A. V. Devyatkin

A concept of a space hazard counteraction system: Astronomical aspects

The basic science of astronomy and, primarily, its branch responsible for studying the Solar System, face the most important practical task posed by nature and the development of human civilization—to study space hazards and to seek methods of counteracting them. In pursuance of the joint Resolution of the Federal Space Agency (Roscosmos) and the RAS (Russian Academy of Sciences) Space Council of June 23, 2010, the RAS Institute of Astronomy in collaboration with other scientific and industrial organizations prepared a draft concept of the federal-level program targeted at creating a system of space hazard detection and counteraction. The main ideas and astronomical content of the concept are considered in this article.

Observations of extrasolar planet transits with the automated telescopes of the Pulkovo Astronomical Observatory

Exoplanet observations have been performed on the automated Pulkovo Observatory telescopes. We have obtained 33 transit light curves for 16 known exoplanets and six transit observations for three exoplanet candidates discovered by the Kepler telescope. Based on our observations, we have reliably confirmed the existence of an exoplanet with an extremely large radius, Rpl = 1.83 ± 0.16RJup, in the system KOI 256 and detected a strong deviation of its orbital revolution from the theoretically predicted one. During the transit of the exoplanet WASP-12b across the stellar disk, we detected bursts that could be caused by the planet transit across spots on the star or by the presence of a satellite around this exoplanet. We detected possible periodic variations in the duration of the exoplanet transit across the stellar disk with time for HAT-P-12b that could be caused by variations in orbital inclination. The transit duration and depth, the central transit time, and the radius and orbital inclination of the planet have been estimated. The equilibrium temperature and albedo have been estimated for several exoplanets.

Photometric Observations of Mutual Events in Saturn’s System of Regular Satellites in 1995

We carried out observations of mutual events in Saturn’s system of satellites as part of the PHESAT95 International Program. Three light curves of these events were obtained. We developed a technique of allowance for the influence of the law of light reflection from the surfaces of Saturn’s satellites, photometric nonuniformity of their surfaces, the phase effect, and the illumination distribution in the satellite penumbra (given the brightness distribution over the solar disk) on the light curve of an occultation or eclipse of one satellite by another. This technique is used to interpret our observations of these events and to determine the minimum separations between satellites or between a satellite and the shadow center of another satellite and the corresponding timings.

On chromatic effects in observations of the Sun near the horizon

The observability of the “green flash” in observations of the Sun near the horizon was calculated. The calculations were conducted with consideration for chromatic refraction, atmosphere transmission, spectral sensitivity of the eye, and image blurring due to the instability and inhomogeneity of the atmosphere.

Astrometric and photometric studies of the 2009 WZ104 asteroid as it approached the earth

The astrometric and photometric observations of the potentially hazardous 2009 WZ104 asteroid were carried out at the MTM-500M and ZA-320M automatic telescopes of the Pulkovo Observatory in December 2009. A total of 686 observations were performed in the integral band and 146 observations with B, V, R, and I filters on an arc of the orbit of 17°; these accounted for about 77% of all worldwide observations (http://www.minorplanetcenter.org/iau/ECS/MPCOBS/MPCOBS.html). On the basis of the obtained data, the orbit was improved and an estimation of the physical parameters of the asteroid was made. Estimates of the absolute stellar magnitude of the asteroid, H = (20.52 ± 0.04)m, as well as its size and mass, were obtained. The taxonomic class of the 2009 WZ104 asteroid (R or Q) was determined. A frequency analysis of the series of observations was carried out; periodicities in the asteroid’s light variation were revealed using this method.

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.

On the concept of the russian information and analytical center for asteroid and comet hazards

The concept is presented of the Russian information and analytical center for asteroid and comet hazards (IAC ACH) as a part of the national IAC for space threats. An overview is given of the center’s goals and objectives, as well as the requirements for the center, its structure, and the possible cooperation between the institutes of the Russian Academy of Sciences and other organizations in the creation of the center.

Astrometry and photometry of asteroid (308635) 2005 YU55

Astrometric and photometric observations of asteroid (308635) 2005 YU55 were carried out at the computer-aided ZA-320M and MTM-500M telescopes of the Pulkovo observatory in the period of its closest approach to the Earth, from November 9 to 20, 2011. The new orbit of the asteroid changed after its close approach to the Earth was determined. From this orbit, a close approach to Venus on January 19, 2029, was precalculated, and the distance at the closest approach—359000 km—was estimated. From the analysis of the acquired photometric data, the axial rotation period of the asteroid was more accurately determined, and it amounted to 16.3 ± 0.4 h. The color indexes of the asteroid, B-V, V-R, and R-I, were estimated, which allowed the taxonomic class of the asteroid, B, to be determined from them. In addition, from our photometric observations of the asteroid, the earlier unknown change in its brightness with a period of 0.9–1.2 h was detected; the cause of this change has not been completely studied yet.

Near Earth Objects Research in Pulkovo Observatory

More than 20000 observations of Near Earth asteroids and comets are collected and reduced in Pulkovo Observatory during last 10 years. For observations of these objects two robotic telescopes are used – ZA-320M (Cassegrain system, D = 320 mm, F = 3200 mm) at Pulkovo and MTM-500M (Maksutov – Cassegrain system, D = 500 mm, F = 4100 mm) at Kislovodsk mountain station. These telescopes perform CCD observations of objects up to 18.0 and 20.5 magnitude, correspondingly. The results of observations are regularly submitted to Minor Planet Center.