اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدFirst Resolved Images of the Eclipsing and Interacting Binary Beta Lyrae
182
0
0.0
(
0
)
تأليف
M. Zhao
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present the first resolved images of the eclipsing binary Beta Lyrae, obtained with the CHARA Array interferometer and the MIRC combiner in the H band. The images clearly show the mass donor and the thick disk surrounding the mass gainer at all six epochs of observation. The donor is brighter and generally appears elongated in the images, the first direct detection of photospheric tidal distortion due to Roche-lobe filling. We also confirm expectations that the disk component is more elongated than the donor and is relatively fainter at this wavelength. Image analysis and model fitting for each epoch were used for calculating the first astrometric orbital solution for Beta Lyrae, yielding precise values for the orbital inclination and position angle. The derived semi-ma jor axis also allows us to estimate the distance of Beta Lyrae; however, systematic differences between the models and the images limit the accuracy of our distance estimate to about 15%. To address these issues, we will need a more physical, self-consistent model to account for all epochs as well as the multi-wavelength information from the eclipsing light curves.
قيم البحث
اقرأ أيضاً
We present the first Doppler images of the active eclipsing binary system SZ Psc, based on the high-resolution spectral data sets obtained in 2004 November and 2006 September--December. The least-squares deconvolution technique was applied to derive
high signal-to-noise profiles from the observed spectra of SZ Psc. Absorption features contributed by a third component of the system were detected in the LSD profiles at all observed phases. We estimated the mass and period of the third component to be about $0.9 M_{odot}$ and $1283 pm 10$ d, respectively. After removing the contribution of the third body from the LSD profiles, we derived the surface maps of SZ Psc. The resulting Doppler images indicate significant starspot activities on the surface of the K subgiant component. The distributions of starspots are more complex than that revealed by previous photometric studies. The cooler K component exhibited pronounced high-latitude spots as well as numerous low- and intermediate-latitude spot groups during the entire observing seasons, but did not show any large, stable polar cap, different from many other active RS CVn-type binaries.
We present Doppler images of both components of the eclipsing binary system ER Vul, based on the spectra obtained in 2004 November, 2006 September and 2008 November. The least-squares deconvolution technique is used for enhancing the signal-to-noise
ratios of the observed profiles. The new surface images reveal that both stars of ER Vul show strong starspot activities and the starspots appear at various latitudes. The surface maps of 2006 and 2008 both show the presence of large high-latitude starspots on each component of ER Vul. We find no obvious phase shift of the active regions during our observations. The longitude distributions of starspots are non-uniform on both stars. At low-to-mid latitudes, the active regions are almost exclusively found in the hemisphere facing the other star. However, we find no pronounced concentration of spots at the sub-stellar points.
Double Periodic Variables (DPV) are among the new enigmas of semi-detached eclipsing binaries. These are intermediate-mass binaries characterized by a long photometric period lasting on average 33 times the orbital period. We present a spectroscopic
and photometric study of the DPV V495 Cen based on new high-resolution spectra and the ASAS V-band light curve. We have determined an improved orbital period of $33.492 pm 0.002$ d and a long period of 1283 d. We find a cool evolved star of $M_{2}=0.91pm 0.2 M_{odot}$, $T_{2}= 6000pm 250 K$ and $R_{2}=19.3 pm 0.5 R_{odot}$ and a hot companion of $M_{1}= 5.76pm 0.3 M_{odot}$, $T_{1}=16960pm 400 K$ and $R=4.5pm0.2 R_{odot}$. The mid-type B dwarf is surrounded by a concave and geometrically thick disc, of radial extension $R_{d}= 40.2pm 1.3 R_{odot}$ contributing $sim$ 11 percent to the total luminosity of the system at the V band. The system is seen under inclination $84.!!^{circ}8$ $pm$ $0.!!^{circ}6$ and it is at a distance $d= 2092 pm 104.6$ pc. The light curve analysis suggests that the mass transfer stream impacts the external edge of the disc forming a hot region 11 % hotter than the surrounding disc material. The persistent $V<R$ asymmetry of the H$alpha$ emission suggests the presence of a wind and the detection of a secondary absorption component in He I lines indicates a possible wind origin in the hotspot region.
V453 Cyg is an eclipsing binary containing 14 Msun and 11 Msun stars in an eccentric short-period orbit. We have discovered $beta$ Cep-type pulsations in this system using TESS data. We identify seven significant pulsation frequencies, between 2.37 a
nd 10.51 d$^{-1}$, in the primary star. These include six frequencies which are separated by yet significantly offset from harmonics of the orbital frequency, indicating they are tidally-perturbed modes. We have determined the physical properties of the system to high precision: V453 Cyg A is the first $beta$ Cep pulsator with a precise mass measurement. The system is a vital tracer of the physical processes that govern the evolution of massive single and binary stars.
Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon. We derived
new, accurate ephemerides for both the orbital motion (with a period of 11.113d) and the long-term, overall brightness variation (with a period of 416.9d) of this strongly interacting Be + G semi-detached binary. It is shown that this long-term variation must be due to attenuation of the total light by some variable circumbinary material. We derived the binary mass ratio $M_{rm G}/M_{rm B}$ = 0.17p0.03 based on the assumption that the G-type secondary fills its Roche lobe and rotates synchronously. Using this value of the mass ratio as well as the radial velocities of the G-star, we obtained a consistent light curve model and improved estimates of the stellar masses, radii, luminosities and effective temperatures. We demonstrate that the observed lines of the B-type primary may not be of photospheric origin. We also discover rapid and periodic light changes visible in the high-quality residual CoRoT light curves. AU Mon is put into perspective by a comparison with known binaries exhibiting long-term cyclic light changes.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
