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A Study of the Hα Variability of Be Stars
Kjurkchieva, Diana P.; Dimitrov, Dinko P.; Ivanov, Emil I.
This paper presents the results of 4 years of high-resolution spectral observations of 69 emission-line stars, 54 of them being newly discovered sources. We classified the stars on the basis of their position in the two-color IR diagram and some additional criteria: shape and width of the Hα profile, presence of He lines, proper motion and paralla…
On the age of the Nele asteroid family
Vokrouhlický, D.; Nesvorný, D.; Carruba, V. +1 more
The Nele group, formerly known as the Iannini family, is one of the youngest asteroid families in the main belt. Previously, it has been noted that the pericentre longitudes ϖ and nodal longitudes Ω of its largest member asteroids are clustered at the present time, therefore suggesting that the collisional break-up of parent body must have happene…
Time assignment system and its performance aboard the Hitomi satellite
Dotani, Tadayasu; Kokubun, Motohide; Takahashi, Tadayuki +24 more
Fast timing capability in x-ray observation of astrophysical objects is one of the key properties for the ASTRO-H (Hitomi) mission. Absolute timing accuracies of 350 or 35 µs are required to achieve nominal scientific goals or to study fast variabilities of specific sources. The satellite carries a GPS receiver to obtain accurate time inform…
Magnetic Field Uniformity Across the GF 9-2 YSO, L1082C Dense Core, and GF 9 Filamentary Dark Cloud
Pillai, T.; Cerny, C.; Clemens, Dan P. +3 more
The orientation of the magnetic field (B field) in the filamentary dark cloud GF 9 was traced from the periphery of the cloud into the L1082C dense core that contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2 (IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission polarimetry (TEP) at 216 µm in c…
The JCMT Gould Belt Survey: A First Look at the Auriga-California Molecular Cloud with SCUBA-2
White, G. J.; Wilson, C. D.; Di Francesco, J. +57 more
We present 850 and 450 µm observations of the dense regions within the Auriga-California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular…
Disturbed Fossil Group Galaxy NGC 1132
Trinchieri, Ginevra; Fabbiano, Giuseppina; O'Sullivan, Ewan +10 more
We have analyzed the Chandra archival data of NGC 1132, a well-known fossil group, i.e., a system expected to be old and relaxed long after the giant elliptical galaxy assembly. Instead, the Chandra data reveal that the hot gas morphology is disturbed and asymmetrical, with a cold front following a possible bow shock. We discuss possible origins o…
Relativistic Astronomy
Zhang, Bing; Li, Kunyang
The “Breakthrough Starshot” aims at sending near-speed-of-light cameras to nearby stellar systems in the future. Due to the relativistic effects, a transrelativistic camera naturally serves as a spectrograph, a lens, and a wide-field camera. We demonstrate this through a simulation of the optical-band image of the nearby galaxy M51 in the rest fra…
High amplitude δ Scuti star BO Lyn with evidence of a late A-type companion in an elliptical orbit
Li, Lin-Jia; Qian, Sheng-Bang; Zhu, Li-Ying +2 more
We present 145 times of light maximum for high amplitude δ Scuti star BO Lyn based on several sky surveys (CRTS, DASCH, NSVS, OMC and SuperWASP) and our photometric observations. Combining with the data in literature, a total of 179 times of light maximum are used to analyze the O - C diagram of BO Lyn. We find that it can be described by an upwar…
Physical parameters and ±0.2% parallax of the detached eclipsing binary V923 Scorpii
Kervella, P.; Mérand, A.; Rucinski, S. M. +10 more
Context. V923 Sco is a bright (V = 5.91), nearby (π = 15.46 ± 0.40 mas) southern eclipsing binary. Because both components are slow rotators, the minimum masses of the components are known with 0.2% precision from spectroscopy. The system seems ideal for very precise mass, radius, and luminosity determinations and, owing to its proximity and long …
Identification and analysis of the young population in the starburst galaxy NGC 253
Baume, G.; Rodríguez, M. J.; Feinstein, C.
We present a study of the young population in the starburst galaxy NGC 253. In particular, we focused our attention on searching for young star groups, obtaining their main properties and studying their hierarchical organization. For this task, we used multiband images and their corresponding photometric data obtained with the Advanced Camera for …