Alexandru Dumitrescu

Recent spectral observations of V449 Aur

There are numerous nearby and relatively bright short period binary systems included as targets of astronomical satellite missions. Most of them are not studied spectroscopically and photometrically in detail. Results of such an object, V449 Aur, are presented. Observations were carried out in January 2008 at BNAO Rozhen.

Exoplanet transits: orbit and size estimations

The modern astrophysical techniques allowed the observation of the exoplanets transits. The high accuracy photometric and spectroscopic observations contributed to this. The observational data consist of the photometric light‐curve generated by the planet transit and the radial velocity curve of the central star. The interpretation of these curves makes possible the estimation of some properties as: mass ratio, separation, orbit inclination, radius of the central star. We present different interpretation methods depending on the available observational data.

First ground‐based observations of the eclipsing binary V449 Aur made at Bucharest Observatory

The binary system V449 Aur was observed in Bucharest Observatory using the 50‐cm telescope. The light‐curve and the preliminary elements are presented.

Hipparcos Data Analysis of the Eclipsing Binary II UMa

Two light curve solutions for the close eclipsing binary II UMa, using Hipparcos data, are presented. The analysis was made using the PHOEBE program. The first solution was derived adopting the spectroscopic value q = 0.172 while the presence of third light was considered too. The second solution is based on the mass ratio value q = 0.13, derived by a q‐search. It was found that II UMa is an A sub‐class W UMa‐type binary, and belongs to a class of systems with very low mass ratio that is expected to evolve in a single rapidly rotating star.

Fifty Years of Stellar Astrophysics, Extragalactic Astronomy and Cosmology in Bucharest Observatory

This is a short review of some of the main activities of the Bucharest Observatory along the past 50 years: stellar astrophysics, galactic and extragalactic astrophysics and cosmology.