Search Publications
Analytical Resolution of the Dark Night Sky (Olbers') Paradox
Harari, Zaki
We derive a spatiotemporal analytical resolution of the dark night sky, or Olbers' paradox, first showing that in an infinitely large universe the cumulative solid angle of the light that is projected upon the celestial sphere by an infinite population of directly observable stars is indeed finite. Using the GAIA DR2 data, we show that the number …
ExoMars Schiaparelli Direct-to-Earth Observation using GMRT
Asmar, S. W.; De, K.; Gupta, Y. +3 more
During the ExoMars Schiaparelli separation event on 16 October 2016 and Entry, Descent, and Landing (EDL) events 3 days later, the Giant Metrewave Radio Telescope (GMRT) near Pune, India, was used to directly observe UHF transmissions from the Schiaparelli lander as they arrive at Earth. The Doppler shift of the carrier frequency was measured and …
Gaia DR2 and the Virtual Observatory: VO in Operations New Era
Merín, Bruno; Hambly, Nigel C.; Allen, Mark +15 more
During the last decade, the IVOA (International Virtual Observatory Alliance) has been tasked with the difficult task of defining standards to interchange astronomical data. These efforts have been supported by many IVOA partners in general and by the ESAC Science Data Centre (ESDC) in particular, that have been collaborating in the definition of …
A Detailed Investigation on the Infrared-excess Binary EG Cassiopeiae
Yang, Yuangui; Yuan, Huiyu; Dai, Haifeng
In this study, new data concerning the EB-type eclipsing binary EG Cas are presented as observed using three telescopes in China. A spectral type of F0V was determined from the low-precision spectrum. By solving the radial velocity and BV light curves, the absolute parameters of this system are preliminarily deduced. The results imply that EG Cas …
New outburst from the luminous supersoft source SSS1 in NGC 300 with periodic modulation
Haberl, F.; Maitra, C.; Carpano, S.
The nearby galaxy NGC 300 is hosting two luminous transient supersoft X-ray sources with bolometric luminosities above 3 × 1038 erg s-1, assuming simple blackbody spectra with temperatures around 60-70 eV. For one of these, SSS1, a periodic modulation of 5.4 h was observed in an XMM-Newton observation from 2001 Jan…
Neutral-gas-phase metal abundances in Zn II-selected quasar absorption line systems near redshift z = 1.2
Turnshek, David A.; Rao, Sandhya M.; Monier, Eric M. +2 more
We present 10 metallicity measurements for quasar absorbers near z = 1.2 that were selected for having unusually significant Zn II absorption in their Sloan Digital Sky Survey (SDSS) spectra. Follow-up UV space spectroscopy of the Lyα region shows that all 10 have damped Lyα (DLA) absorption, corresponding to neutral hydrogen column densities in t…
Flares activity of selected stars from GTSh10 catalog by CRTS data
Gorbachev, M. A.; Shlyapnikov, A. A.
Based on the database of photometric observations of the CRTS project over an interval of more than 9 years, the activity of red dwarfs from the GTSh10 catalog was analyzed. The total number of analyzed objects, a list ares, amplitudes and moments of recorded events are presented. For the most interesting objects, from the point of view are activi…
SB 796: a high-velocity RRc star
Soszyński, Igor; Gomel, Roy; Faigler, Simchon +6 more
We report here on a detailed study of a c-type RR Lyrae variable (RRc variable), SB 796, serendipitously discovered in a search of the WASP public data for stars that display large photometric periodic modulation. SB 796 displays a period of P = 0.26585 d and semi-amplitude of ∼0.1 mag. Comparison of the modulation shape and period with the detail…
Long-Term Activity of a Little Known Dwarf Nova DT Octantis
Šimon, V.; Edelmann, H.
We analyze the long-term activity of a little known dwarf nova (DN) DT Oct. We use photographic observations from the Bamberg Observatory (Southern Patrol Photographic Sky Survey), CCD data from ASAS-3 survey, and AAVSO data (both CCD and visual). We determined the recurrence times of the superoutbursts, TCso, and of the normal outburst…
A new binary star system of EA type in Perseus: UCAC4 735-019611
Brincat, S. M.; Galdies, C.; Grech, W.
Discovery of a new binary star system (UCAC4 735-019611=USNO-B1.0 1469-0068570=2MASS J01561032+5657563) in the Perseus constellation is presented. It was discovered during asteroid photometric work. The shape of the light curve and its characteristics (period of 2.12701±0.00001d, amplitude of V=0.55 mag, initial minimum period epoch HJD 2457363.37…