Magnetic activity, differential rotation, and dynamo action in the pulsating F9IV star KIC 5955122

被引:10
作者
Bonanno, A. [1 ]
Froehlich, H. -E. [2 ]
Karoff, C. [3 ,4 ]
Lund, M. N. [3 ]
Corsaro, E. [1 ,5 ]
Frasca, A. [1 ]
机构
[1] Osserv Astrofis Catania, INAF, I-95123 Catania, Italy
[2] Leibniz Inst Astrophys Potsdam AIP, D-14482 Potsdam, Germany
[3] Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, DK-8000 Aarhus C, Denmark
[4] Aarhus Univ, Dept Geosci, DK-8000 Aarhus C, Denmark
[5] Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Leuven, Belgium
基金
欧洲研究理事会; 新加坡国家研究基金会;
关键词
starspots; stars: rotation; stars: magnetic field; magnetohydrodynamics (MHD); stars: individual: KIC 5955122 stars: activity; SUN-LIKE STAR; MERIDIONAL CIRCULATION; MAIN-SEQUENCE; SOLAR DYNAMO; KEPLER; MODEL; CONVECTION; CYCLE; ZONE; FLOW;
D O I
10.1051/0004-6361/201424371
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present photometric spot modeling of the nearly four-year long light-curve of the Kepler target KIC 5955122 in terms of persisting dark circular surface features. With a Bayesian technique, we produced a plausible surface map that shows dozens of small spots. After some artifacts are removed, the residuals are at +/- 0.16 mmag. The shortest rotational period found is P = 16.4 +/- 0.2 days. The equator-to-pole extrapolated differential rotation is 0.25 +/- 0.02 rad/d. The spots are roughly half as bright as the unperturbed stellar photosphere. Spot latitudes are restricted to the zone +/- 60 degrees latitude. There is no indication for any near-pole spots. In addition, the p-mode pulsations enabled us to determine the evolutionary status of the star, the extension of the convective zone, and its radius and mass. We discuss the possibility that the clear signature of active regions in the light curve of the F9IV star KIC 5955122 is produced by a flux-transport dynamo action at the base of the convection zone. In particular, we argue that this star has evolved from an active to a quiet status during the Q0-Q16 period of observation, and we predict, according to our dynamo model, that the characteristic activity cycle is of the order of the solar one.
引用
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页数:9
相关论文
共 43 条
  • [1] [Anonymous], 2007, Numerical Recipes
  • [2] Oscillation mode frequencies of 61 main-sequence and subgiant stars observed by Kepler
    Appourchaux, T.
    Chaplin, W. J.
    Garcia, R. A.
    Gruberbauer, M.
    Verner, G. A.
    Antia, H. M.
    Benomar, O.
    Campante, T. L.
    Davies, G. R.
    Deheuvels, S.
    Handberg, R.
    Hekker, S.
    Howe, R.
    Regulo, C.
    Salabert, D.
    Bedding, T. R.
    White, T. R.
    Ballot, J.
    Mathur, S.
    Aguirre, V. Silva
    Elsworth, Y. P.
    Basu, S.
    Gilliland, R. L.
    Christensen-Dalsgaard, J.
    Kjeldsen, H.
    Uddin, K.
    Stumpe, M. C.
    Barclay, T.
    [J]. ASTRONOMY & ASTROPHYSICS, 2012, 543
  • [3] DYNAMO ACTION AND MAGNETIC CYCLES IN F-TYPE STARS
    Augustson, Kyle C.
    Brun, Allan Sacha
    Toomre, Juri
    [J]. ASTROPHYSICAL JOURNAL, 2013, 777 (02)
  • [4] Baglin A., 2006, 36th COSPAR Scientific Assembly, V36, P3749
  • [5] CHROMOSPHERIC VARIATIONS IN MAIN-SEQUENCE STARS .2.
    BALIUNAS, SL
    DONAHUE, RA
    SOON, WH
    HORNE, JH
    FRAZER, J
    WOODARDEKLUND, L
    BRADFORD, M
    RAO, LM
    WILSON, OC
    ZHANG, Q
    BENNETT, W
    BRIGGS, J
    CARROLL, SM
    DUNCAN, DK
    FIGUEROA, D
    LANNING, HH
    MISCH, A
    MUELLER, J
    NOYES, RW
    POPPE, D
    PORTER, AC
    ROBINSON, CR
    RUSSELL, J
    SHELTON, JC
    SOYUMER, T
    VAUGHAN, AH
    WHITNEY, JH
    [J]. ASTROPHYSICAL JOURNAL, 1995, 438 (01) : 269 - 287
  • [6] ROLE OF ASYMMETRIC MERIDIONAL CIRCULATION IN PRODUCING NORTH-SOUTH ASYMMETRY IN A SOLAR CYCLE DYNAMO MODEL
    Belucz, Bernadett
    Dikpati, Mausumi
    [J]. ASTROPHYSICAL JOURNAL, 2013, 779 (01)
  • [7] Parity properties of an advection-dominated solar α2Ω-dynamo
    Bonanno, A
    Elstner, D
    Rüdiger, G
    Belvedere, G
    [J]. ASTRONOMY & ASTROPHYSICS, 2002, 390 (02) : 673 - 680
  • [8] The age of the Sun and the relativistic corrections in the EOS
    Bonanno, A
    Schlattl, H
    Paternò, L
    [J]. ASTRONOMY & ASTROPHYSICS, 2002, 390 (03) : 1115 - 1118
  • [9] Solar Dynamo and Toroidal Field Instabilities
    Bonanno, Alfio
    [J]. SOLAR PHYSICS, 2013, 287 (1-2) : 185 - 196
  • [10] An overshoot solar dynamo with a strong return meridional flow
    Bonanno, Alfio
    [J]. GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS, 2013, 107 (1-2) : 11 - 19