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The puzzling high velocity G5 supergiant star HD 179821: new insight from Gaia DR2 data
Jasniewicz, G.; Parthasarathy, M.; Thěvenin, F.
HD 179821 is classified as G5 Ia star. From the IRAS colors and spectral energy distributions it was classified as a post-AGB star. But some studies classify it as a massive (30 to
Millimeter and Far-IR Study of the IRDC SDC 341.232-0.268
Rubio, M.; Firpo, V.; Cappa, C. E. +3 more
We analyze the molecular gas and dust associated with the infrared dark cloud SDC 341.232-0.268 in order to investigate the characteristics and parameters of the gas, determine the evolutionary status of four embedded EGO candidates, and establish possible infall or outflow gas motions. We base our study on 12CO(2-1), 13CO(2-…
On the weak Lyα emission line of BL Lacertae objects
Bu, Jia; Ma, Ren-Yi; Fang, Tao-Tao +2 more
Recent studies reveal that weak Lyα emission line may be a ubiquitous feature of nearby BL Laceratae objects (BL Lacs). We present a survey of the Lyα emission lines in BL Lacs, with a focus on data obtained by the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. Among the 11 selected targets, seven show a clear detection of the int…
The dynamics of the outer edge of Saturn's A ring perturbed by the satellites Janus and Epimetheus
Cooper, N. J.; Murray, C. D.; El Moutamid, M. +4 more
We present an analytical model to study the dynamics of the outer edge of Saturn's A ring. The latter is influenced by 7:6 mean motion resonances with Janus and Epimetheus. Because of the horseshoe motion of the two co-orbital moons, the ring edge particles are alternately trapped in a corotation eccentricity resonance (CER) or a Lindblad eccentri…
A multi-molecular line study of the star-forming globule CB88-230
Codella, C.; Giannetti, A.; Massi, F. +2 more
Context. This paper relates to low-mass star formation in globules, and the interaction of newly-formed stars with their environment. We follow up on the results of our earlier observations of this globule.
Aims: Our aim is to study the gas- and dust environment of the young stellar object (YSO) in globule CB88 230, the large-scale molecular …
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…