ANÁLISE DE DADOS ESPETROSCÓPICOS E FOTOMÉTRICOS DE ESTRELAS VARIÁVEIS AZUIS LUMINOSAS

Abstract

Some of the brightest stars undergo sporadic and intense mass loss events, whose origins have not yet been fully understood. These hot and evolved stars are referred to as Luminous Blue Variables (LBVs), and their instability can significantly influence the appearance of the upper HR diagram. In this context, a bibliographic review was conducted in search of stars classified as LBVs or LBV candidates (cLBVs) that may be undergoing eruptions or have experienced recent substantial variability events. The goal was to analyze their historical light curves and spectra for new eruptions. Classical LBVs have luminosities on the order of 6 $\times$ $10^{6}$ \ls, suggesting an initial mass exceeding 50 \ms. There is also a group of less luminous LBVs (\textit{L} $\leq$ 6 $\times$ $10^{5}$ \ls) with lower mass loss rates. LBVs in general have high temperatures (\tef\ > 10,000 K); however, during eruptive periods, their temperatures can drop to values below 7,000 K. In this work, we highlight 15 stars classified as LBV or candidates that exhibit variability equal to or greater than 0.3 magnitudes, enabling a more detailed investigation of their spectra and light curves. Of these 15, nine are widely studied stars in the literature, including Eta Carinae, while six are LBVs with fewer prior studies. For the nine most well-documented LBVs, it was possible to obtain light curves covering eruptions and historical minima. With the exception of HR Carinae, more recent data (from 2020 to 2023) were also collected, providing insights into their current states. Despite the scarcity of data for the other six stars, variabilities were identified in all of them, some with variations of 0.3 mag and others close to one magnitude, such as AE And. Among all the stars, recent spectroscopic data were obtained for RMC 40, RMC 71, RMC 110, and unpublished data for WRAY 17-96. The persistence of stars RMC 40, RMC 71, and RMC 110 in their eruptive states is highlighted, along with a discussion of the spectroscopic behavior in the optical of WRAY 17-96, which exhibits well-defined P Cygni profiles. LBV; Photometry; Spectroscopy; Light curves.