High- and low-resolution spectroscopic observations of the peculiar planetary-nebula HD 149427 (=PC 11)

作者：Pereira C B^*; Baella N O; Daflon S; Miranda L F

来源：Astronomy & Astrophysics, 2010, 509: A13.

DOI：10.1051/0004-6361/200912309

• planetary nebulae: individual: HD 149427
• stars: abundances
• stars: fundamental parameters

Aims. We discuss the status of the A-type component of the binary central star in the peculiar planetary nebula HD 149427.
Methods. We acquired low and high spectral resolution optical spectroscopy for the range 4500-9000 angstrom.
Results. The analysis of the high resolution spectrum shows that the A-type star has an effective temperature of T(eff) = 8700 +/- 150 K and a surface gravity of log g = 2.3 +/- 0.4, corresponding to a spectral type A3-A4 II. These parameters infer a luminosity estimate of log(L/L(circle dot)) = 3.69 +/- 0.32, implying a distance of 10 +/- 0.6 kpc. The A-type star is slightly metal-poor; barium and strontium, two key elements for monitoring the s-process nucleosynthesis, are not enriched; nitrogen is enriched relative to Sun; while carbon and oxygen are underabundant. The photospheric abundance of the A-type giant star in HD 149427 is compared with the abundance in other types of stars at different evolutionary stages.

• 出版日期2010-1