30+ frequencies for the d Scuti variable 4 Canum Venaticorum: Results of the 1996 multisite campaign

Autor(en)

Michel Breger, Gerald Handler, Rafael Garrido, N Audard, Wolfgang Zima, Margit Paparó, Fritz Beichbuchner, Zhi Ping Li, Shi Yang Jiang, Zong L Liu, Ai Ying Zhou, Holger Pikall, Anamarija Stankov, Joyce Ann Guzik, J Krzesinski, W Ogloza, G Pajdosz, S Zola, T Thomassen, Jan Erik Solheim, E Serkowitsch, Peter Reegen, T Rumpf, Alois Schmalwieser, Michael H. Montgomery

Abstrakt

The evolved d Scuti variable 4 CVn was observed photometrically for 53 nights on three continents. We found a total of 34 significant and 1 probable simultaneously excited frequencies. Of these, 16 can be identified as linear combinations of other frequencies. All significant frequencies outside the 4.5 to 10 cd-1 (52 to 116 œHz) range can be identified with frequency combinations, fi ‘fi, of other modes with generally high amplitudes. There exists a number of closely spaced frequencies with separations of ~ 0.06 cd-1. This cannot be explained in terms of amplitude variability. The results show that even for stars on and above the main sequence other than the Sun, a very large number of simultaneously excited nonradial oscillations can be detected by conventional means. Since all pulsation modes with photometric amplitudes of 1 mmag or larger have now been detected for this star, a presently unknown mode selection mechanism must exist to select between the 1000+ of low-degree modes predicted to be excited for this (and many other) stars. Phase differences and amplitude ratios between the y and ? colors are determined for the ten main modes. The phase differences indicate p1 to p4 modes of l = 1 for four of these modes. The formulae to determine the uncertainties in the amplitudes and phases of sinusoidal fits to observational data are derived in the Appendix.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Instituto de Astrofísica de Andalucía, Université Côte d'Azur, Hungarian Academy of Sciences, University of Science and Technology Beijing, Chinese Academy of Sciences (CAS), Los Alamos National Laboratory, Pedagogical University of Cracow, University of Tromsø - The Arctic University of Norway, University of Texas, Austin, Jagiellonian University in Krakow

Journal

Astronomy & Astrophysics

Band

349

Seiten

225-235

Anzahl der Seiten

11

ISSN

0004-6361

Publikationsdatum

1999

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/30-frequencies-for-the-d-scuti-variable-4-canum-venaticorum-results-of-the-1996-multisite-campaign(adf7e6ce-4ebf-4416-89e5-e444bf38a9f5).html