The field high-amplitude SX Phoenicis variable BL Camelopardalis: results from a multisite photometric campaign. I. Pulsation
- Creators
- Rodríguez, E.
- Fauvaud, S.
- Farrell, J. A.
- Zhou, A.-Y.
- Sareyan, Jean-Pierre
- López-González, M. J.
- Dupret, Marc-Antoine
- Grigahcène, A.
- de Ridder, Joris
- Klingenberg, G.
- Wolf, M.
- van Cauteren, P.
- Lampens, P.
- Martínez, D.
- Casanova, V. M.
- Aceituno, F. J.
- Helvaci, M.
- Hintz, E. G.
- Král, L.
- Fumagalli, F.
- Simonetti, J. H.
- Granslo, B. H.
- Kotková, L.
- Santacana, G.
- Michelet, J.
- Fauvaud, M.
- Vugnon, J.-M.
- Sadsaoud, H.
- Aliouane, S.
- Grigahcéne, Z. C.
- Martin-Ruiz, Susana
- Amado, Pedro J.
- Suárez, Juan Carlos
- Moya, Andrés
- Kucáková, H.
- Kocián, R.
- Truparová, K.
- Avdibegovic, A.
- Blazek, M.
- Kliner, J.
- Zasche, P.
- Vilásek, M.
- Bartosíková, S.
- Yasarsoy, B.
- Ulusoy, C.
- Graham, K. A.
- Nicholson, M. P.
- Trondal, O.
- Yesilyaprak, C.
- Coker, D.
- Others:
- Instituto de Astrofisica de Andalucia, CSIC (IAA)
- Association AstroQueyras ; Association AstroQueyras
- Groupe européen d'observation stellaire (GEOS)
- Sulphur Flats Observatory
- National Astronomical Observatoires-CAS
- Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
- Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
- Pôle Astronomie du LESIA ; Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris ; Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
- Centre de Recherche en Astronomie Astrophysique et Géophysique - Observatoire d'Alger (CRAAG)
- Instituut voor Sterrenkunde, Katholieke Universiteit Leuven
- Variable Star Section, Norwegian Astronomical Society
- Astronomical Institute, Charles University
- Beersel Hills Observatory
- Koninklijke Sterrenwacht van België
- Department of Astronomy and Space Sciences, Ankara University
- Department of Physics and Astronomy, Brigham Young University
- Observatory and Planetarium of Johann Palisa, VSB - Technical University
- Martin Observatory, Physics Dep., Virginia Polytechnic Institute & State University, Blacksburg
- Astronomical Institute, Academy of Sciences
- Club d'Astronomie Lyon Ampéré [Vaulx-en-Velin] (CALA)
- Club Eclipse : Club d'Etudes du Ciel, de la Lune, des Instruments, des Planètes, du Soleil et des Etoiles...
- Ege University Observatory
- American Association of Variable Star Observers (AAVSO)
- Department of Physics, Akdeniz University
Description
Context: BL Cam is an extreme metal-deficient field high-amplitude SX Phe-type variable where a very complex frequency spectrum is detected, with a number of independent nonradial modes excited, unusual among the high-amplitude pulsators in the Lower Classical Instability Strip.
Aims: An extensive and detailed study has been carried out to investigate the pulsational content and properties of this object.
Methods: The analysis is based on 283 h of CCD observations obtained in the Johnson V filter, during a long multisite photometric campaign carried out along the Northern autumn-winter of 2005-2006. Additionally, multicolour BI photometry was also collected to study the phase shifts and amplitude ratios, between light curves obtained in different filters, for modal discrimination of the main excited modes.
Results: The detailed frequency analysis revealed a very rich and dense pulsational content consisting of 25 significant peaks, 22 of them corresponding to independent modes: one is the already known main periodicity f0 = 25.5765 cd-1 (Delta V = 153 mmag) and the other 21 are excited modes showing very small amplitudes. Some additional periodicities are probably still remaining in the residuals. This represents the most complex spectrum ever detected in a high-amplitude pulsator of this type. The majority of the secondary modes suspected from earlier works are confirmed here and, additionally, a large number of new peaks are detected. The amplitude of the main periodicity f0 seems to be stable during decades, but the majority of the secondary modes show strong amplitude changes from one epoch to another. The suspected fundamental radial nature of the main periodicity of BL Cam is confirmed, while the secondary peak f1 = 25.2523 cd-1 is identified as a nonradial mixed mode g4 with l = 1. The radial double-mode nature, claimed by some authors for the main two frequencies of BL Cam, is not confirmed. Nevertheless, the frequency f6 = 32.6464 cd-1 could correspond to the first radial overtone.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-03733398
- URN
- urn:oai:HAL:hal-03733398v1
- Origin repository
- UNICA