Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

Abstract

Based on high-spectral resolution observations performed with the echelle spectrograph NES of the 6-meter telescope, we have studied the peculiarities of the spectrum and the velocity field in the atmosphere and envelope of the optical counterpart of the infrared source IRAS 23304+6347. We have concluded about the absence of significant variations in the radial velocity Vr inferred from atmospheric absorptions and about its coincidence with the systemic velocity deduced from radio data. The envelope expansion velocity Vexp = 15.5 km/s has been determined from the positions of rotational band lines of the C 2 Swan (0; 0) band. A complex emission-absorption profile of the Swan (0; 1) 5635Å has been recorded. Analysis of the multicomponent NaI D doublet line profile has revealed interstellar components V(IS) = −61.6 and −13.2 km/s as well as a circumstellar component with V(CS) =−41.0 km/s whose position corresponds to the velocity inferred from C 2 features. The presence of the interstellar component with Vr =−61.6 km/s in the spectrum allows d = 2.5 kpc to be considered as a lower limit for the distance to the star. A splitting of the profiles for strong absorptions of ionized metals (YII, BaII, LaII, SiII) attributable to the presence of a short-wavelength component originating in the circumstellar envelope has been detected in the optical spectrum of IRAS 23304+6347 for the first time.

New in the optical spectrum and kinematic state of the atmosphere of the variable V1027 Cyg (=IRAS 20004+2955)

“…Thus, evidence for an efficient dredge-up of the heavy metals produced during the preceding evolution of this star into the envelope was obtained. A similar effect was detected (Klochkova et al 2015) in the spectrum of the optically faint star associated with the IR source IRAS 23304+6147, with large overabundances of carbon and heavy metals having been revealed in its atmosphere (Klochkova et al 2000b). The general properties of a sample of post-AGB supergiants with a splitting of strong absorptions are summarized in Klochkova and Panchuk (2016), where it was shown that the type of profiles for strong absorptions could be connected with the morphology of the envelope and with its kinematic and chemical properties.…”

Vertical distribution and kinematics of protoplanetary nebulae in the galaxy

“…At the same time, there are many publications where for individual objects information about their systemic line-of-sight velocities is available. These include, for example, the papers by Klochkova et al (1999Klochkova et al ( , 2007Klochkova et al ( , 2014Klochkova et al ( , 2015, Klochkova Our list contains a total of 147 nebulae (we combined the lists of PPNe and the lists of candidates from the catalogue by Vickers et al (2015)). It contains either only the line-ofsight velocities (55 nebulae), or only the proper motions (25 nebulae), or both line-of-sight velocities and proper motions (67 nebulae).…”

The detection of heavy metals in the circumstellar envelopes of post-AGB stars

“…molecular bands in their IR, radio, and optical spectra. Presence and type of C 2 bands for stars in Table 1 are published by [18][19][20][21]; [22,24,[26][27][28][29].…”

“…Morphology Notes: a -morphology type of envelopes is taken from papers by [3,4,9,10]; b - [11], c - [12], d - [14], e - [15], f - [16], g - [18], h - [22], i - [24], j - [19], k - [20], l - [21], m - [26], n - [27], o - [28], p - [29].…”