naa a22 4500 510789935 CHVBK 20180411083316.0 cr unu---uuuuu 180411e20130901xx s 000 0 eng 10.1134/S1063773713090016 doi (NATIONALLICENCE)springer-10.1134/S1063773713090016 Nonstationarity of hot post-AGB objects: Variations of the brightness and spectrum of IRAS 01005+7910, IRAS 22023+5249, and IRAS 22495+5134 [Elektronische Daten] [V. Arkhipova, M. Burlak, V. Esipov, N. Ikonnikova, G. Komissarova] UBV photometry for two hot protoplanetary nebula candidates, early B supergiants with emission lines in the spectrum, IRAS 01005+7910 and IRAS 22023+5249, as well as for IRAS 22495+5134, the central star of the young compact planetary nebula M 2-54, is presented for the first time. Fast irregular brightness variations of the stars with maximum amplitudes up to and color-brightness correlations have been found: the B - V colors tend to become redder with increasing brightness, while U - B more likely decrease with brightening. The color excesses E(B - V) have been determined. The equivalent widths and absolute intensities of emission lines have been derived from low-resolution spectroscopy. Spectral variability has been revealed in all objects. The parameters of the gaseous nebula have been calculated for M 2-54: N e ∼ 104 cm−3and T e = 7700 ± 200 K. A joint analysis of the photometric and spectroscopic data suggests that stellar wind variations can be one of the causes of the stellar variability. The luminosities and distances of all three objects have been estimated. Pleiades Publishing, Ltd., 2013 protoplanetary nebulae nationallicence planetary nebulae nationallicence photometric and spectroscopic observations nationallicence brightness variations nationallicence Arkhipova V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Burlak M. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Esipov V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Ikonnikova N. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Komissarova G. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut Astronomy Letters Springer US; http://www.springer-ny.com 39/9(2013-09-01), 619-633 1063-7737 39:9<619 2013 39 11443 https://doi.org/10.1134/S1063773713090016 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1063773713090016 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Arkhipova V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 700 1- Burlak M. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 700 1- Esipov V. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 700 1- Ikonnikova N. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 700 1- Komissarova G. Sternberg Astronomical Institute, Universitetskii pr. 13, 119992, Moscow, Russia aut NATIONALLICENCE 773 0- Astronomy Letters Springer US; http://www.springer-ny.com 39/9(2013-09-01), 619-633 1063-7737 39:9<619 2013 39 11443 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer