Search Publications
Comparison of Parallaxes from Eclipsing Binaries Method with Hipparcos Parallaxes
Semeniuk, Irena
The parallaxes determined by Lacy (1979) by means of eclipsing binaries method are compared with the Hipparcos parallaxes for 19 systems. The residual scatter of the distance moduli inferred from eclipsing binaries method - after allowing for known errors as given by Lacy and Hipparcos - is equal to 0.18 mag. It decreases to 0.08 mag when obviousl…
Empirical Luminosities and Radii of Early-Type Stars after Hipparcos
Jerzykiewicz, M.; Molenda-Zakowicz, J.
Using Hipparcos parallaxes we derive empirical luminosities and radii of the early-type stars for which the effective temperatures are known from directly measured angular diameters and total absolute fluxes. The empirical luminosities allow a direct comparison of the position of these stars in the fundamental HR diagram with evolutionary tracks. …
Fourier Analysis of Hipparcos Photometry of Cepheid Variables
Moskalik, P.; Ogloza, W.; Zakrzewski, B.
Fourier parameters have been computed for 240 field Cepheids observed by the Hipparcos satellite. We have identified three new PopulationI overtone Cepheids: V411Lac, V898 Cen and V572 Aql. We have compared Fourier progressions of Population I and Population II Cepheids. The possibility of using Fourier parameters to distinguish between the two ty…
Interstellar Carbon Abundance
Gnacinski, Piotr
We present 10 new measurements of carbon gas phase column density in the interstellar medium. We have used spectra made with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope containing the CII 1334.5 Ang and CII* 1335.7 Ang lines. The continuum reconstruction method has been used to obtain the carbon column density from t…
Nearby Hipparcos Eclipsing Binaries for Color-Surface Brightness Calibration
Kruszewski, A.; Semeniuk, I.
This paper contains the list of Hipparcos eclipsing binaries that fulfill the following conditions: the star is classified in the Hipparcos Catalogue as EA-type eclipsing binary and its parallax is either larger than 5 mas or it is five times larger than its mean error. An eclipsing binary with known distance and with photometric and double-line s…
The Optical Gravitational Lensing Experiment. UBVI Photometry of Stars in Baade's Window
Udalski, A.; Wozniak, P.; Kubiak, M. +5 more
We present UBVI photometry for 8530 stars in Baade's Window obtained during the OGLE-II microlensing survey. Among these are over one thousand red clump giants. 1391 of them have photometry with errors smaller than 0.04, 0.06, 0.12, and 0.20 mag in the I, V, B, and U-band, respectively. We constructed a map of interstellar reddening. The corrected…
The Optical Gravitational Lensing Experiment. The Distance Scale: Galactic Bulge -- LMC -- SMC.
Udalski, A.
We analyze the mean luminosity of three samples of field RRab Lyr stars observed in the course of the OGLE microlensing experiment: 73 stars from the Galactic bulge and 110 and 128 stars from selected fields in the LMC and SMC, respectively. The fields are the same as in the recent distance determination to the Magellanic Clouds with the red clump…
BVI CCD Photometry of the Globular Cluster 47Tuc
Stanek, K. Z.; Kaluzny, J.; Krzeminski, W. +1 more
We present BVI photometry for about 16000 stars from a 220 square arcmin field centered 8arcmin East of the center of 47 Tuc. We have identified eight likely blue stragglers located in the outer parts of the cluster. Four of these objects are easy targets for spectroscopic studies with ground-based telescopes. Six candidates for blue horizontal br…
Study of Neglected Variable Stars Classified as Type II Cepheids
Szabados, L.; Berdnikov, L. N.
Four variable stars classified as Type II Cepheids have been studied partly based on new photometry and the Hipparcos photometric data. The correct period is derived for V341 Ara and NW Pav and it is pointed out that RR Mic and V1711 Sgr do not belong to Type II Cepheids, instead they may be semi-regular variables. The cycle length of their variab…
Spectral Components in the Optical Emission of the Seyfert Galaxy NGC 5548 and the Comparison of Intrinsic Nuclear Spectra with Accreting Corona Model
Czerny, B.; Kuraszkiewicz, J.; Loska, Z.
We study the extensively monitored Seyfert galaxy NGC 5548 and compare its nuclear emission with models of accretion disk with accreting corona. To obtain the intrinsic nuclear spectra from the observed spectra we had to estimate and subtract the contribution from circumnuclear components such as stars, the Balmer continuum and blended FeII lines,…