相关论文: In-depth study of 16CygB using inversion technique…
Ambipolar diffusion is a physical mechanism related to the drift between charged and neutral particles in a partially ionized plasma that is key in many different astrophysical systems. However, understanding its effects is challenging due…
This paper describes the design principles for a CCD-based photometric system that is highly optimized for ground-based measurement of the size of the Balmer jump in stellar energy distributions. It is shown that, among ultraviolet filters…
Since it has become possible to discovery planets orbiting nearby solar-type stars through very precise Doppler-shift measurements, the role of methods used to analyze such observations has grown significantly. The widely employed…
Binary systems containing a massive star and a non-accreting pulsar present strong interaction between the stellar and the pulsar winds. The properties of this interaction, which largely determine the non-thermal radiation in these systems,…
In this paper, we present a semi-empirical model of isolated binary star formation. This model includes the effects of turbulence in the initial state of the gas, and has binary orbital parameters consistent with observation. Our…
KIC8264293 is a fast rotating B-type pulsator observed by Kepler satellite. Its photometric variability is mainly due to pulsations in high-order g modes. Besides, we detected a weak H$\alpha$ emission. Thus, the second source of…
The size of convective cores remains uncertain, despite its substantial influence on stellar evolution, and thus on stellar ages. The seismic modeling of young subgiants can be used to obtain indirect constraints on the core structure…
Observations of double-lined spectroscopic eclipsing binaries are ideal to study stellar evolution. They have tight model-independent constraints on their masses and radii. With the addition of spectroscopically determined effective…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
Using the Planetary Camera on board the Hubble Space Telescope we have measured the projected separation of the binary components in the nucleus of the planetary nebula Abell 35 to be larger than 0.08 arcsecs but less than 0.14 arcsecs. The…
Theories of stellar convective core overshoot can be examined through analysis of pulsating stars. Better accuracy can be achieved by obtaining external constraints such as those provided by observing pulsating stars in eclipsing binary…
I discuss the effect of physical distortion on the velocities of close binary components and how we may use the resulting distortion of velocity curves to constrain some properties of binary systems, such as inclination and mass ratio.…
We have undertaken a survey of H alpha emission in a substantially complete sample of CGCG galaxies of types Sa and later within 1.5 Abell radii of the centres of 8 low-redshift Abell clusters. Some 320 galaxies were surveyed, of which 116…
V1765 Cyg is a detached eclipsing binary containing a B0.5 supergiant and a B1 main-sequence star, with an orbital period of 13.37 d and an eccentricity of 0.315. The system shows apsidal motion and the supergiant exhibits strong stochastic…
Early-type B stars with strong magnetic fields and rapid rotation form centrifugal magnetospheres (CMs), as the relatively weak stellar wind becomes magnetically confined and centrifugally supported above the Kepler co-rotation radius. CM…
Several studies in the recent past have inferred the existence of thermal inversions in some transiting hot Jupiter atmospheres. Given the limited data available, the inference of a thermal inversion depends critically on the chemical…
The aim of this PhD Thesis is to characterize a representative sample of Supergiant X-ray Binaries (SGXBs) formed by 4 sources: XTE J1855-026, a classical SGXB with long-term stable X-ray flux; AX J1841.0-0535 and AX J1845.0-0433, two…
We present B and R band spectroastrometry of a sample of 45 Herbig Ae/Be stars in order to study their binary properties. All but one of the targets known to be binary systems with a separation of ~0.1-2.0 arcsec are detected by a…
Recent theoretical calculations of stellar evolutionary tracks for rotating high-mass stars suggests that the chemical composition of the surface layers changes even whilst the star is evolving on the Main Sequence. The abundance analysis…
As a part of our ongoing Volume-limited A-Star (VAST) adaptive optics survey, we have obtained observations of 26 binary systems with projected separations <100 AU, 13 of which have sufficient historical measurements to allow for refinement…