We present ∼ 800 days of photometric monitoring of Boyajian's Star (KIC 8462852) from the All-Sky Automated Survey for Supernovae (ASAS-SN) and ∼ 4000 days of monitoring from the All Sky Automated Survey (ASAS). We show that from 2015 to the present the brightness of Boyajian's Star has steadily decreased at a rate of 6.3 ± 1.4 mmag yr −1 , such that the star is now 1.5% fainter than it was in February 2015. Moreover, the longer time baseline afforded by ASAS suggests that Boyajian's Star has also undergone two brightening episodes in the past 11 years, rather than only exhibiting a monotonic decline. We analyze a sample of ∼ 1000 comparison stars of similar brightness located in the same ASAS-SN field and demonstrate that the recent fading is significant at 99.4% confidence. The 2015 − 2017 dimming rate is consistent with that measured with Kepler data for the time period from 2009 to 2013. This long-term variability is difficult to explain with any of the physical models for the star's behavior proposed to date.
RESUMENSe examinan las historias orbitales de los sistemas Sirio AB, Procion AB, 40 Eri BC y Stein 2051 AB. Se supone que los cambios en los elementos orbitales son el resultado directo de la perdida de masa de la componente progenitora de la enana blanca.La suposicion de que esta perdida de masa es isotropica y que no hay intercambio de masa entre las componentes, junto con las historias orbitales, las abundancias atmosfericas observadas, edades teoricas y tiempos de enfriamiento nos llevan a la conclusion que estrellas tan masivas como 10M o pueden ser progenitoras de enanas blancas. En efecto, en el caso de Sirio B hay evidencia que la masa de la progenitora no era menor de 8M Q y que la estrella no perdio masa en forma explosiva.
ABSTRACTThe orbital histories of the systems Sirius AB, Procyon AB, 40 Eri BC and Stein 2051 AB are examined. It is assumed that the changes in the orbital elements are a direct result of mass loss from the white dwarf precursor component. This loss is considered to be isotropic and no exchange between the components is allowed. These histories, coupled with observed atmospheric abundances, theoretical ages and cooling times lead to the conclusion that stars as massive as 1OM 0 can be white dwarf progenitors. Indeed, in the case of Sirius B, there is evidence that the progenitor mass was not less than 8M Q and that the star did not lose mass in an explosive manner.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.