Browsing by Author "Carmo, A."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Recovering Algol-type eclipsing binaries in the CRTS
    (2020) Carmo, A.; Ferreira Lopes, C. E.; Papageorgiou, A.; Jablonski, F. J.; Rodrigues, C. V.; Drake, A. J.; Cross, N. J. G.; Catelan , Marcio
    Eclipsing binary systems are relevant to astronomy since they provide primary means of determining fundamental stellar astrophysical quantities such as mass, radius, and temperature of the components. Algol-type eclipsing binaries (EAs) have spherical or slightly ellipsoidal components and are generally systems that produce light curves with narrow eclipses and few points within the eclipse. The most current photometric surveys usually have observation cadences larger than these eclipses duration, which hinders the detection of EAs. The variability of these objects can even be detected, but the period is rarely found because an optimized constraint is required. Thereby, we used a new methodology to find new EAs in the Catalina Real-Time Transient Survey. As a result, we determined periodicity for 56\% of EA$_\mathrm{up}$ (EAs marked as having unknown period), which corresponds to 87 new EAs reported. Also, we use color criteria to select a subsample that contains 8 low-mass binary systems with spectral types K and M. To obtain the individual physical parameters of these components, each light curve was modeled with the Wilson & Devinney light curve synthesis code combined with a Monte Carlo Markov chain process. The results were examined in the scenario of radius inflation of low-mass stars in binary systems....
  • No Thumbnail Available
    Item
    Recovering variable stars in large surveys: EAup Algol-type class in the Catalina Survey
    (OUP, 2020) Carmo, A.; Ferreira Lopes, C. E.; Papageorgiou, A.; Jablonski, F. J.; Rodrigues, C. V.; Drake, A. J.; Cros, N. J. G.; Catelan, Márcio
    The discovery and characterization of Algol eclipsing binaries (EAs) provide an opportunity to contribute for a better picture of the structure and evolution of low-mass stars. However, the cadence of most current photometric surveys hinders the detection of EAs since the separation between observations is usually larger than the eclipse(s) duration and hence few measurements are found at the eclipses. Even when those objects are detected as variable, their periods can be missed if an appropriate oversampling factor is not used in the search tools. In this paper, we apply this approach to find the periods of stars catalogued in the Catalina Real-Time Transient Survey (CRTS) as EAs having unknown period (EA up ). As a result, the periods of ∼56percent of them were determined. Eight objects were identified as low-mass binary systems and modelled with the Wilson & Devinney synthesis code combined with a Markov chain Monte Carlo optimization procedure. The computed masses and radii are in agreement with theoretical models and show no evidence of inflated radii. This paper is the first of a series aiming to identify suspected binary systems in large surveys.