D. L. Gorshanov

Apex I and Apex II software packages for the reduction of astronomical CCD observations

We describe in detail the Apex I and Apex II software packages created for astrometric and photometric reductions of astronomical observations with CCD cameras. The Apex I software package has been created for the semiautomatic reduction of astronomical observations and has a convenient user interface. The Apex II software package allows for the completely automatic reduction of astrometric and photometric observations to be performed.

Observations and Theoretical Analysis of Lightcurves of Natural Satellites of Planets

We present the results of photometric observations of Saturns seventh satellite Hyperion and four other planetary satellites: Saturns moon Phoebe and three Jovian satellites Himalia, Elara, and Pasiphae. The observations have been conducted from September, 1999 to March, 2000, and during September–October, 2000. Analysis of periodic variations in Hyperions lightcurve was performed. The lightcurve was modeled using the software package developed for calculating the rotational dynamics of a satellite. Our data generally indicate that over the period of observations Hyperion was in the chaotic mode of rotation.

Astrometric results of observations at russian observatories of mutual occultations and eclipses of Jupiter’s Galilean satellites in 2009

In 2009, in five Russian observatories photometric observations of Jupiter’s Galilean satellites during their mutual occultations and eclipses were carried out. Based on these observations, an original method was used to ascertain astrometric results such as the difference between the coordinates of pairs of satellites. Fifty-three phenomena were successfully observed. A total of 94 light curves of satellites were measured. The error in the coordinates of satellites due to random errors in photometry, calculated on all data obtained, was 0.041″ in right ascension and 0.046″ in declination. The discrepancies between the theory and observations in these coordinates was found to be 0.060″ and 0.057″, respectively. The results were uploaded to the common database for all observations of natural satellites of planets at the Natural Satellites Data Center (NSDC), which is available online at http://www.sai.msu.ru/neb/nss/index.htm. For the first time in the practice of photometric observations of satellites in epochs of mutual occultations and eclipses a new method of observation was tested, which eliminates from astrometric results the major systematic errors caused by an inaccurate account of the background level. The tests were conducted in the Terskol Observatory and the observatory of the Crimean laboratory of the Sternberg State Astronomical Institute of the Moscow State University. The application of the new method showed that the elimination of the background level at these observatories was carried out correctly.

Astrometric and photometric observations of solar system bodies with Pulkovo Observatory’s automatic mirror astrograph ZA-320M

A brief description of the process of astrometric and photometric observations and their processing by an automatic complex, based on Pulkovo Observatory’s ZA-320M telescope, is presented. The basic results of astrometric and photometric observations of Solar System bodies obtained during 1997–2007 are given. They include, in particular, the results of astrometric observations of dangerous objects ( Near Earth Objects — NEOs), as well as the results of astrometric observations of the Pluto-Charon system. In addition, the paper presents the results of photometric observations of planetary satellites, the mutual phenomena in the system of Jupiter’s satellites, and the 2559 star occultation by the (111) Ate asteroid from the HIPPARCOS catalogue.

Some specific features of light curves of (39) Laetitia, (87) Sylvia, (90) Antiopa, and 2006 VV2 asteroids

The results of photometric observations of (87) Sylvia, 2006 VV2, (90) Antiopa, and (39) Laetitia asteroids in 2006–2008 are presented. The specific features of light curves are considered for each object. In particular, for asteroid (87) Sylvia, possible mutual phenomena in this triple system are identified. Asteroid 2006 VV2 manifests a strong dependence of the light curve on the filter color, which testifies to the presence of inhomogeneities on its surface. The previously unknown brightness variation period with a duration of about three days was obtained for this asteroid. For binary asteroid (90) Antiopa, the strong dependence of its brightness on the phase angle was noticed; this may testify to the very flattened shape of its components. Considerable time variations of the shape of the light curve for asteroid (39) Laetitia may testify either to its complex shape or to its binary character.

The observations of Near Earth Objects by the automatic mirror astrograph ZA–320M at Pulkovo observatory

At Pulkovo Observatory, we conduct observations of various Solar System bodies: major planets, their satellites, comets, and asteroids, including Near Earth Objects. For these purposes, a robotic telescope was constructed on the base of the ZA–320 Mirror Astrograph ( D =320 mm, F =3200 mm). It can perform CCD observations of Solar System bodies with the limiting magnitude of up to 19.0. Independent ephemeris support is provided by the EPOS software package developed at Pulkovo Observatory; it includes tracing of catalogues of comets and asteroids, regular ephemeris calculations, and control of observations. CCD frame processing is done by the Apex automatic data reduction package developed at Pulkovo Observatory. In 2001-2006, more than 12000 observations of minor Solar System bodies were collected, including more than 6000 positions of 656 NEAs, about 1200 observations of 27 comets, and about 2000 observations of major planets satellites. The mean accuracy of obtained positions is 0″.09−0″.40. Results of observations are regularly submitted to the Minor Planet Center. Currently, ZA–320M is the 16-th of more than 680 telescopes in the worldwide rating of those that observe NEAs (by the number of observations). In the near future, our group is planning to start observations with another two robotic telescopes: MTM–500 ( D =500 mm, F =4000 mm Maksutov) and 1-meter telescope ( D =1000 mm, F =1200 mm) of the Pulkovo mountain station at Northern Caucasus (Kislovodsk, 2100 m above sea level). These two instruments will allow to increase the number of observations, their accuracy, and limiting magnitude (up to 20.5 mag).

Observations of asteroids in the infrared range (JHK) at the AZT-24 telescope

In 2007–2010, ten asteroids were observed in the JHK bands. The color indexes J-H and H-K were determined from the observations. Their positions in the two-color diagram generally correspond to the areas occupied by the asteroids of the corresponding taxonomic types. For two asteroids, (624) Hektor and (762) Pulcova, the light curves in the J and H bands and the curves of the color index J-H were constructed. The changes in the color index J-H from 0.05m to 0.1m were revealed; it may be supposed that they are caused by the heterogeneity in structure or mineral composition of the surface. For all of the asteroids, the astrometric positions were obtained. It was found that the best reference catalogue for the astrometric processing of observations of asteroids in the JHK bands under a small field of view is the 2MASS survey.

Estimates of dynamic parameters and boundaries of habitable zones of selected stars of the Pulkovo program

A list of selected binary stars is presented that have been observed for several decades using a 26-inch refractor at the Pulkovo Observatory. These stars are at a distance from 3.5 to 25 pc from the Sun. They belong to spectral classes F, G, K, and M. Their masses range from 0.3 to 1.5 solar masses. We have analyzed them as possible parent stars for exoplanets taking into account the physical characteristics of these stars. In view of dynamic parameters and orbital elements that we have obtained by Pulkovo observations, ephemerides of positions for the coming years are calculated. The boundaries of the habitable zones around these stars are calculated. The astrometric signal that depends on the gravitational influence of hypothetical planets is estimated. Space telescopes for astrometric observations with microsecond accuracy can be used to detect Earth-like planets near the closest stars of this program. This paper presents an overview of astrometric programs of searches for exoplanets.

Astrometric baseline observations of solar system bodies

The use of ground-based and space baseline observations of Solar System bodies is considered. Baseline observations allow one to determine the distance to observed objects and (in some cases) the parameters of their orbital motion. Certain results of baseline observations of near-Earth asteroids and the results of model analysis of spacecraft observations are presented.

Astrometric and photometric investigation of asteroids (3100) Zimmerman, (3504) Kholshevnikov, (4592) Alkissia, (4619) Polyakhova

Observations of the chosen understudied asteroids of the main belt, named after astronomers of Pulkovo observatory and St.Petersburg State University (3100) Zimmerman, (3504) Kholshevnikov, (4592) Alkissia, (4619) Polyakhova were made. The data was processed and light curves of the asteroids were obtained. Axial rotation periods of the observed objects were discovered for the first time. Accuracy of the orbital elements of the asteroids was estimated on the basis of obtained observations and MPC data.