The pulsating ? Bootis star 15 Andromedae: results from a three-site photometry campaign
- Author(s)
- Tatyana N Dorokhova, Gerald Handler
- Abstract
Context: The ? Bootis stars are a chemically peculiar subgroup of main sequence A/F stars. Several of these fall into the instability strip of the ? Scuti stars and the whole spectroscopic group shows a high incidence of pulsational variability. Aims: We investigated the pulsational behaviour of the ? Bootis star 15 And (HD 221756) to determine as many intrinsic mode frequencies as possible for asteroseismic applications. Methods: The star was included as a secondary target for three telescopes during a campaign devoted to the ? Cep stars 12 and 16 Lac, due to its proximity to these targets. 302.8 h of time-resolved photometry spanning 161.2 d were acquired and analyzed. Results: Our frequency analysis revealed f1 = 24.7887(2) c/d as the main pulsation frequency, with an amplitude of only 1.9(1) mmag. The residual periodogram suggests the presence of additional frequencies in an interval from 20 to 25 c/d, with very low amplitudes. We succeeded in detecting a second frequency f2 = 22.2580(9) with an amplitude of 0.6(1) mmag. Low-frequency light variations of the comparison star HD 220575 were revealed as well. Conclusions: The pulsational behaviour of 15 And as a typical ? Boo-type star is compared with that of ? Scuti stars with normal abundances and with metallic-line ? Scuti stars. We discuss the value of ? Boo stars in understanding accretion and mixing in pulsating stars. The difficulties in the selection of reliable comparison stars for such high-precision research are pointed out.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Odessa Astronomical Observatory
- Journal
- Astronomy & Astrophysics
- Volume
- 480
- Pages
- 187-191
- No. of pages
- 5
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361:20078750
- Publication date
- 2008
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/8dc5ab9f-a4c1-409a-af03-b5501c2b4bc4