ترغب بنشر مسار تعليمي؟ اضغط هنا

OGLE-BLG182.1.162852: An Eclipsing Binary with a Circumstellar Disk

271   0   0.0 ( 0 )
 نشر من قبل Nicholas Rattenbury
 تاريخ النشر 2014
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We present the discovery of a plausible disk-eclipse system OGLE-BLG182.1.162852. The OGLE light curve for OGLE-BLG182.1.162852 shows three episodes of dimming by $I simeq 2 - 3$ magnitudes, separated by 1277 days. The shape of the light curve during dimming events is very similar to that of known disk eclipse system OGLE-LMC-ECL-11893 (Dong et al. 2014). The event is presently undergoing a dimming event, predicted to end on December 30th, 2014. We encourage spectroscopic and multi-band photometric observations now. The next dimming episode for OGLE-BLG182.1.162852 is expected to occur in March 2018.



قيم البحث

اقرأ أيضاً

We investigate the nature of the unusual eclipsing star OGLE LMC-ECL-11893 (OGLE J05172127-6900558) in the Large Magellanic Cloud recently reported by Dong et al. 2014. The eclipse period for this star is 468 days, and the eclipses exhibit a minimum of ~1.4 mag, preceded by a plateau of ~0.8 mag. Spectra and optical/IR photometry are consistent with the eclipsed star being a lightly reddened B9III star of inferred age ~150 Myr and mass of ~4 solar masses. The disk appears to have an outer radius of ~0.2 AU with predicted temperatures of ~1100-1400 K. We model the eclipses as being due to either a transiting geometrically thin dust disk or gaseous accretion disk around a secondary object; the debris disk produces a better fit. We speculate on the origin of such a dense circumstellar dust disk structure orbiting a relatively old low-mass companion, and on the similarities of this system to the previously discovered EE Cep.
80 - Z.T Han , S.B. Qian , L.Y. Zhu 2018
We present a timing analysis of the eclipsing post-common envelope binary (PCEB) DE CVn. Based on new CCD photometric observations and the published data, we found that the orbital period in DE CVn has a cyclic period oscillation with an amplitude of $28.08$ s and a period of $11.22$ years plus a rapid period decrease at a rate of $dot{P}=-3.35times10^{-11}ss^{-1}$. According to the evolutionary theory, secular period decreases in PCEBs arise from angular momentum losses (AMLs) driven by gravitational radiation (GR) and magnetic braking (MB). However, the observed orbital decay is too fast to be produced by AMLs via GR and MB, indicating that there could be other AML mechanism. We suggest that a circumbinary disk around DE CVn may be responsible for the additional AML. The disk mass was derived as a few$times$$10^{-4}$-$10^{-3}$$M_{odot}$ , which is in agreement with that inferred from previous studies in the order of magnitude. The cyclic change is most likely result of the gravitational perturbation by a circumbinary object due to the Applegates mechanism fails to explain such a large period oscillation. The mass of the potential third body is calculated as $M_{3}sin{i}=0.011(pm0.003)M_{odot}$. Supposing the circumbinary companion and the eclipsing binary is coplanar, its mass would correspond to a giant planet. This hypothetical giant planet is moving in a circular orbit of radius $sim5.75(pm2.02)$ AU around its host star.
We analyze the CoRoT and V-passband ground-based light curves of the interacting close binary AU Mon, assuming that there is a geometrically and optically thick accretion disk around the hotter and more massive star, as inferred from photometric and spectroscopic characteristics of the binary. Our model fits the observations very well and provides estimates for the orbital elements and physical parameters of the components and of the accretion disk.
BVR light curves and radial velocities for the double-lined eclipsing binary V1135,Her were obtained. The brighter component of V1135,Her is a Cepheid variable with a pulsation period of 4.22433$pm$0.00026 days. The orbital period of the system is ab out 39.99782$pm$0.00233 days, which is the shortest value among the known Type,II Cepheid binaries. The observed B, V, and R magnitudes were cleaned for the intrinsic variations of the primary star. The remaining light curves, consisting of eclipses and proximity effects, are obtained. Our analyses of the multi-colour light curves and radial velocities led to the determination of fundamental stellar properties of both components of the interesting system V1135,Her. The system consists of two evolved stars, G1+K3 between giants and supergiants, with masses of M$_1$=1.461$pm$0.054 Msun ~and M$_2$=0.504$pm$0.040 {Msun} and radii of R$_1$=27.1$pm$0.4 {Rsun} and R$_2$=10.4$pm$0.2 {Rsun}. The pulsating star is almost filling its corresponding Roche lobe which indicates the possibility of mass loss or transfer having taken place. We find an average distance of d=7500$pm$450 pc using the BVR magnitudes and also the V-band extinction. Location in the Galaxy and the distance to the galactic plane with an amount of 1300 pc indicate that it probably belongs to the thick-disk population. Most of the observed and calculated parameters of the V1135,Her and its location on the color-magnitude and period-luminosity diagrams lead to a classification of an Anomalous Cepheid.
We use ASAS V-band and ASAS-SN g-band observations to model the long-period detached eclipsing binary ASASSN-21co. ASAS observations show an eclipse of depth V ~ 0.6 mag in April of 2009. ASAS-SN g-band observations from March of 2021 show an eclipse of similar duration and depth, suggesting an orbital period of 11.9 years. We combine the g-band observations with additional BVRI photometry taken during the eclipse to model the eclipse using PHOEBE. We find that the system is best described by two M giants with a ratio of secondary radius to primary radius of ~0.61. Optical spectra taken during the eclipse are consistent with at least one component of the binary being an M giant, and we find no temporal changes in the spectral features. The eclipse itself is asymmetric, showing an increase in brightness near mid-eclipse, likely due to rotational variability that is too low amplitude to be observed out-of-eclipse.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا