Search Publications
Identification and period investigation of pulsation variable star UY Camelopardalis, an RR Lyrae star in binary system
Li, Lin-Jia; Qian, Sheng-Bang; Voloshina, Irina +3 more
We present photometric measurements of the short period variable star UY Cam, which has been classified as a δ Scuti or c-type RR Lyrae (RRc) variable in different catalogs. Based on the analyses on Fourier coefficients and (NUV - V)0, we find that UY Cam is probably an RRc star. We obtain 58 new times of light maximum for UY Cam based …
A New Method to Comprehensively Diagnose Shock Waves in the Solar Atmosphere Based on Simultaneous Spectroscopic and Imaging Observations
He, Jiansen; Wang, Linghua; Yan, Limei +3 more
Shock waves are believed to play an important role in plasma heating. The shock-like temporal jumps in radiation intensity and Doppler shift have been identified in the solar atmosphere. However, a quantitative diagnosis of the shocks in the solar atmosphere is still lacking, seriously hindering the understanding of shock dissipative heating of th…
Thermal Emission in the Quiescent Neutron Star SAX J1810.8-2609
Allen, Jessamyn L.; Homan, Jeroen; Chakrabarty, Deepto +1 more
We have observed the neutron star low-mass X-ray binary SAX J1810.8-2609 in quiescence with XMM-Newton. SAX J1810.8-2609 is one of the faintest non-pulsing neutron star low-mass X-ray binaries in quiescence and previously only had upper limits on its quiescent thermal emission. We found SAX J1810.8-2609 at the same 0.5-10 keV, unabsorbed luminosit…
The Three-dimensional Orbit, Orbital Parallax, and Individual Masses of the Double-lined Spectroscopic Binaries HD 183255, HD 114882, and HD 30712
Docobo, J. A.; Horch, Elliott P.; Campo, P. P. +1 more
Recent speckle observations performed at the Discovery Channel Telescope, the Gemini North Telescope, and the Special Astrophysical Observatory 6 m Telescope have permitted us to calculate the visual orbit of SB2 HD 114882 for the first time and to improve the visual orbits of two other SB2 systems, HD 30712 and HD 183255, using algorithms publish…
Kinematics and Dynamics of the Galactic Halo from RR Lyrae Variable Stars
Dambis, A. K.; Zhao, G.; Rastorguev, A. S. +3 more
Based on a sample of RR Lyrae variable stars including more than 9000 objects with proper motions and distances, we have investigated the kinematics of the Galactic halo from the two-dimensional velocity field. We have used both the proper motions deduced independently by us from the positional data taken from all-sky catalogues in a time interval…
Pulsation in Intermediate-Mass Stars
Balona, Luis A.
A new perspective of pulsation in stars within the δ Scuti instability strip has recently emerged as a result of Kepler observations. The majority of stars within the instability strip do not pulsate and practically all δ Scuti stars contain low frequencies. Because γ Doradus stars co-exist with δ Sct stars in the same region of the instability st…
The role of molecular gas in the nuclear regions of IRAS 00183-7111. ALMA and X-ray investigations of an ultraluminous infrared galaxy
Vignali, C.; Iwasawa, K.; Paladino, R. +2 more
Aims: We present a multi-frequency study of the ultraluminous infrared galaxy (ULIRG) IRAS 00183-7111 (z = 0.327), selected from the Spoon diagnostic diagram as a highly obscured active galactic nucleus (AGN) candidate. ALMA millimetre and X-ray observations are used; the main aim is to verify at what level the molecular gas, traced by the CO…
A correlation between GALEX FUV magnitude and chromospheric activity among red giant stars
Smith, Graeme H.
It is shown that upon combining GALEX far-ultraviolet and Johnson B magnitudes a resultant FUV-B colour can be obtained that for red giant stars of luminosity classes III and II correlates well with chromospheric emission in the cores of the Mg II h and k lines. Giant stars throughout the colour range 0.8 ≤ B - V ≤ 1.6 exhibit such a phenomenon. T…
New transient Galactic bulge intermediate polar candidate XMMU J175035.2-293557
Haberl, F.; Ponti, G.; Hofmann, F. +1 more
Context. For the past decades, a rare subclass of cataclysmic variables (CV), with magnetised white dwarfs (WD) as accretors, has been studied. They are called intermediate polars (IP) and have been suggested to be the main contributors to the diffuse, hard X-ray emission close to the Galactic center (GC) and in the Galactic bulge (GB), because mo…
Changes in the pulse phase dependence of X-ray emission lines in 4U 1626-67 with a torque reversal
Paul, Biswajit; Beri, Aru; Dewangan, Gulab C.
We report results from an observation with the XMM-Newton observatory of a unique X-ray pulsar 4U 1626-67. European Photon Imaging Camera-pn data during the current spin-up phase of 4U 1626-67 have been used to study pulse phase dependence of low-energy emission lines. We found strong variability of low-energy emission line at 0.915 keV with the p…