اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدPrecise mass and radius measurements for the components of the bright solar-type eclipsing binary star V1094 Tau
42
0
0.0
(
0
)
تأليف
P. F. L. Maxted
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
V1094 Tau is bright eclipsing binary star with an orbital period close to 9 days containing two stars similar to the Sun. Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau. We present new spectroscopy of V1094 Tau which we use to estimate the effective temperatures of both stars and to refine their spectroscopic orbits. We also present new, high-quality photometry covering both eclipses of V1094 Tau in the Stroemgren uvby system and in the Johnson V-band. The masses, radii and effective temperatures of the stars in V1094 Tau are found to be M$_A$ = 1.0965 $pm$ 0.0040 M$_{odot}$, R$_A$ = 1.4109 $pm$ 0.0058 R$_{odot}$, T$_{rm eff,A}$ = 5850 $pm$ 100 K, and M$_B$ = 1.0120 $pm$ 0.0028 M$_{odot}$, R$_B$ = 1.1063 $pm$ 0.0066 R$_{odot}$, T$_{rm eff,B}$ = 5700 $pm$ 100 K. An analysis of the times of mid-eclipse and the radial velocity data reveals apsidal motion with a period of 14500 $pm$ 3700 years. The observed masses, radii and effective temperatures are consistent with stellar models for an age $approx$ 6 Gyr if the stars are assumed to have a metallicity similar to the Sun. This estimate is in reasonable agreement with our estimate of the metallicity derived using Stroemgren photometry and treating the binary as a single star ([Fe/H] $= -0.09 pm 0.11$). The rotation velocities of the stars suggest that V1094 Tau is close to the limit at which tidal interactions between the stars force them to rotate pseudo-synchronously with the orbital motion.
قيم البحث
اقرأ أيضاً
We report the discovery of KELT J041621-620046, a moderately bright (J$sim$10.2) M dwarf eclipsing binary system at a distance of 39$pm$3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extre
mely Little Telescope (KELT) survey. The system has a short orbital period of $sim$1.11 days and consists of components with M$_1$ = $0.447^{-0.047}_{+0.052},M_odot$ and M$_2$ = $0.399^{-0.042}_{+0.046},M_odot$ in nearly circular orbits. The radii of the two stars are R$_1$ = $0.540^{-0.032}_{+0.034},R_odot$ and R$_2$ = $0.453pm0.017,R_odot$. Full system and orbital properties were determined (to $sim$10% error) by conducting an EBOP global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17-28% and cooler by 4-10% than predicted by standard (non-magnetic) stellar models. Strong H$alpha$ emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.
PSR J1829+2456 is a radio pulsar in a relativistic binary system with another neutron star. It has a rotational period of 41 ms and a mildly eccentric ($e = 0.14$) 28-hr orbit. We have continued its observations with the Arecibo radio telescope and h
ave now measured the individual neutron star masses of this system. The pulsar and companion masses are $1.306,pm,0.007,M_{odot}$ and $1.299,pm,0.007,M_{odot}$ (2$sigma$ - 95% confidence, unless stated otherwise), respectively. We have also measured the proper motion for this system and used it to estimate a space velocity of 49$^{+77}_{-30}$ km s$^{-1}$ with respect to the local standard of rest. The relatively low values for companion mass, space velocity and orbital eccentricity in this system make it similar to other double neutron star systems in which the second-formed neutron star is thought to have formed in a low-kick, low mass-loss, symmetric supernova.
Cool subdwarfs are metal-poor low-mass stars that formed during the early stages of the evolution of our Galaxy. Because they are relatively rare in the vicinity of the Sun, we know of few cool subdwarfs in the solar neighbourhood, and none with both
the mass and the radius accurately determined. This hampers our understanding of stars at the low-mass end of the main-sequence. Here we report the discovery of SDSSJ235524.29+044855.7 as an eclipsing binary containing a cool subdwarf star, with a white dwarf companion. From the light-curve and the radial-velocity curve of the binary we determine the mass and the radius of the cool subdwarf and we derive its effective temperature and luminosity by analysing its spectral energy distribution. Our results validate the theoretical mass-radius-effective temperature-luminosity relations for low-mass low-metallicity stars.
We observed spectroscopically the eclipsing binary system T-Cyg1-01385 in order to determine physical properties of the components. The double-lined nature of the system is revealed for the first time and the radial velocities are obtained for both s
tars. We have derived masses, radii and luminosities for both components. Analyses of the radial velocities and the KeplerCam and the T$r$ES light curves yielded masses of M$_1$=1.059$pm$0.032 Msun ~and M$_2$=0.342$pm$0.017 {Msun} and radii of R$_1$=1.989$pm$0.022 {Rsun} and R$_2$=0.457$pm$0.013 {Rsun}. Locations of the low-mass companion in the mass-radius and mass-effective temperature planes and comparison with the other low-mass stars show that the secondary star appears just at the transition from partially to fully convective interiors for the M dwarfs. When compared to stellar evolution models, the luminosities and effective temperatures of the components are consistent with Z=0.004 and an age of about 6 Gyr. A distance to the system was calculated as d=355$pm$7 pc using the BV and JHK magnitudes.
Early-type magnetic stars are rarely found in close binary systems. No such objects were known in eclipsing binaries prior to this study. Here we investigated the eclipsing, spectroscopic double-lined binary HD66051, which exhibits out-of-eclipse pho
tometric variations suggestive of surface brightness inhomogeneities typical of early-type magnetic stars. Using a new set of high-resolution spectropolarimetric observations, we discovered a weak magnetic field on the primary and found intrinsic, element-dependent variability in its spectral lines. The magnetic field structure of the primary is dominated by a nearly axisymmetric dipolar component with a polar field strength $B_{rm d}approx600$ G and an inclination with respect to the rotation axis of $beta_{rm d}=13^{rm o}$. A weaker quadrupolar component is also likely to be present. We combined the radial velocity measurements derived from our spectra with archival optical photometry to determine fundamental masses (3.16 and 1.75 $M_odot$) and radii (2.78 and 1.39 $R_odot$) with a 1-3% precision. We also obtained a refined estimate of the effective temperatures (13000 and 9000 K) and studied chemical abundances for both components with the help of disentangled spectra. We demonstrate that the primary component of HD66051 is a typical late-B magnetic chemically peculiar star with a non-uniform surface chemical abundance distribution. It is not an HgMn-type star as suggested by recent studies. The secondary is a metallic-line star showing neither a strong, global magnetic field nor intrinsic spectral variability. Fundamental parameters provided by our work for this interesting system open unique possibilities for probing interior structure, studying atomic diffusion, and constraining binary star evolution.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
