Перегляд за Автор "Kuratova, A. K."

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  • Ескіз
    Документ
    Spectroscopic monitoring of the b[e] objects FS CMA and MO CAM
    (Одеський національний університет імені І. І. Мечникова, 2019) Kuratova, A. K.; Miroshnichenko, A. S.; Zharikov, S. V.; Manset, N.; Khokhlov, S. A.; Raj, A.; Kusakin, A. V.; Reva, I. V.; Kokumbaeva, R. I.; Usenko, I. A.; Knyazev, A. Y.
    T. Objects with the B[e] phenomenon exhibit permitted and forbidden emission lines due to the presence of circumstellar ionized gas and large infrared excesses due to processing of the stellar radiation by circumstellar dust. There are five groups of stars that show this phenomenon (pre-main-sequence Herbig Ae/Be stars, symbiotic systems, proto-planetary nebulae, some supergiant, and FS CMa type objects). The latter group is the most recently discovered and the least explored. The leading hypothesis about the group nature implies that they are mostly intermediate-mass binary systems, whose circumstellar medium was created during a strong mass-transfer phase due to a Roche lobe overflow of the more massive star in the system. We have been conducting a large program of spectroscopic and photometric observations of many objects and candidates to this group. The current report is devoted to the preliminary results of our ongoing study of two objects with similar underlying early B-type stars, FS CMa (the group prototype) and MO Cam. The objects show different emission-line profiles and infrared excesses which are most likely due to different tilt angles of their non-spherical envelopes with respect to the line of sight. Variability of spectral lines is discussed here.
  • Ескіз
    Документ
    The emission-line dusty object IRAS 07080+0605, a less-evolved example of the red rectangle
    (Одеський національний університет імені І. І. Мечникова, 2020) Khokhlov, S. A.; Miroshnichenko, A. S.; Zharikov, S. V.; Manset, N.; Zakhozhay, O. V.; Bilinskyi, I. O.; Grankin, K. N.; Kusakin, A. V.; Omarov, C. T.; Kokumbaeva, R. I.; Reva, I. V.; Korcakova, D.; Usenko, I. A.; Kuratova, A. K.
    The all-sky survey conducted by the InfraRed Astronomical Satellite (IRAS) in the 1980’s discovered many objects with infrared excesses whose nature has not been explored until recently. IRAS 07080+0605 is one of those identified in the visual spectral range with an early-type star, which shows the B[e] phenomenon. The object is puzzling, because it exhibits one of the strongest infrared excesses associated with a star of one of the lowest surface temperatures (8500 K) among ob jects with the B[e] phenomenon, an apparent combination of spectral features of dwarfs and supergiants, and the absence of a surrounding optical nebula. Our photometric and spectroscopic study shows that the ob ject’s properties are similar to those of the famous Red Rectangle proto-planetary nebula. In this paper we describe our findings and hypotheses about the nature and evolutionary status of IRAS 07080+0605.