Abstract
Chemical peculiar Ap stars show overabundances of
some metals, such as strontium, chromium, europium, praseodymium, and
neodymium. The rotations of these stars are much slower than those of normal
A-type stars. Another characteristic of Ap stars is that they have stronger
magnetic fields compared to classical A-type stars. We have selected the A-type
stars HD 90763 and HD 92728 to derive their atmospheric parameters. Both stars'
high-resolution spectra were obtained using the Coude Echelle Spectrograph
mounted on the 1.5 m Russian-Turkish Telescope at the TÜBİTAK National
Observatory, on the 23rd of February, 2017. The wavelength range of
the spectra is from 3900 to 7900 Å. We followed the standard reduction
procedures for both stars and normalised the order covering the hydrogen beta
profile. We used ATLAS9 model atmospheres. The strontium 4215.519 Å line seen
in the spectra of HD 90763 and the neodymium 5102.428
Å line of HD 92728 were compared to the same lines of the normal A-type
star HD 187983. Sr line in HD 90763 and Nd line in HD 92728 are much stronger
than those of the normal A-type star. Thus, we suggest that HD 90763 and HD
92728 may be chemically peculiar Ap star candidates.
References
- Cowley, A., Cowley, C., Jaschek, M., Jaschek, C. (1969). A study of the bright A stars. I. A catalogue of spectral classifications. Astronomical Journal, 74, 375- 406. Hog E., Fabricıus C., Makarov V.V., Urban S., Corbın T., Wycoff G., Bastıan U., Schwekendıek P., Wıcenec A. (2000). The Tycho-2 catalogue of the 2.5 million brightest stars. Astronomy and Astrophysics, 355, 27-30. Kurucz, R. L. (1993a). ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. Kurucz CD-ROM No. 13. Cambridge, Mass.: Smithsonian Astrophysical Observatory, 1993. Kurucz, R. L. (1993b). SYNTHE Spectrum Synthesis Programs and Line Data. Kurucz CD-ROM No. 18. Cambridge, Mass.: Smithsonian Astrophysical Observatory, 1993. Kurucz, R.L., (2005). ATLAS12, SYNTHE, ATLAS9, WIDTH9, et cetera. Mem. Soc. Astron. Ital. Suppl. 8, 14 Martin, J.C. (2004). The Origins and Evolutionary Status of B Stars Found Far from the Galactic Plane. I. Composition and Spectral Features. The Astronomical Journal, 128, 2474-2500. McDonald, I., Zıjlstra A.A., Boyer M.L. (2012). Fundamental parameters and infrared excesses of Hipparcos stars. Monthly Notices of the Royal Astronomical Society, 427, 343-357. Napiwotzki, R., Schoenberner, D., Wenske, V. (1993). On the determination of effective temperature and surface gravity of B, A, and F stars using Stromgren UVBY beta photometry. Astronomy and Astrophysics, 268, 653-666. Sbordone, L., Bonifacio, P., Castelli, F., Kurucz, R. L. (2004). ATLAS and SYNTHE under Linux. Memorie della Società Astronomica Italiana Supplement, 5, 93.
Abstract
References
- Cowley, A., Cowley, C., Jaschek, M., Jaschek, C. (1969). A study of the bright A stars. I. A catalogue of spectral classifications. Astronomical Journal, 74, 375- 406. Hog E., Fabricıus C., Makarov V.V., Urban S., Corbın T., Wycoff G., Bastıan U., Schwekendıek P., Wıcenec A. (2000). The Tycho-2 catalogue of the 2.5 million brightest stars. Astronomy and Astrophysics, 355, 27-30. Kurucz, R. L. (1993a). ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. Kurucz CD-ROM No. 13. Cambridge, Mass.: Smithsonian Astrophysical Observatory, 1993. Kurucz, R. L. (1993b). SYNTHE Spectrum Synthesis Programs and Line Data. Kurucz CD-ROM No. 18. Cambridge, Mass.: Smithsonian Astrophysical Observatory, 1993. Kurucz, R.L., (2005). ATLAS12, SYNTHE, ATLAS9, WIDTH9, et cetera. Mem. Soc. Astron. Ital. Suppl. 8, 14 Martin, J.C. (2004). The Origins and Evolutionary Status of B Stars Found Far from the Galactic Plane. I. Composition and Spectral Features. The Astronomical Journal, 128, 2474-2500. McDonald, I., Zıjlstra A.A., Boyer M.L. (2012). Fundamental parameters and infrared excesses of Hipparcos stars. Monthly Notices of the Royal Astronomical Society, 427, 343-357. Napiwotzki, R., Schoenberner, D., Wenske, V. (1993). On the determination of effective temperature and surface gravity of B, A, and F stars using Stromgren UVBY beta photometry. Astronomy and Astrophysics, 268, 653-666. Sbordone, L., Bonifacio, P., Castelli, F., Kurucz, R. L. (2004). ATLAS and SYNTHE under Linux. Memorie della Società Astronomica Italiana Supplement, 5, 93.
Details
| Primary Language | English |
|---|---|
| Journal Section | Articles |
| Authors | |
| Publication Date | August 19, 2018 |
| Published in Issue | Year 2018Issue: 2 |
