New luminous blue variable candidates in the NGC 247 galaxyстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 30 декабря 2020 г.
Аннотация:We search for luminous blue variable (LBV) stars in galaxies outside the Local Group. Here we present a study of two bright Hα sources in the NGC 247 galaxy. Object j004703.27-204708.4 (MV = −9.08 ± 0.15 mag) shows the spectral lines typical for well-studied LBV stars: broad and bright emission lines of hydrogen and helium He I with P Cyg profiles, emission lines of iron Fe II, silicon Si II, nitrogen N II and carbon C II, forbidden iron [Fe II] and nitrogen [N II] lines. The variability of the object is ∆B = 0.74 ± 0.09 mag and ∆V = 0.88 ± 0.09 mag, which makes it a reliable LBV candidate. The star j004702.18-204739.93 (MV = −9.66 ± 0.23 mag) shows many emission lines of iron Fe II, forbidden iron lines [Fe II], bright hydrogen lines with broad wings, and also forbidden lines of oxygen [O I] and calcium [Ca II] formed in the circumstellar matter. The study of the light curve of this star did not reveal significant variations in brightness (∆V = 0.29 ± 0.09 mag). We obtained estimates of interstellar absorption, the photosphere temperature, as well as bolometric magnitudes Mbol=−10.5+0.5−0.4 and Mbol=−10.8+0.5−0.6, which correspond to bolometric luminosities log(Lbol/L⊙)=6.11+0.20−0.16 and 6.24+0.20−0.25 for j004703.27-204708.4 and j004702.18-204739.93, respectively. Thus, the object j004703.27-204708.4 remains a reliable LBV candidate, while the object j004702.18-204739.93 can be classified as a B[e]-supergiant.