Discovery of spectral variation in the optical counterpart of IRAS 01005+7910

¹ Special Astrophysical Observatory of the Russian Academy of Sciences, Karachai-Cirkassian Republic, Nizhnij Arkhyz 369167, Russia
² Isaac Newton Institute of Chile, SAO Branch
³ Ritter Observatory, Dept. of Physics & Astronomy, University of Toledo, Toledo, OH 43606-3390, USA
⁴ Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140 Saint-Petersburg, Russia

Corresponding author: V. G. Klochkova, valenta@sao.ru

Received: 1 March 2002
Accepted: 29 May 2002

Abstract

We present a study of the high-resolution spectroscopic data for the proto-planetary nebula candidate IRAS 01005+7910. For the first time a careful spectral line identification is carried out, and a significant variability of the optical spectrum is detected. We found absorption lines of C ii/iii, N ii, O ii, Al iii, Si iii, and Mg ii ( Å), as well as emission lines of Si ii and [Fe ii]. Both absorption and emission components are present in the Balmer lines, Na i resonance D lines, He i, and Fe iii lines. The He i line profiles vary from straight to inverse P Cyg-type on a timescale of days to months. The resonance Na i lines show 5 absorption components at a resolution of . Additionally, the Na i D₂ line exhibits a variable emission component with a width comparable to that of the Balmer line emission components. Using the model atmospheres method within the LTE-approximation, the effective temperature ( K), the metallicity , and the ratio is reported. Finally, we suggest that IRAS 01005+7910 is a carbon-rich post-AGB star with a luminosity at a distance about 3 kpc.