/- 0.03. We also determined the radius of the accretion disc from analysis of the double-peaked H-alpha emission lines. Our new, high-precision, Johnson VRI and the previously available Stromgren vby light curves were modelled with stellar and accretion disc models. A consistent model for WW And - a semidetached system harbouring an accretion disc which is optically thick in its inner region, but optically thin in the outer parts - agrees well with both spectroscopic and photometric data.
    Full-text · Article · Mar 2012 · New Astronomy
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    ABSTRACT: We present follow-up observations of the pulsating subdwarf B (sdB) star EC 01541–1409 as part of our efforts to resolve pulsation spectra for use in asteroseismological analyses. This paper reports on data obtained from a single-site campaign, during 2008, and a multisite campaign, during 2009. From limited 2008 data, we were able to clearly resolve and pre-whiten 24 periods. A subsequent multisite campaign spanning nearly 2 months found over 30 individual periodicities most of which were unstable in amplitude and/or phase. Pulsation amplitudes were found to the detection limit, meaning that further observations would likely reveal more periodicities. EC 01541–1409 reveals itself to be one of two sdB pulsators with many pulsation frequencies covering a large frequency range. Unlike the other star of this type (PG 0048+091), it has one high-amplitude periodicity which appears phase stable, making EC 01541–1409 an excellent candidate for exoplanet studies via pulsation phases. No multiplets were detected leaving EC 01541–1409 as yet another rich p-mode sdB pulsator without these features, limiting observational constraints on pulsation modes.
    Preview · Article · Mar 2012 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: PG 1351+489 is one of the 20 DBVs - pulsating helium-atmosphere white dwarf stars - known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for the main peak at 489.334 48 s and two other normal modes using data from the Whole Earth Telescope (WET) observations of 1995 and 2009. In 2009, we detected a new pulsation mode and the main pulsation mode exhibited substantial change in its amplitude compared to all previous observations. We were able to estimate the star's rotation period, of 8.9 h, and discuss a possible determination of the rate of period change of (2.0 +/- 0.9) x 10(-13) s s(-1), the first such estimate for a DBV.
    Full-text · Article · Aug 2011 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The Mt. Suhora M\,dwarf survey searching for pulsations in low mass main sequence stars has acquired CCD photometry of 46 M\,dwarf stars during the first year of the project (Baran et al 2011). As a by-product of this search hundreds field stars have been checked for variability. This paper presents our initial result of a search for periodic variables in field stars observed in the course of the survey. On the basis of the periodicity and the shape of the light curves, eight new variables has been detected, among which five are $\delta$ Scuti stars and three likely RR Lyrae stars. Although variation in one of the stars has been previously detected, it was classified incorrectly. To support our classification, in August 2010, we performed spectroscopic observations to derive spectral types and luminosity classes for all eight variable stars.
    Full-text · Article · Jun 2011 · New Astronomy
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    ABSTRACT: We present the first results of our M dwarf survey in search for stellar pulsation in low mass main sequence stars. Theoretical calculations predict that ɛ mechanism might drive a fundamental radial mode in these stars and therefore pulsations could be observed photometrically. Although M dwarfs are known for their flare and spot activity they have not yet been the subject of dedicated time-series surveys for pulsation. In this work we include the light curves and amplitude spectra of 46 M dwarfs, which have been observed during the first two years of our survey. We did not detect any pulsations yet. As a by-product of our search, we describe the light curves of some flare M dwarfs. The survey will last for two more years and during that period more than a hundred of M0-M4 type main sequence stars will be observed.
    No preview · Article · Mar 2011 · Acta Astronomica -Warsaw and Cracow-
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    ABSTRACT: The sudden lengthening of orbital period of VV Cep eclipsing binary by about 1% was observed in the last epoch. The mass transfer and/or mass loss are most possible explanations of this event. The photometric behaviour of AZ Cas, the cousin of VV Cep, suggests that the accretion can occur and could be important in this system, too.
    Full-text · Article · Feb 2011
  • A. Erdem · S. Zola · M. Winiarski
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    ABSTRACT: This paper presents the absolute parameters of RZ Dra. New CCD observations were made at the Mt. Suhora Observatory in 2007. Two photometric data sets (1990 BV and 2007 BVRI) were analysed using modern light-curve synthesis methods. Large asymmetries in the light curves may be explained in terms of a dark starspot on the primary component, an A6 type star. Due to this magnetic activity, the primary component would appear to belong to the class of Ap-stars and would show small amplitude with δ Scuti-type pulsations. With this in mind, a time-series analysis of the residual light curves was made. However, we found no evidence of pulsation behaviour in RZ Dra. Combining the solutions of our light curves and Rucinski et al. (2000)’s radial velocity curves, the following absolute parameters of the components were determined: M1 = 1.63 ± 0.03 M⊙, M2 = 0.70 ± 0.02 M⊙, R1 = 1.65 ± 0.02R⊙, R2 = 1.15 ± 0.02 R⊙, L1 = 9.72 ± 0.30 L⊙ and L2 = 0.74 ± 0.10 L⊙. The distance to RZ Dra was calculated as 400 ± 25 pc, taking into account interstellar extinction. The orbital period of the system was studied using updated O–C information. It was found that the orbital period varied in its long-period sinusoidal form, superimposed on a downward parabola. The parabolic term shows a secular period decrease at a slow rate of 0.06 ± 0.02 s per century and is explained by the mass loss via magnetized wind of the Ap-star primary. The tilted sinusoidal form of the period variation may be considered as an apparent change and may be interpreted in terms of the light-time effect due to the presence of a third body.
    No preview · Article · Jan 2011 · New Astronomy
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    ABSTRACT: To understand the properties of orbital period changes of four short period sdB-type eclipsing binaries, HW Vir, HS 0705 + 6700, HS 2231 + 2441, and NSVS 14256825, we have monitored them photometrically since 2006. Apart from HW Vir, it is found that the O–C diagrams of HS 0705 + 6700 and HS 2231 + 2441 can also be described by a cyclic variation superimposed on a downward parabolic curve, indicating a long-term period decrease in the two systems. Therefore, of the four binary systems, long-term period variations have been detected for three ones that can be explained by magnetic braking of the fully convective component stars. This may drive these systems to evolution into normal cataclysmic variables. As for the cyclic period variations observed in the four systems, the light-travel time effect via the presence of a tertiary component is the most possible mechanism to interpret the periodic change, which reveals the presence of extremely low-mass objects (e.g., brown dwarf stars and huge planets) in this kind of binaries. KeywordsStars: binaries: close-Stars: binaries: eclipsing-Stars: subdwarfs-Stars: low-mass, brown dwarfs-Stars: mass-loss
    No preview · Article · Oct 2010 · Astrophysics and Space Science
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    ABSTRACT: We present results of the modelling of multicolour light curves of 10 contact binary systems: V376 And, V523 Cas, CC Com, BX Dra, FG Hya, UZ Leo, XY Leo, AM Leo, EX Leo and RT LMi. The solutions resulted in a contact configuration for all systems. We found only FG Hya and UZ Leo to be in deep contact, the latter almost filling the outer critical lobe. The absolute parameters of the components have been determined with an accuracy of about a few per cent based on combined photometric and radial velocity curves, enlarging the sample of systems to 58 for which the physical parameters have been obtained in a uniform way. All but three systems (BX Dra, AM Leo and RT LMi) show asymmetries and peculiarities in the observed light curves, interpreted as resulting from their magnetic activity.
    Full-text · Article · Aug 2010 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We constrain the distribution of calcium across the surface of the white dwarf star G29-38 by combining time series spectroscopy from Gemini-North with global time series photometry from the Whole Earth Telescope. G29-38 is actively accreting metals from a known debris disk. Since the metals sink significantly faster than they mix across the surface, any inhomogeneity in the accretion process will appear as an inhomogeneity of the metals on the surface of the star. We measure the flux amplitudes and the calcium equivalent width amplitudes for two large pulsations excited on G29-38 in 2008. The ratio of these amplitudes best fits a model for polar accretion of calcium and rules out equatorial accretion.
    Full-text · Article · Apr 2010 · The Astrophysical Journal

Publication Stats

332 Citations
141.65 Total Impact Points

Institutions

  • 2009-2013
    • Pedagogical University of Cracow
      Cracovia, Lesser Poland Voivodeship, Poland
  • 1980-2012
    • Jagiellonian University
      Cracovia, Lesser Poland Voivodeship, Poland
  • 2010
    • University of Washington Seattle
      • Department of Astronomy
      Seattle, WA, United States
  • 1994
    • Astronomical Observatory
      Warszawa, Masovian Voivodeship, Poland