Ancient dreams : a spectroscopic study of variable stars in binary systems.
| dc.contributor.author | Sekaran, Sanjay | |
| dc.date.accessioned | 2016-05-31T01:33:39Z | |
| dc.date.available | 2016-05-31T01:33:39Z | |
| dc.date.issued | 2016 | en |
| dc.description.abstract | This thesis presents the results of the orbital and asteroseismological analysis of three variable stars in binary systems: HD 182640, a system with a candidate γ Doradus primary; HD 3112, a system with a bona fide δ Scuti primary; and HD 147787, a system with a candidate Doradus primary. Approximately 2500 spectra of all three stars were obtained from the HERCULES spectrograph, attached to the 1-metre telescope at the University of Canterbury Mount John Observatory. The raw spectra were reduced to radial velocity line profiles through cross-correlation with synthetic spectra. Orbital analysis of HD 182640 characterised it as a long period (1256 d) binary with an eccentric orbit (e = 0.43). A total of 18 pulsational frequencies, explaining 42.9% of the variation across the line profiles, were identified. These frequencies were all characterised as high degree ( ℓ; > 4) modes. Orbital analysis of HD3112 characterised it as a short period (7 d) binary with an effectively circular orbit (e = 0.01). A total of 17 pulsational frequencies, explaining 46.3% of the variation across the line profiles, were identified. The mode of the primary pulsation frequency ( ƒ1 = 20.2802 d⁻¹) was the only one that was able to be identified. Previously identified ellipsoidal variations may have hindered mode identification efforts. Orbital analysis of HD 147787 characterised it as a moderate period (40 d) binary with an eccentric orbit (e = 0.25). A total of 9 pulsational frequencies, explaining 48.1% of the variation across the line profiles, were identified. The modes of 6 out of the 9 pulsational frequencies, all low-degree ( ℓ; ≤ 3) modes, were able to be identified. The 3 unidentified frequencies are abnormally low for a γ Doradus star. Previously unidentified ellipsoidal variations may have hindered mode identification efforts. | en |
| dc.identifier.uri | http://hdl.handle.net/10092/12237 | |
| dc.identifier.uri | http://dx.doi.org/10.26021/7364 | |
| dc.language | English | |
| dc.language.iso | en | |
| dc.publisher | University of Canterbury | en |
| dc.rights | All Rights Reserved | en |
| dc.rights.uri | https://canterbury.libguides.com/rights/theses | en |
| dc.title | Ancient dreams : a spectroscopic study of variable stars in binary systems. | en |
| dc.type | Theses / Dissertations | |
| thesis.degree.discipline | Astronomy | en |
| thesis.degree.grantor | University of Canterbury | en |
| thesis.degree.level | Masters | en |
| thesis.degree.name | Master of Science | en |
| uc.bibnumber | 2321933 | |
| uc.college | Faculty of Science | en |