共查询到20条相似文献，搜索用时 31 毫秒
1.
The discovery of binaries among the population of transneptunian objects isa landmark advance in the study of this remote region of the solar system.Determination of binary orbits will enable direct determination of systemmasses, fundamental for determination of density, internal structure, and bulkcomposition. The mere existence of binaries with the observed separations andapparent masses constrains models of planetary formation. 相似文献
2.
A.F.J. Moffat 《Astrophysics and Space Science》1998,260(1-2):225-242
Colliding winds in binaries are discussed mainly from an observational point of view. Collisions are especially energetic
in the case of hot, luminous stars, which drive strong, fast winds. Emphasis is therefore devoted to binaries containing Wolf-Rayet
stars. The subject is divided up into (1) continuum radiation (X-ray and non-thermal radio from the hot bow shock head, IR
from dust formed in some WC + O binaries far downstream in the collision shock cone) and (2) line radiation (optical and UV,
both from various regions downstream from the bow shock head). The latter is particularly useful in providing constraints
on the velocity field and hence ultimately the geometry of the wind collision and the binary system itself.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Photometric solutions of four new discovered W UMa-type binaries were carried out for the first time by using the 2003 version
of the W-D program. It is discovered that all of the four systems are over-contact binaries. Two binaries, GSC 0804-0118 and
GSC 2936-0478, are of A-subtype, while two other binaries, GSC 1848-1264 and GSC 0619-0232, are of W-subtype. From our solutions,
the fundamental orbital and physical parameters were determined. For GSC 0619-0232 and GSC 2936-0478, the asymmetries of the
light curves (i.e., the O'Connell effect) were explained by the presence of dark spots on the more massive components. Our
photometric results reveal that GSC 0619-0232 is an important and interesting system. It is a W-type over-contact binary with
a low mass ratio of q = 0.100 and a high over-contact degree of f = 93.4%, which suggests that GSC 0619-0232 may be evolved into a single rapid-rotating star. 相似文献
4.
张忠勇 《中国天文和天体物理学报》1993,(1)
本文首先介绍激变变星SU UMa型星的驼峰现象和最近发现的X射线新星中各类光变,再从理论上探讨这些光变与驼峰现象的关系,推测驼峰现象不仅出现于光学波段,而且可能出现于紫外和X射线波段.最后,建立一种由驼峰现象判断主星是否为黑洞的可能方法. 相似文献
5.
Pavel Koubský 《Astrophysics and Space Science》2005,296(1-4):165-168
A brief review of Be stars in binaries is presented. Attention is paid to systems, where the Be phenomenon is clearly connected
to the duplicity, but is not a simple consequence of mass transfer. 相似文献
6.
D. Koch W. Borucki G. Basri T. Brown D. Caldwell J. Christensen-Dalsgaard W. Cochran E. Dunham T. N. Gautier J. Geary R. Gilliland J. Jenkins Y. Kondo D. Latham J. Lissauer D. Monet 《Astrophysics and Space Science》2006,304(1-4):391-395
The Kepler Mission is a photometric space mission that will continuously observe a single 100 square degree field of view (FOV) of the sky of more than 100,000 stars in the Cygnus-Lyra region for four or more years with a precision of 14 parts per million (ppm) for a 6.5 hour integration including shot noise for a twelfth magnitude star. The primary goal of the mission is to detect Earth-size planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected. Prior to launch, the stellar characteristics will have been determined for all the stars in the FOV with K<14.5. As part of the verification process, stars with transits (about 5%) will need to have follow-up radial velocity observations performed to determine the component masses and thereby separate grazing eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for uses such as for EB modeling of the high-precision light curves. A guest observer program is also planned for objects not already on the target list. 相似文献
7.
陆文贤 《中国天文和天体物理学报》1988,(1)
使用像管摄谱仪和Reticon探测器获得了食双星AA UMa的高色散和高时间分辨率的光谱,并用交叉相关函数法测得其视向速度。从光谱特征来看,AA UMa是一对W UMa型食双星。本文首次给出了AA UMa的分光轨道解。在圆周运动的假设下,轨道根数测定为:P=0.468171天;T_0(相应于测光主极小时刻)=HJD2,446,520.4448;K_1=124.0公里/秒;K_2=227.7公里/秒。像其他一些使用本方法获得分光轨道解的食双星一样,AA UMa系统的质心速度没有能够唯一地确定,但是V_0=-34.8公里/秒可能是一个较好的估值。根据分光轨道根数,本文给出了新的测光历元公式:HJD Min I=2,446,520,4448(8)+0.468171(48)·E。AA UMa两子星的光谱型十分相似,与变星总表(GCVS)所列的GoV相一致。两子星的质量比为0.54,星等差为0.36(～B) 相似文献
8.
陆文贤 《中国天文和天体物理学报》1990,(3)
本文首次测定了WX Cnc的分光轨道解。轨道根数是:V_0=+9.8公里/秒;K_1=110.2公里/秒;K_2=149.0公里/秒;T_0=HJD 2,446,480.0309。结合文献中测光结果,得到了WX Cnc的绝对参量:A=6.32R_⊙;R_1=1.53R_⊙;R_2=1.18R_⊙ M_1=1.29M_⊙;M_2=0.96M_⊙。分光质比q=0.74。 相似文献
9.
10.
The study of detached eclipsing binaries in open clusters can provide stringent tests of theoretical stellar evolutionary models, which must simultaneously fit the masses, radii, and luminosities of the eclipsing stars and the radiative properties of every other star in the cluster. We review recent progress in such studies and discuss two unusually interesting objects currently under analysis. GV Carinae is an A0 m + A8 m binary in the Southern open cluster NGC 3532; its eclipse depths have changed by 0.1 mag between 1990 and 2001, suggesting that its orbit is being perturbed by a relatively close third body. DW Carinae is a high-mass unevolved B1 V + B1 V binary in the very young open cluster Collinder 228, and displays double-peaked emission in the centre of the Hα line which is characteristic of Be stars. We conclude by pointing out that the great promise of eclipsing binaries in open clusters can only be satisfied when both the binaries and their parent clusters are well-observed, a situation which is less common than we would like. 相似文献
11.
A sample of 51 separated binary systems with measured apsidal periods and rotational velocities of the components is examined. The ranges of the angles of inclination of the equatorial planes of the components to the orbital plane are estimated for these systems. The observed apsidal velocities can be explained by assuming that the axes of rotation of the stars are nonorthogonal to the orbital plane in roughly 47% of the systems (24 of the 51) and the rotation of the components is not synchronized with the orbital motion in roughly 59% of the systems (30 of 51). Nonorthogonality and nonsynchrony are defined as deviations from 90° and a synchronized angular velocity, respectively, at levels of 1 or more. 相似文献
12.
We will examine the properties of binary systems which have Roche lobe filling secondaries and white dwarf primaries as well
as systems where the secondary is only partially filling its Roche lobe. We will also discuss observational properties such
as ellipsoidal variations, light reprocessing and radial velocity measurements of the close binary systems BPM 71214, EC 13471-1258
and GD 245. The properties of BPM 71214 and EC 13471-1258 show that these systems may be pre-cataclysmic variables just prior
to the onset of mass transfer or they may be hibernating novae. GD 245 is a pre-cataclysmic variable. 相似文献
13.
We present a brief review of the recent results in modeling physical processes in strongly irradiated atmospheres of unevolved companions in precataclysmic binary systems (PCB) and their light curves. Constraints on physical parameters of the hot sdws primaries, thermal instability in upper irradiated atmosphere, monochromatic albedos, the deficit of the total emergent flux compared to the incoming flux from hot sdw primary are briefly discussed. 相似文献
14.
Vassiliki Kalogera 《Astrophysics and Space Science》2006,304(1-4):257-261
In the last few years Chandra observations have revolutionized the study of X-ray binaries by extending observed samples to extragalactic distances and stellar environments of varied star formation history. Here we summarize some of our results related to the interpretation of current observations of young star clusters and of elliptical galaxies. 相似文献
15.
Boris T. Gäansicke Domitilla De Martino Thomas R. Marsh Carole A. Haswell Christian Knigge Knox S. Long Steven N. Shore 《Astrophysics and Space Science》2006,303(1-4):53-68
Interacting Binaries consist of a variety of stellar objects in different stages of evolution and those containing accreting compact objects still represent a major challenge to our understanding of not only close binary evolution but also of the chemical evolution of the Galaxy. These end-points of binary star evolution are ideal laboratories for the study of accretion and outflow processes, and provide insight on matter under extreme physical conditions. One of the key-questions of fundamental relevance is the nature of SN Ia progenitors. The study of accreting compact binary systems relies on observations over the entire electromagnetic spectrum and we outline here those unresolved questions for which access to the ultraviolet range is vital, as they cannot be addressed by observations in any other spectral region.An erratum to this article can be found at 相似文献
16.
17.
Katalin Oláh 《Astrophysics and Space Science》2006,304(1-4):145-148
We obtain a class of transformations between Brans–Dicke (BD) scalar field conformal factor of the metric and the Klein–Gordon (KG) wave (its amplitude and phase), such that the BD action described by conformaly flat (CF) metrics is reduced to the KG action. We then present a modified theory as a causal Bohmian quantum gravity by using the quantum potential back reaction effects on the Minkowski background spacetime. We also derive Hamilton–Jacobi equations of the modified theory which is useful for obtaining its de Broglie pilot wave. 相似文献
18.
M. Jura 《Astrophysics and Space Science》1997,251(1-2):81-88
We propose that at least two stars on or near the AGB have long-lived orbiting disks: HD 44179, the central star in the Red
Rectangle, and BM Gem, a carbon-rich star with an oxygen-rich circumstellar envelope. The CO emission from both of these disks
has a spike with a width near ∼2 km s−1, indicating disk radii of ∼1016 cm. The dust in such disks is therefore quite cold (near T ∼ 50 K for the Red Rectangle) and may emit primarily at submillimeter
wavelengths. The disks around stars where there is also substantial mass loss may not be easily observable; there could be
many as yet undiscovered disks around AGB stars
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
19.
Mauri Valtonen 《Celestial Mechanics and Dynamical Astronomy》1997,68(1):27-41
The orbital properties of wide binaries are modified by stellar encounters during their lifetimes as field stars. The few body process is particularly efficient right after the star formation in star clusters. In this article we review the orbital parameters which we expect from the few-body process. First, the solutions of the General Three-Body Problem are described, and then a detailed discussion of the theory relevant to binaries follows. Among other things, Öpik's law of the distribution of semi- major axes of the binaries is derived. In addition, we summarize recent results from the few-body problem of extended bodies which may be relevant to the early dynamical evolution of protostellar clouds. 相似文献
20.
D. Mkrtichian S.-L. Kim A. V. Kusakin E. Rovithis-Livaniou P. Rovithis P. Lampens P. van Cauteren R. R. Shobbrook E. Rodriguez A. Gamarova E. C. Olson Y. W. Kang 《Astrophysics and Space Science》2006,304(1-4):169-171
We present a status report on the search for pulsations in primary componants of Algols systems (oEA stars). Analysis of 21 systems with A0-F2 spectral type primaries revealed pulsations in two systems suggesting that of the order of ten persent of Algols primaries in this range are actually pulsators. 相似文献