2013A&A...559A.119L


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.08CEST03:10:17

2013A&A...559A.119L - Astronomy and Astrophysics, volume 559A, 119-119 (2013/11-1)

X-ray activity cycle on the active ultra-fast rotator AB Doradus A? Implication of correlated coronal and photometric variability.

LALITHA S. and SCHMITT J.H.M.M.

Abstract (from CDS):

Although chromospheric activity cycles have been studied in a larger number of late-type stars for quite some time, very little is known about coronal activity-cycles in other stars and their similarities or dissimilarities with the solar activity cycle. While it is usually assumed that cyclic activity is present only in stars of low to moderate activity, we investigate whether the ultra-fast rotator AB Dor, a K dwarf exhibiting signs of substantial magnetic activity in essentially all wavelength bands, exhibits an X-ray activity cycle in analogy to its photospheric activity cycle of about 17 years and possible correlations between these bands. We analysed the combined optical photometric data of AB Dor A, which span ∼35 years. Additionally, we used ROSAT and XMM-Newton X-ray observations of AB Dor A to study the long-term evolution of magnetic activity in this active K dwarf over nearly three decades and searched for X-ray activity cycles and related photometric brightness changes. AB Dor A exhibits photometric brightness variations ranging between 6.75<Vmag≤7.15 while the X-ray luminosities range between 29.8<logLX[erg/s]≤30.2 in the 0.3-2.5keV. As a very active star, AB Dor A shows frequent X-ray flaring, but in the long XMM-Newton observations a kind of basal state is attained very often. This basal state probably varies with the photospheric activity-cycle of AB Dor A, which has a period of ∼17 years, but the X-ray variability amounts at most to a factor of ∼2, which is, much lower than the typical cycle amplitudes found on the Sun.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: coronae - stars: late-type - stars: individual: AB Dor

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 StKM 1-258 RS* 02 22 25.8545367826 +47 29 19.820161314   12.67 11.57     M0 22 0
2 * iot Hor PM* 02 42 33.4664838826 -50 48 01.056222150   5.97 5.40     F8V 340 1
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14826 1
4 HD 36705B ** 05 28 44.4833327579 -65 26 46.034324029     13.0     M5+M5-6 87 0
5 ** RST 137 ** 05 28 44.78 -65 26 56.2           ~ 8 1
6 HD 36705C * 05 28 44.83 -65 26 54.9           M8: 58 1
7 HD 36705 TT* 05 28 44.8916324761 -65 26 55.289846904 8.259 7.856 6.999 6.496 5.993 K0V 931 0
8 TYC 3377-296-1 RS* 06 41 16.7655042855 +46 49 08.968788836   13.16 12.32     ~ 10 0
9 HD 81089 * 09 23 03.7702718336 -21 56 18.091855746   10.23 8.62     M2/3III 3 0
10 HD 81809 SB* 09 27 46.77993 -06 04 16.2822   6.02 5.40     G1.5IV-V 272 0
11 * tau Boo Ro* 13 47 15.74340 +17 27 24.8552 5.02 4.98 4.49 4.09 3.85 F7IV-V 880 1
12 * alf Cen ** 14 39 29.71993 -60 49 55.9990   0.4 -0.1     G2V+K1V 817 0
13 * alf Cen B PM* 14 39 35.06311 -60 50 15.0992 2.89 2.21 1.33     K1V 894 1
14 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1138 0
15 V* V505 Ser bL* 16 02 48.2246171758 +25 20 38.219613334   11.47 10.552 10.16 9.479 ~ 37 1
16 V* EY Dra BY* 18 16 16.7813769184 +54 10 21.761728162   13.69 11.84     dM1.5e 67 0
17 * 61 Cyg A BY* 21 06 53.9396100677 +38 44 57.897024357 7.50 6.39 5.21 4.19 3.54 K5V 945 0
18 * 61 Cyg ** 21 06 53.95 +38 44 57.9           ~ 158 0
19 * 61 Cyg B Fl* 21 06 55.2640651855 +38 44 31.362140913 8.63 7.40 6.03 4.86 3.55 K7V 667 1
20 BD+22 4409 BY* 21 31 01.7141405072 +23 20 07.370852589   10.28 9.253 8.6 7.965 K3Vke 152 0

    Equat.    Gal    SGal    Ecl

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2020.07.08-03:10:17

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