Optical spectra of five UX Orionis-type stars

Abstract

Abstract. We present in this paper several high resolution (R = 27 000) spectra of five UXORs (UX Ori, CQ Tau, BF Ori, RR Tau, WW Vul), which cover the entire visual range, from 3900 to about 8700Å. There are between 4 and 7 spectra per star, obtained over a time interval of two years. Simultaneous or quasi-simultaneous photometric observations were also obtained at the Crimean Astrophysical Observatory. The complete, reduced and normalized spectra are available in electronic form. We show for each star a selection of the most interesting lines, and the full spectrum of UX Ori computed by averaging the spectra obtained when the star was at maximum light. For UX Ori we show also the synthetic spectrum and provide an identification of most of the lines. The spectra are too sparse to form true time sequences; however, they provide an extremely useful database for studies of UX Ori-type stars. We discuss briefly the main features of the spectra. We show that they contain many time-stable photospheric lines that can be described to a good approximation by the synthetic spectra of normal A stars with log g = 3.5−4 and we derive for each star effective temperature, gravity and rotational velocity. We examine the time variability of selected lines and study their connection with the photometric activity of the stars. Two different types of spectral variability are identified. One is common to all stars with circumstellar (CS) gas and is caused by perturbations of the physical and kinematic conditions of the emitting region. There is no correlation between this type of activity and the brightness variations of the star. On the contrary, a second type of spectral variability correlates well with the brightness variations and is very likely connected with the screening effect of an opaque dust cloud which sporadically intersects the line of sight. This type of variability has been observed in its simplest form in one of the RR Tau spectra, where the equivalent width of the forbidden line [O i] 6364Å increased by a factor of about three as the star faded by approximately the same amount.

A dynamical study of the circumstellar gas in UX Orionis

“…They are also observed in many other lines (e.g. He , Fe  and Fe ), as already pointed out by Grinin et al (2001), but a corresponding discussion is deferred to a future work.…”

Hydrogen lines as a diagnostic tool for studying multicomponent emitting regions in hot young stars: magnetosphere, X-wind, and disk wind

“…All kinds of shapes from the classification by Reipurth et al are observed: P Cygni, single-and doublepeaked (see, e.g., Böhm & Catala 1995;Grinin et al 2001;Mora et al 2001;Feigelson et al 2003;Beskrovnaya & Pogodin 2004;Movsessian et al 2008;Grady et al 2011;Montesinos 2009;Mendigutía 2012). Such a vast sample of profile shapes suggests that this line originates in a very complex environment possibly including the accretion disk, disk wind, jet, and magnetosphere.…”

“…Observations of Herbig Ae/Be stars (e.g., Finkenzeller & Mundt 1984;Reipurth et al 1996;Drew et al 1997;Grinin et al 2001) reveal very wide Balmer lines in the spectra of some stars. For optically thick lines such as Hα, Stark broadening can cause the observed line widths.…”

Modeling of PMS Ae/Fe stars using UV spectra

“…Then the distance of the star could be varied within the margins of its uncertainty, implying a corresponding variation of A cs v , which should be limited to positive values. We then varied the inclination angle i of the disc and the extinction law R cs in order to improve the agreement in the Finkenzeller (1985) 11: Walter et al (1987) 20: Martin (1993 29: Meeus et al (1998) 38: Hartmann et al (1989) 3: Hillenbrand et al (1992) 12: Grady et al (1996 21: Bessel & Eggen (1972) 30: Sylvester et al (1996 39: Elias (1978b) 4: Slettebak (1982 13: Herbig & Bell (1988) Shevchenko et al (1997) 15: Herbertz et al (1991 24: Artyukhina (1960) 33: Beskrovnaya et al (1999) 42: Appendix C.41 7: Joncour et al (1994) 16: Friedemann et al (1993) 25: Fernández et al (1995) 34: Glagolevskii et al (1998 43: Appendix C.43 8: Herbig (1966) 17: Finkenzeller & Mundt (1984) 26: Reipurth et al (1996) 35: Wallenquist (1937 44: Mora et al (2001) 9: Andersen et al (1989 18: Kolotilov & Zajtseva (1974) 27: Pérez et al (2004) 36: v.d.Ancker et al (2000 45: Grinin et al (2001) LW (λ > 2000 Å) spectral range. After that M v , δ bl , and R cs were slightly adjusted until the match was optimal.…”