Open Astronomy (Mar 2003)
High Precision with the Whole Earth Telescope: Lessons and Some Results from XCov20 for the roAp Star HR 1217
- Kurtz D. W.,
- Kawaler S.D.,
- Riddle R. L.,
- Reed M.D.,
- Cunha M. S.,
- Wood M.,
- Silvestri N.,
- Watson T.K.,
- Dolez N.,
- Moskalik P.,
- Zola S.,
- Pallier E.,
- Guzik J.A.,
- Metcalfe T. S.,
- Mukadam A.,
- Nather R.E.,
- Winget D.E.,
- Sullivan D. J.,
- Sullivan T.,
- Sekiguchi K.,
- Jiang X.J.,
- Shobbrook R.R.,
- Birch P.V.,
- Ashoka B. N.,
- Seetha S.,
- Joshi S.,
- Girish V.,
- O’Donoghue D.,
- Handler G.,
- Mueller M.,
- Perez J.M. Gonzalez,
- Solheim J.-E.,
- Johannessen F.,
- Ulla A.,
- Kepler S.O.,
- Kanaan A.,
- Costa A.da,
- Fraga L.,
- Giovannini O.,
- Matthews J. M.,
- Cameron C.,
- Vauclair G.,
- Nitta A.,
- Kleinman S. J.
Affiliations
- Kurtz D. W.
- Centre for Astrophysics, University of Central Lancashire, Preston PR1 2HE, UK South Africa
- Kawaler S.D.
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, United States of America
- Riddle R. L.
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, United States of America
- Reed M.D.
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, U.S.A. Chile
- Cunha M. S.
- Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal Portugal
- Wood M.
- Department of Physics & Space Sciences and SARA Observatory, Florida Institute of Technology, Melbourne, FL, United States of America
- Silvestri N.
- Department of Physics & Space Sciences and SARA Observatory, Florida Institute of Technology, Melbourne, FL, United States of America
- Watson T.K.
- Southwestern University, 1001 E. University Avenue, Georgetown, TX, United States of America
- Dolez N.
- Observatoire Midi-Pyrénées, CNRS/UMR5572, 14 av. E. Belin, 31400 Toulouse, France
- Moskalik P.
- Nicolas Copernicus Astronomical Centre, ul. Bartycka 18, 00-716 Warsaw, Poland
- Zola S.
- Kraków Pedagogical University, ul. Podchorążych 2, Krakow, Poland
- Pallier E.
- Observatoire Midi-Pyrénées, CNRS/UMR5572, 14 av. E. Belin, 31400 Toulouse, France
- Guzik J.A.
- X-2, MS T085, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
- Metcalfe T. S.
- McDonald Observatory, and Department of Astronomy, University of Texas, Austin, TX 78712, United States of America
- Mukadam A.
- McDonald Observatory, and Department of Astronomy, University of Texas, Austin, TX 78712, United States of America
- Nather R.E.
- McDonald Observatory, and Department of Astronomy, University of Texas, Austin, TX 78712, United States of America
- Winget D.E.
- McDonald Observatory, and Department of Astronomy, University of Texas, Austin, TX 78712, United States of America
- Sullivan D. J.
- School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
- Sullivan T.
- School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
- Sekiguchi K.
- Subaru Observatory, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720, United States of America
- Jiang X.J.
- National Astronomical Observatories and Joint Laboratory of Optical Astronomy, Chinese Academy of Sciences, Beijing, 100012, China
- Shobbrook R.R.
- Research School of Astronomy & Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611, Australia
- Birch P.V.
- Perth Observatory, Walnut Rd, Bickley, Western Australia 6076, Australia
- Ashoka B. N.
- Indian Space Research Organization, Vimanapura PO, Bangalore 560 017, India
- Seetha S.
- Indian Space Research Organization, Vimanapura PO, Bangalore 560 017, India
- Joshi S.
- State Observatory, Manora Peak, Naini Tal 263 129, India
- Girish V.
- Indian Space Research Organization, Vimanapura PO, Bangalore 560 017, India
- O’Donoghue D.
- South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa
- Handler G.
- South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa
- Mueller M.
- Department of Astronomy, University of Cape Town, Rondebosch 7701, South Africa
- Perez J.M. Gonzalez
- Department of Physics, University of Tromso, N-9037 Tromso, Norway
- Solheim J.-E.
- Department of Physics, University of Tromso, N-9037 Tromso, Norway
- Johannessen F.
- Department of Physics, University of Tromso, N-9037 Tromso, Norway
- Ulla A.
- Depto. de Fisica Aplicada, Universidade de Vigo, 36200 Vigo, Spain
- Kepler S.O.
- Instituto de Fisica, UFRGS, Campus do Vale, C.P. 15051, Porto Alegre, RS, Brazil
- Kanaan A.
- Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Costa A.da
- Instituto de Fisica, UFRGS, Campus do Vale, C.P. 15051, Porto Alegre, RS, Brazil
- Fraga L.
- Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Giovannini O.
- Departamento de Física e Química, Universidade de Caxias do Sul, 95001-970 Caxias do Sul, RS, Brazil
- Matthews J. M.
- Dept. of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Cameron C.
- Dept. of Physics and Astronomy, University of British Columbia, Vancouver, Canada
- Vauclair G.
- Observatoire Midi-Pyrénées, CNRS/UMR5572, 14 av. E. Belin, 31400 Toulouse, France
- Nitta A.
- Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, United States of America
- Kleinman S. J.
- Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, United States of America
- DOI
- https://doi.org/10.1515/astro-2017-0036
- Journal volume & issue
-
Vol. 12,
no. 1
pp. 105 – 117
Abstract
HR1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of nonradial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 μHz and 34.6 μHz, with a sixth mode at a problematic spacing of 50.0 μHz (which equals 1.5 × 33.3 μHz) to the highfrequency side. Asymptotic pulsation theory allowed for a frequency spacing of 34 μHz, but hipparcos observations rule out such a spacing. Theoretical calculations of magnetoacoustic modes in Ap stars by Cunha (2001) predicted that there should be a previously undetected mode 34 μHz higher than the main group, with a smaller spacing between it and the highest one. The 20th extended coverage campaign of the Whole Earth Telescope (XCov20) has discovered this frequency as predicted by Cunha (2001). Amplitude modulation of several of the pulsation modes between the 1986 and 2000 data sets has also been discovered, while important parameters for modelling the geometry of the pulsation modes have been shown to be unchanged. With stringent selection of the best data from the WET network the amplitude spectrum shows highest peaks at only 50 μmag and formal errors on the determined amplitudes are 14 μmag. Some lessons for future use of WET for the highest precision photometry on bright stars are discussed.
Keywords
