author = "Almeida, L. A. and Damineli, A. and Rodrigues, Cl{\'a}udia Vilega 
                         and Pereira, Marildo Geraldete and Jablonski, Francisco",
          affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Universidade Estadual de Feira de Santana} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "HS-2231+2441: an HW Vir system composed of a low-mass white dwarf 
                         and a brown dwarf-",
              journal = "Monthly Notices of The Royal Astronomical Society",
                 year = "2017",
               volume = "472",
               number = "3",
                pages = "3093--3100",
             keywords = "Estrelas bin{\'a}rias, Estrelas Quentes, Espectroscopia 
                         {\'o}ptica, Fotometria.",
             abstract = "HW Vir systems are rare evolved eclipsing binaries composed of a 
                         hot compact star and a low-mass main sequence star in a close 
                         orbit. These systems provide a direct way to measure the 
                         fundamental properties, e.g. masses and radii, of their 
                         components, hence they are crucial in studying the formation of 
                         subdwarf B stars and low-mass white dwarfs, the commonenvelope 
                         phase and the pre-phase of cataclysmic variables. Here, we present 
                         a detailed study of HS 2231+2441, an HW Vir type system, by 
                         analysing BVRCIC photometry and phaseresolved optical 
                         spectroscopy. The spectra of this system, which are dominated by 
                         the primary component features, were fitted using non-local 
                         thermodynamic equilibrium models providing an effective 
                         temperature Teff = 28 500  500 K, surface gravity log g = 5.40  
                         0.05 cm s\−2 and helium abundance log (n(He)/n(H)) = 
                         \−2.52  0.07. The geometrical orbit and physical 
                         parameters were derived by simultaneously modelling the 
                         photometric and spectroscopic data using the WilsonDevinney code. 
                         We derive two possible solutions for HS 2231+2441 that provide the 
                         component masses: M1 = 0.19 Mand M2 = 0.036 Mor M1 = 0.288 M and 
                         M2 = 0.046 M. Considering the possible evolutionary channels for 
                         forming a compact hot star, the primary of HS 2231+2441 probably 
                         evolved through the red-giant branch scenario and does not have a 
                         helium-burning core, which is consistent with a low-mass white 
                         dwarf. Both solutions are consistent with a brown dwarf as the 
                         secondary. Ke.",
                  doi = "10.1093/mnras/stx2150",
                  url = "http://dx.doi.org/10.1093/mnras/stx2150",
                 issn = "0035-8711 and 1365-2966",
                label = "lattes: 9527193250756102 3 AlmeidaDamRodPerJab:2017:HWViSy",
             language = "en",
           targetfile = "almeida_hs.pdf",
        urlaccessdate = "23 jan. 2021"