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1.
The eclipsing binary NN Vir is a short period system showing an EW‐type light curve. Photometric observations of NN Vir were done by Gomez‐Ferrellad & Garcia‐Melendo (1997) at Esteve Duran Observatory. We used photometric data of NN Vir for light curve analysis. The available spectroscopic data of NN Vir is new and we also used the first radial velocity data of this system obtained by Rusinski & Lu (1999) for analysis. The radial velocity and light curves analysis was made with the latest version ofWilson program(1998) and the geometric and physical elements of the system are derived. By searching the simultaneous solutions of the system, we have determined the masses and radii of the components : 1.89(M⊙) and 1.65(R⊙) for the primary component; 0.93(M⊙) and 1.23(R⊙) for the secondary component. We estimated effective temperatures of 7030(K) for the primary and 6977(K) for the secondary component. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
Complete UBV light curves of the W Ursae Majoris binary V839 Ophobtained in the year 2000 are presented. The available spectroscopic
data of V839 Oph is new and we used the first radial velocity data of this system obtained by Rucinski and Lu (1999)for analysis.
The radial velocity and light curves analysis was made with the latest version of Wilson programme (1998) and the geometric
and physical elements of the system are derived. By searching the simultaneous solutions of the system we have determined
the masses and radii of the components: 1.61M
⊙and 1.49402R
⊙ for the primary component; 0.50M
⊙and 0.90147R
⊙ for the secondary component. We estimate deffective temperatures of 6650±18 (K) for the primary and6554±15 (K) for the secondary
component.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
In this study complete BV light curves of the W Ursae Majoris binary V1073 Cygni obtained in 2005 are presented. We have used the spectroscopic data of V1073 Cyg obtained by Ahn et al. (1992) for analysis. The analysis of radial velocity and light curves was made with Wilson} program (1998) and the geometric and physical elements} of the system were derived. By searching the simultaneous} solutions of the system, we have determined the masses and radii of the components: 1.64M⊙, 2.275R⊙ for the primary component and 0.55M⊙, 1.397R⊙ for the secondary component respectively. The effective temperature of 6494 ± 53 K for the secondary component was also estimated. 相似文献
4.
L. V. Glazunova 《Astronomy Letters》2011,37(6):414-419
Based on two high-dispersion spectra of the close binary BW Boo, we have detected lines of the secondary component whose contribution
to the combined spectrum does not exceed 2%. We have determined the rotation velocities of the components and spectroscopic
orbital elements. Numerous lines of neutral and ionized iron have been used to determine the effective temperature and surface
gravity for the primary component. The photometric light curves for this binary have been solved for the first time. Its primary
component is an A2Vm star with a mass of 2 ± 0.1M
⊙ and a radius of 1.9 ± 0.4R
⊙. Its rotation velocity is 2 km s−1, which is a factor of 18 lower than the pseudo-synchronous velocity for this component. The G6 secondary component, a T Tau
star, has a rotation velocity of 17 km s−1, amass of 1.1M
⊙, and a radius of 1 R
⊙. The age of the binary has been estimated to be 107 yr. 相似文献
5.
We present the results of our infrared observations of WR 140 (=V1687 Cyg) in 2001–2010. Analysis of the observations has
shown that the J brightness at maximum increased near the periastron by about 0
m
.3; the M brightness increased by ∼2
m
in less than 50 days. The minimum J brightness and the minimum L and M brightnesses were observed 550–600 and 1300–1400 days after the maximum, respectively. The JHKLM brightness minimum was observed in the range of orbital phases 0.7–0.9. The parameters of the primary O5 component of the
binary have been estimated to be the following: R(O5) ≈ 24.7R
⊙, L(O5) ≈ 8 × 105
L
⊙, and M
bol(O5) ≈ −10
m
. At the infrared brightness minimum, T
g ∼ 820–880 K, R
g ≈ 2.6 × 105
R
⊙, the optical depth of the shell at 3.5 μm is ∼5.3 × 10−6, and its mass is ≈1.4 × 10−8
M
⊙. At the maximum, the corresponding parameters are ∼1300 K, 8.6 × 104
R
⊙, ∼2 × 10−4, and ∼6 × 10−8
M
⊙; the mean rate of dust inflow (condensation) into the dust structure is ∼3.3 × 10−8
M
⊙ yr−1. The mean escape velocity of the shell from the heating source is ∼103 km s−1 and the mean dispersal rate of the shell is ∼1.1 × 10−8
M
⊙ yr−1. 相似文献
6.
UBV photometric observations and elements of TT Hydrae obtained by Kulkarni and Abhyankar (1980) are combined with the radial
velocity curve of Popper (1979, personal communication) to derive the absolute dimensions and. a model of this important Algol
system. While the photometric ratios of radii inV andB are in agreement givingk = 0.3812 for a limb darkening coefficient ofx = 0.6, application of Irwin’s (1947) method givesx = 0.4 forU. The primary is found to be a main sequence Al V star of mass 2.61M
⊙ and radius 2.01 R⊙, and the secondary is classified as a Kl III star of mass 0.70M
⊙ and radius 5.33R
⊙. The observed Fourier coefficients for the light outside the eclipse agree with those calculated from theory for the reflection
and ellipticity effects. The system shows an ultraviolet excess of 0.5 to 0.6 magnitudes during primary eclipse, which is
attributed to an asymmetric circumstellar distribution of matter around the primary. The evolutionary status of the secondary,
which does not appear to fill its Roche lobe completely, is discussed. 相似文献
7.
F. Sánchez-Bajo E. García-Melendo J. M. Gómez-Forrellad 《Astrophysics and Space Science》2007,312(3-4):151-159
New ephemeris and the absolute parameters—masses, radii and luminosities—of the contact systems VW LMi and BX Dra have been
obtained, by means of the analysis of the minima data available in the literature (for the determination of the ephemeris)
and combining the previously published spectroscopic information and the results of the Wilson-Devinney method using photometric
data (for the determination of the absolute parameters). The VW LMi O−C analysis confirms the multiplicity of the system detected previously from the spectroscopic data. Masses of the VW LMi contact
system primary and secondary components are 1.67 ± 0.02M
⊙ and 0.70 ± 0.02M
⊙, respectively. The corresponding radii are 1.709 ± 0.007R
⊙ and 1.208 ± 0.006R
⊙, respectively. For the BX Dra contact system the masses are 2.19 ± 0.13M
⊙ and 0.63 ± 0.06M
⊙, and the radii, 2.13 ± 0.04R
⊙ and 1.26 ± 0.03R
⊙, for the primary and secondary, respectively. In both cases, the estimated luminosities seem to be slightly greater that
the values derived from the Hipparcos distances. 相似文献
8.
C. V. S. R. Sarma M. B. K. Sarma N. B. Sanwal 《Journal of Astrophysics and Astronomy》1989,10(3):307-346
The extensiveUBV observations of SV Camelopardalis by Patkos (1982) have been analysed to derive the orbital elements of the system. The data
were corrected for the effect of third body (Sarma, Sarma & Abhyankar 1985) and for the ‘RS CVn’ distortion wave (Sarma, Vivekanandarao
& Sarma 1988). The cleaned data were used to obtain a preliminary solution by a modified version of Wellmann method (Sarma
& Abhyankar 1979) from which we concluded that the primary eclipse is a transit. The final orbital elements of SV Cam were
obtained by the modified version (Sarma 1988; Sarmaet al. 1987) of WINK program by Wood (1972). The colour and median brightness variation are discussed. From the spectroscopic mass
functionf(m) = 0.118 M⊙ (Hiltner 1953), the absolute dimensions of the components are found to be 0.826 Mbd & 0.592 M⊙ and 1.236 R⊙ & 0.778 R⊙ for the primary and secondary components, respectively. The age of the binary system is estimated to be 6.0 ± 1.0 × 108 years 相似文献
9.
Atsuma Yamasaki 《Astrophysics and Space Science》2005,296(1-4):277-280
New BV light curves of the A-type W UMa star AQ Psc (P = 0.476d) have been observed and are described. A few times of minimum light are obtained and the ephemeris is improved.
The light curves are analyzed for the binary parameters with a light curve synthesis method. Combining the results with Lu
and Rucinski’s spectroscopic mass ratio we determined the masses and radii of the components: M
1 = 1.69M
⊙, M
2 = 0.38M
⊙, R
1 = 1.77R
⊙, and R
2 = 0.89R
⊙. 相似文献
10.
We present multi-colour CCD observations of the low-temperature contact binaries, V453 Mon and V523 Cas. Their light curves
are modelled to determine a new set of stellar and orbital parameters. Analysis of mid-eclipse times yields a new linear ephemeris
for both systems. A period decrease (dP/dt=2.3×10−7 days/yr) in V453 Mon is discovered. V523 Cas, however, is detected to show a period increase (dP/dt=9.8×10−8 days/yr) because of the mass transfer of a rate of 1.1×10−7 M⊙ yr−1, from a less massive donor. Using these findings we can determine the physical parameters of the components of V523 Cas to
be M
1=0.76 (3)M
⊙, M
2=0.39 (2)M
⊙, R
1=0.74 (2)R
⊙, R
2=0.55 (2)R
⊙, L
1=0.19 (3)L
⊙, L
2=0.14 (3)L
⊙, and the distance of system as 46(9) pc. 相似文献
11.
TheUBV light curves obtained by Duerbeck (1975) andHa (wide) and Ha (narrow) light curves obtained by Chambliss & Davan (1987) of the detached eclipsing binary VV Orionis (VV
Ori) were analysed using the Wilson-Devinney method fixing the two parametersT
h (25,000 K) and q(0.4172), resulting in the following absolute elements:A = 13.605 ± 0.03 LR⊙,R
h = 5.03 ±0.03R
⊙, Rc = 2.43 ±0.02R
⊙,M
bol,h
= -5.18 ± 0.11,M
bol,c
= -1.54 ± 0.06,m
h
=10.81 + 0.42m
⊙ andm
c
= 4.51 ± 0.41m
⊙. The de-reddened colours obtained from applying the reddening corrections ofE(B-V) = 0m.05 andE(U-B) = O
m
.04, and the derived temperatures of the components, gave spectral types ofB 1.5V for the primary and 54-5V with anUV excess of 0
m
·3 for the secondary component. A comparison of the logL and logT
e of the components with the observed ZAMS shows the primary component to be a little above and the secondary component to
be a little below/or on the ZAMS. A comparison of the properties of the components of VV Ori and a few other detached systems
with the normal stars in the logL, logR and logT
e versus logm planes, indicated a need for either a readjustment of the scales of the above parameters or modifications in the theoretical
models. From the position of the components on the evolutionary tracks of Pop I composition computed by Schaller et al. (1992)
it is noticed that while the primary component of W Ori had slightly evolved along the main-sequence, its secondary is still
unevolved. The age of VV Ori is found to be 10 ± 1 million years and it is at a distance of 368 ± 10 pc. 相似文献
12.
The photometric elements of the Algol type binary TT Hydrae derived by the authors from theirUBV observations during 1973–77 have been combined with the spectroscopic elements given by Sanford (1937) and Sahade and Cesco
(1946) to obtain the absolute dimensions of the system. It is found that the spectroscopic orbital elements given by Sanford
represent the evolutionary status of the secondary component better than those of Sahade and Cesco. The primary appears to
be an Al v main sequence star of mass
and radius ∼2.3R
⊙. The secondary fills its Roche lobe; it can be represented by a K0iii star of mass
and radius ∼6.0R
⊙. Better spectroscopic data are needed for confirmation of these results. 相似文献
13.
Cross correlations between observed and synthetic spectra are used to discover yet another satellite of BM Ori with the following
characteristics: effective temperature Teff = 4000 K, radius R = 16R⊙, mass M = 1.8M⊙, spectral type K7 III, absolute bolometric stellar magnitude Mb = + 4m·0, axial rotation velocity V sini = 85 km/s, and relative luminosity 0.005 near the V band.
__________
Translated from Astrofizika, Vol. 49, No. 1, pp. 111–120 (February 2006). 相似文献
14.
Synthetic light curve solutions for the W UMa-system VW Cep have been determined by applying the most new version of Wilson
(1998)approach to B-observations of 1996 and VRI-observations of 1999. From a consideration of the possible evolution of this
system, it is found that the system is a partial eclipsing contact one, and its primary to be a nearly Main-Sequence F5 star
of mass 0.85 M
⊙ and the secondary to be a dwarf of spectral type G0 of mass 0.34 M
⊙.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
B. Khalesseh 《Astrophysics and Space Science》1998,260(3):299-307
New radial velocity measurements of the Algol-type eclipsing binary AI Dra, based on Reticon observations, are presented.
The velocity measures themselves are based on fitting theoretical profiles, generated by a physical model of the binary, to
the observed cross-correlation function (ccf). Such profiles match this function very well, much better in fact that Gaussian
profiles which are generally used. Measuring the ccf's with Gaussian profiles yields following results: mp sin3 i=2.55± 0.05m⊙, ms sin3 i = 1.14 ± 0.03m⊙, (ap + as) sin i=7.34 ±0.05R⊙, and mp/ms =2.23± 0.05. Where as measuring the ccf's with theoretical profiles yields a mass ratio of 2.33 and following results:
mp sin3 i=2.84± 0.05m⊙, ms sin3 i=1.22 ± 0.03m⊙, (ap +as) sin i=7.56± 0.05R⊙.
The system comprising a semi-detached configuration. From the solution of a previously published light curved and combining
it's results with the spectroscopic orbit, one can lead to the following physical parameters: mp =2.99m⊙, ms =1.28m⊙, > Tp < =9600 K, > Ts < =5400 K, > Rp < =2.35R⊙, > Rs < =2.12R⊙. The system comprising an AO primary and a secondary of G2 spectral type.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Evolutionary stellar models of FG Vir have been developed theoretically and are compared with earlier observational results.
Using the models, we performed calculations to obtain radial and non-radial adiabatic oscillation frequencies. The results
show that, if the observational splitting was considered and the observational mode identifications were followed, 1.85M
⊙ star models with the rotational velocities in the range from 32 to 66 kms−1 seem to be representative models of FG Vir. 相似文献
17.
Yu. A. Fadeyev 《Astronomy Letters》2011,37(6):403-413
Instability of population I (X = 0.7, Z = 0.02) massive stars against radial oscillations during the post-main-sequence gravitational contraction of the helium core
is investigated. Initial stellar masses are in the range 65M
⊙ ≤ M
ZAMS ≤ 90M
⊙. In hydrodynamic computations of self-exciting stellar oscillations we assumed that energy transfer in the envelope of the
pulsating star is due to radiative heat conduction and convection. The convective heat transfer was treated in the framework
of the theory of time-dependent turbulent convection. During evolutionary expansion of outer layers after hydrogen exhaustion
in the stellar core the star is shown to be unstable against radial oscillations while its effective temperature is T
eff > 6700 K for M
ZAMS = 65M
⊙ and T
eff > 7200 K for M
ZAMS = 90M
⊙. Pulsational instability is due to the κ-mechanism in helium ionization zones and at lower effective temperature oscillations decay because of significantly increasing
convection. The upper limit of the period of radial pulsations on this stage of evolution does not exceed ≈200 day. Radial
oscillations of the hypergiant resume during evolutionary contraction of outer layers when the effective temperature is T
eff > 7300 K for M
ZAMS = 65M
⊙ and T
eff > 7600 K for M
ZAMS = 90M
⊙. Initially radial oscillations are due to instability of the first overtone and transition to fundamental mode pulsations
takes place at higher effective temperatures (T
eff > 7700 K for M
ZAMS = 65M
⊙ and T
eff > 8200 K for M
ZAMS = 90M
⊙). The upper limit of the period of radial oscillations of evolving blueward yellow hypergiants does not exceed ≈130 day.
Thus, yellow hypergiants are stable against radial stellar pulsations during the major part of their evolutionary stage. 相似文献
18.
19.
We investigate numerically the chemodynamical evolution of major disc–disc galaxy mergers in order to explore the origin of
the mass-dependent chemical, photometric and spectroscopic properties observed in elliptical galaxies. We investigate especially
the dependence of the fundamental properties on merger progenitor disc mass (M
d). Three main results are obtained in this study:– More massive (luminous) ellipticals formed by galaxy mergers between more
massive spirals have higher metallicity (Z) and thus show redder colours; the typical metallicity ranges from ∼ 1.0 solar abundance (Z∼ 0.02) for ellipticals formed by mergers with M
d = 1010
M
⊙to ∼ 2.0 solar (Z∼ 0.04) for those with M
d= 1012
M
⊙.– Both the Mg2 line index in the central part of ellipticals (R ≤ 0.1 R
e) and the radial gradient of Mg2 (δ Mg2 / δ log R) are more likely to be larger for massive ellipticals. δ Mg2 / δ log R correlates reasonably well with the central Mg2 in ellipticals. For most of the present merger models, ellipticals show a positive radial gradient of the Hβ line index. – Both M/L
B and M/L
K (where M, L
B, and L
K are the total stellar mass of galaxy mergers, the B-band and the K-band luminosities, respectively) depend on galactic mass in such a way that more massive ellipticals have larger M/L
B and smaller M/L
K.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
A compact structure of a low-mass Type I presupernovae is assumed to be an essential feature of the hydrodynamical problem
dealing with the supernova Type I (SNI) envelope outbursts. This structure is characterized by a degenerate carbon-oxygen
core, which suffers a thermonuclear explosion of carbon fuel (M
0≃1.40M
⊙), and by a compact lowmass envelope (M
e
≲0.1M
⊙) with external radiusR
e≃109 cm. The parameters, of this hydrostatic envelope are specified and then, for a relatively small explosion energy, ofW
0≃(2–10)×1049 erg, hydrodynamic problem of the envelope ejection is solved numerically. This energy comes from neutrino-induced detonative
carbon burning. The resulting structure of the SNI atmosphere expanding with the velocity gradient can be employed for an
interpretation of the observed SNI spectra. In accordance with our previous papers, the SNI light curves are considered to
occur due to an additional slow (with time-scale 106–107 s) release of the bulk of the SNI energy,W≃1051, erg. The slow energy release does not, however, affect the structure of the outermost expanding layers of the envelope which
are responsible for the SNI spectra.
A short (Δt≃10−2 s) burst of soft (2–10 keV) X-rays with total radiated energy of about 1040 erg is found to appear 10–20 days before the SNI optical maximum. 相似文献