Abstract
We have derived the atmospheric parameters of the R CrB carbon star DY Per. The spectrum of DY Per near its maximum brightness was obtained using the 2.6-m ZTSh telescope of the Crimean Astrophysical Observatory, and has a resolution of about 1.74 Å per pixel. We compare the absolute observed and theoretical spectral energy distributions (SEDs) of DY Per for λλ 430–730 nm for the first time. The model atmospheres were computed using a code written by Ya.V. Pavlenko in the classical approximation, taking into account the main opacity sources in carbon-star atmospheres. The theoretical SEDs were computed using the list of atomic lines from the VALD database and the molecular line lists from CD-ROM No. 18 of Kurucz’s database. The estimated by spectral synthesis effective temperature of DY Per is in the range of 2900–3100 K, if we assume log g = 0. We find a metal deficiency in the atmosphere of DY Per. Quantitative estimates of the overall metallicity, carbon and nitrogen abundances, and the H/He ratio are somewhat uncertain: −2 ≤ [Fe/H] ≤ −0.5, 0.65 ≤ [C/Fe] ≤ 1.35, 0.0 ≤ [N/Fe] ≤ 0.8, 1/9 ≤ H/He ≤ 9/1. These high H/He values do not quite agree with qualitative observational estimates made by other authors. Our results confirm that DY Per is a unique stellar object. This is the coolest and possibly the most metal-poor of all known R CrB stars. We conclude that the large deficiencies of metals and hydrogen lead to [C/Fe] values in the atmosphere of DY Per characteristic of R CrB stars.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
C. Hoffmeister, Veroff. Sternw. Sonneberg 1, 1 (1947).
D. Cameron and J. I. Nassau, Astrophys. J. 124, 346 (1956).
A. Alksnis and Z. Jumike, Investig. Sun Red Stars (Riga), 33, 83 (1990).
A. Alksnis, Baltic Astron. 3, 410 (1994).
B. E. Zhilyaev, M. Ya. Orlov, A. F. Pugach et al., RCrB Stars (Naukova Dumka, Kiev, 1978) [in Russian].
A. Weiss, Astron. Astrophys. 187, 178 (1987).
Y. Yamashita, Ann. Tokyo Observ. 15, 47 (1975).
C. A. Dean, Astron. J. 81, 364 (1976).
P. C. Keenan and C. Barnbaum, Publ. Astron. Soc. Pacif. 109, 969 (1997).
A. Bergeat, A. Knapic, and B. Rutily, Astron. Astrophys. 369, 178 (2001).
L. Zacs, W. P. Chen, S. Mondal, et al., Astron. Astrophys. 472, 247 (2007).
A. Alksnis, A. Balklavs, U. Dzervitis, and I. Iglitis, Astron. Astrophys. 338, 209 (1998).
Th. Neckel, Veroff. Landessternw. Heidelberg-Konigstuhl 19, 3 (1967).
M. P. FitzGerald, Astron. J. 73, 983 (1962).
M. J. Reid, Y. Hu, X. W. Zheng, and K. M. Menten, in Proc. of the 207th Meeting of the American Astronomical Society, Washington, DC, 8–12 Jan. 2006 (AAS, 2006), p. 8.
V. G. Metlov, Astron. Astrophys. Trans. 23, 197 (2004).
Ya. V. Pavlenko, Astron. Zh. 80, 67 (2003) [Astron. Rep. 47, 59 (2003)].
R. L. Kurucz, Kurucz CD-Roms, Nos. 1–22 (Smithsonian Astrophys. Observ., Cambridge, MA, USA, 1993–1994).
Ya. V. Pavlenko and S. V. Zhukovskaya, Kinemat. Fiz. Nebesn. Tel 19, 28 (2003).
A. Borisow, U. G. Jorgensen, and C. Zheng, Astron. Astrophys. 324, 185 (1997).
E. A. Gurtovenko and R. I. Kostik, The System of Solar Oscillator Strengths, Preprint MAO-98-3E (Main Astronomical Observatory, Kyiv, 1998).
D. L. Lambert, B. Gustafsson, K. Eriksson, and K.-H. Hinkle, Astrophys. J. Suppl. Ser. 62, 373 (1986).
D. L. Lambert and N. K. Rao, J. Astrophys. Astron. 15, 47 (1994).
M. Asplund, B. Gustafsson, D. L. Lambert, and N. K. Rao, Astron. Astrophys. 353, 287 (2000).
Ya. V. Pavlenko, Astrophys. Space Sci. 253, 43 (1997).
T. Tsuji, Astron. Astrophys. 23, 411 (1973).
R. S. Urdahl, Y. Bao, and W. M. Jackson, Chem. Phys. Lett. 178, 425 (1991).
Y. Huang, S. A. Barts, and J. B. Halpern, J. Phys. Chem. 96, 425 (1992).
P. F. Bernath, J. H. Black, and J. W. Brault, Astrophys. J. 298, 375 (1985).
Ya. V. Pavlenko and A. V. Shavrina, Kinemat. Fiz. Nebesn. Tel 2, 54 (1986).
F. Kupka, N. Piskunov, T. A. Ryabchikova, et al., Astron. Astrophys. Suppl. Ser. 138, 119 (1999).
L. A. Yakovina and Ya. V. Pavlenko, Kinemat. Fiz. Nebesn. Tel 18, 99 (2002).
L. A. Kuznetsova and A. V. Shavrina, Kinemat. Fiz. Nebesn. Tel 12, 75 (1996).
L. A. Kuznetsova, E. A. Pazyuk, and A. V. Stolyarov, in IAU Coll. No. 146: Molecular Opacities in the Stellar Environment, Ed. by P. Thejll and U. G. Jorgensen (Niels Bohr Inst., Copenhagen 1993), p. 63.
L. S. Lyubimkov, Chemical Composition of Stars: Method and Results of Analysis (Astroprint, Odessa, 1995), p. 199 [in Russian].
C. I. Short and J. B. Lester, Astrophys. J. 436, L165 (1994).
L. A. Yakovina and Ya. V. Pavlenko, Kinemat. Fiz. Nebesn. Tel 14, 257 (1998).
Author information
Authors and Affiliations
Additional information
Original Russian Text © L.A. Yakovina, A.F. Pugach, Ya.V. Pavlenko, 2009, published in Astronomicheskiĭ Zhurnal, 2009, Vol. 86, No. 3, pp. 211–227.
Rights and permissions
About this article
Cite this article
Yakovina, L.A., Pugach, A.F. & Pavlenko, Y.V. DY Persei, the coolest metal-poor R CrB carbon star. Astron. Rep. 53, 187–202 (2009). https://doi.org/10.1134/S1063772909030019
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063772909030019