Positions of Mars obtained in Nikolaev Astronomical Observatory
Short Name:
Mars_pos
Date:
05 Dec 2018 17:51:36
Publisher:
Nikolaev Astronomical Observatory
Description:
Observations of Mars were carried out with the Zonal Astrograph at Nikolaev Astronomical Observatory. The mean period of observations in opposition was 156 days. The orbits of Mars and Earth were covered 7.3 and 3.8 times respectively. After defining more exactly some computational elements and the planet's phase, 441 positions were obtained in ICRS system. Coordinates of reference stars were taken from Hipparcos and Tycho catalogues, and their proper motions were taken from the ACTRC catalogue. The standard errors in right ascension and declination are ±0."21 and ±0."22 respectively, in accordance with accuracy estimations of the Institute of Applied Astronomy of the Russian Academy of Science. These standard errors are the best among all known photographic observations of Mars. Topocentric right ascension, declination in ICRS system (J2000.0), and Julian Days (UTC) are given in the table.
Most Sun-like stars in the Galaxy reside in gravitationally bound pairs of stars (binaries). Although long anticipated the existence of a 'circumbinary planet' orbiting such a pair of normal stars was not definitively established until the discovery of the planet transiting (that is, passing in front of) Kepler-16. Questions remained, however, about the prevalence of circumbinary planets and their range of orbital and physical properties. Here we report two additional transiting circumbinary planets: Kepler-34(AB)b and Kepler-35(AB)b, referred to here as Kepler-34b and Kepler-35b, respectively. Each is a low-density gas-giant planet on an orbit closely aligned with that of its parent stars. Kepler-34b orbits two Sun-like stars every 289 days, whereas Kepler-35b orbits a pair of smaller stars (89% and 81% of the Sun's mass) every 131 days. The planets experience large multi-periodic variations in incident stellar radiation arising from the orbital motion of the stars. The observed rate of circumbinary planets in our sample implies that more than ∼1% of close binary stars have giant planets in nearly coplanar orbits, yielding a Galactic population of at least several million.
The Space Telescope Imaging Spectrograph (STIS) was installed in HST on Feb. 14, 1997, replacing the GHRS spectrograph. STIS provides spectra and images at ultraviolet and visible wavelengths, probing the Universe from our solar system out to cosmological distances.
The abundance of heavy elements (metallicity) in the photospheres of stars similar to the Sun provides a "fossil" record of the chemical composition of the initial protoplanetary disk. Metal-rich stars are much more likely to harbour gas giant planets, supporting the model that planets form by accumulation of dust and ice particles5. Recent ground-based surveys suggest that this correlation is weakened for Neptunian-sized planets. However, how the relationship between size and metallicity extends into the regime of terrestrial-sized exoplanets is unknown. Here we report spectroscopic metallicities of the host stars of 226 small exoplanet candidates discovered by NASA's Kepler mission, including objects that are comparable in size to the terrestrial planets in the Solar System.
The WFPC2 is used to obtain high resolution images of astronomical objects over a relatively wide field of view and a broad range of wavelengths (1150 to 11,000 Å).
The WF/PC-1 was used from April 1990 to November 1993, to obtain high resolution images of astronomical objects over a relatively wide field of view and a broad range of wavelengths (1150 to 11,000 Angstroms).
