Search Publications
On a New Technique for Discovering Variable Stars
Mironov, A. V.; Zakharov, A. I.; Nikolaev, F. N.
A technique for discovering variable stars based on the calculation of the correlation coefficients is proposed. Applications of the technique are shown on the results of numerical experiments and on the Hipparcos photometric data.
High Precision with the Whole Earth Telescope: Lessons and Some Results from XCov20 for the roAp Star HR 1217
Kepler, S. O.; Kawaler, S. D.; Winget, D. E. +41 more
HR 1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of nonradial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 mu Hz and 34.6 mu Hz, with a sixth mode at a problematic spacing of 50.0 mu Hz (which equals 1.5 times 33.3 mu Hz) to the h…
Calibration of the Strömvil Photometric System
Sperauskas, J.; Straižys, V.; Boyle, R. P. +4 more
A calibration of color indices of the Strömvil photometric system in terms of physical parameters of stars is presented. The calibration is based on photoelectric photometry of about 1000 stars with known effective temperatures, distances, gravities and metallicities. The observations were accomplished in 2000--2003 with the 1.5 meter telescope of…
Classification of Metal-Deficient Dwarfs in the Vilnius Photometric System
Bartkevičius, A.; Bartašiūtė, S.; Lazauskaitė, R.
Methods used for the quantitative classification of metal-deficient stars in the Vilnius photometric system are reviewed. We present a new calibration of absolute magnitudes for dwarfs and subdwarfs, based on Hipparcos parallaxes. The new classification scheme is applied to a sample of Population II visual binaries.
Kinematics of Hipparcos Visual Binaries. II. Stars with Ground-Based Orbital Solutions
Bartkevičius, A.; Gudas, A.
This paper continues kinematical investigations of the Hipparcos visual binaries with known orbits. A sample, consisting of 804 binary systems with orbital elements determined from ground-based observations, is selected. The mean relative error of their parallaxes is about 12% and the mean relative error of proper motions is about 4%. However, eve…
Interstellar Extinction Along the Camelopardalis and Perseus Border
Zdanavičius, J.; Zdanavičius, K.
Interstellar extinction in a ~ 100 sq. degree area at the Camelopardalis and Perseus border is investigated. The study is based on the results of photoelectric photometry of 455 stars in the seven-color Vilnius photometric system published earlier. The nearest 100 stars with Hipparcos parallaxes show that the extinction starts to grow at a distanc…
Kinematics of Hipparcos Visual Binaries. I. Stars with Orbital Solutions
Bartkevicius, A.; Gudas, A.
A sample consisting of 570 binary systems is compiled from several sources of visual binary stars with well-known orbital elements. High-precision trigonometric parallaxes (mean relative error about 5%) and proper motions (mean relative error about 3%) are extracted from the Hipparcos Catalogue or from the reprocessed Hipparcos data. However, 13% …
Stars with the Largest Hipparcos Photometric Amplitudes
Adelman, Saul J.
A list of the 2027 stars that have the largest photometric amplitudes in Hipparcos Photometry shows that most variable stars are all Miras. The percentage of variable types change as a function of amplitude. This compilation should also be of value to photometrists looking for relatively unstudied, but large amplitude stars.
Surface Photometry of Spiral Galaxies at Redshifts 0.15 to 1
Tamm, A.; Tenjes, P.
Using HST archive observations for three disk galaxies at redshifts z = 0.15, 0.90 and 0.99, and the astronomical data processing system IRAF/STSDAS, we derived their surface brightness profiles. Derived luminosity distributions were reduced to standard V and I magnitudes. After corrections for cosmological distortion (k-correction), the surface b…
On the Photometric Variability of Red Clump Giants
Adelman, Saul J.
Hipparcos photometry of the 308 red clump giants identified by Paczynski et al. (1999) is investigated. These stars are found to be quite stable during the three years of observation, but questions remain about longer term stability.