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The Chandra X-ray observatory monitored the single cool star, AB Doradus, continuously for a period lasting 88ksec (1.98 Prot) in 2002 December with the LETG/HRC-S. The X-ray lightcurve shows significant rotational modulation. It can be…

The Chandra X-ray observatory monitored the single cool star, AB Doradus, continuously for a period lasting 88 ksec (1.98 Prot) in 2002 December with the LETG/HRC-S. The X-ray lightcurve shows rotational modulation, with three peaks that…

We obtain contemporaneous observations of the surface and corona of AB Dor using ground-based circularly polarised spectra from the Anglo-Australian Telescope and X-ray data from the Chandra satellite. The ground-based data are used to…

We probe the relationship between surface magnetic fields and the X-ray emitting corona in the rapidly rotating star AB Dor. Circularly polarised spectra have been inverted to produce a surface (photospheric) magnetic field map. This…

Using long-term X-ray observations, we present the short-term and long-term X-ray variability analysis of the ultra-fast rotating active star AB Dor. Flaring events are common in X-ray observations of AB Dor and occupy a substantial portion…

Solar and Stellar Astrophysics · Physics 2024-03-01 Gurpreet Singh , Jeewan C. Pandey

We re-analyse spectropolarimetric data of AB Dor taken in 1996 December using a surface imaging code that can model the magnetic field of the star as a non-potential current-carrying magnetic field. We find that a non-potential field needs…

Astrophysics · Physics 2009-11-07 G. A. J. Hussain , A. A. van Ballegooijen , M. Jardine , A. Col lier Cameron

We present a multiwavelength study of AB Doradus, combining modelling that incorporates a spectropolarimetric magnetic field map with 8.4 GHz radio interferometry to measure the coronal extent and density of this young star. We use the…

Solar and Stellar Astrophysics · Physics 2024-04-10 C. E. Brasseur , M. M. Jardine , G. A. J. Hussain

In a study of Chandra High Energy Transmission Grating spectra of Algol, we clearly detect Doppler shifts caused by the orbital motion of Algol B. These data provide the first definitive proof that the X-ray emission of Algol is dominated…

Astrophysics · Physics 2009-11-10 Sun Mi Chung , Jeremy J. Drake , Vinay L. Kashyap , Li Wei Lin , Peter W. Ratzlaff

We have modelled the X-ray emission from the young rapid rotator AB Doradus (P = 0.514 days) using as a basis Zeeman-Doppler maps of the surface magnetic field. This allows us to reconcile the apparently conflicting observations of a high…

Astrophysics · Physics 2009-11-07 M. Jardine , K. Wood , A. Collier Cameron , J. -F. Donati , D. H. Mackay

Polar spots are often observed on rapidly-rotating cool stars, but the nature of the magnetic field in these spots is as yet unknown. While Zeeman-Doppler imaging can provide surface magnetic field maps over much of the observed stellar…

Astrophysics · Physics 2009-11-10 T. McIvor , M. Jardine , A. Collier Cameron , K. Wood , J. -F. Donati

The young active star AB Dor (K1 IV-V) has been observed 16 times in the last three years with the XMM-Newton and Chandra observatories, totalling 650 ks of high-resolution X-ray spectra. The XMM/RGS observations with the highest and lowest…

Astrophysics · Physics 2009-11-10 J. Sanz-Forcada , A. Maggio , G. Micela

The active late-type star AB Doradus was observed in February 1996 with the Goddard High Resolution Spectrograph of the Hubble Space Telescope using the low resolution G140L grating. The observations covered one half of the star's rotation…

Astrophysics · Physics 2009-11-06 O. Vilhu , P. Muhli , R. Mewe , P. Hakala

From Zeeman Doppler images of the young, rapidly-rotating K0 dwarf AB Doradus, we have created a potential approximation to the observed radial magnetic field and have evolved it over 30 days due to the observed surface differential…

Astrophysics · Physics 2009-11-07 G. R. Pointer , M. Jardine , A. Collier Cameron , J. -F. Donati

X-ray spectra of the late-type star AB Dor, obtained with the XMM-Newton satellite are analysed. AB Dor was particularly active during the observations. An emission measure reconstruction technique is employed to analyse flare and quiescent…

Astrophysics · Physics 2009-11-10 M. Matranga , M. Mathioudakis , H. R. M. Kay , F. P. Keenan

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…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Lalitha , J. H. M. M. Schmitt

We study the chromosphere and corona of the ultra-fast rotator AB Dor A at high temporal and spectral resolution using simultaneous observations with XMM-Newton in the X-rays, VLT/UVES in the optical, and the ATCA in the radio. Our optical…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Lalitha , B. Fuhrmeister , U. Wolter , J. H. M. M. Schmitt , D. Engels , M. H. Wieringa

We have used Zeeman-Doppler maps of the surface field of the young, rapid rotator AB Dor (P = 0.514 days) to extrapolate the coronal field, assuming it to be potential. We find that the topology of the large-scale field is very similar in…

Astrophysics · Physics 2009-11-07 M. Jardine , A. Collier Cameron , J. F. Donati

We have observed the bright, magnetically active multiple star AB Doradus in a multiwavelength campaign centring around two large facility allocations in November 2006 and January, 2007. Our observations have covered at least three large…

Solar and Stellar Astrophysics · Physics 2015-06-19 O. B. Slee , N. Erkan , M. Johnston-Hollitt , E. Budding

The long-term, high precision photometry delivered by the Transiting Exoplanet Survey Satellite (TESS) enables us to gain new insight into known and hitherto well-studied stars. In this paper, we present the result of our TESS study of the…

Solar and Stellar Astrophysics · Physics 2021-01-04 P. Ioannidis , J. H. M. M. Schmitt

Surface brightness maps for the young K0 dwarf AB Doradus are reconstructed from archival data sets for epochs spanning 1988 to 1994. By using the signal-to-noise enhancement technique of Least-Squares Deconvolution, our results show a…

Astrophysics · Physics 2009-09-29 S. V. Jeffers , J. -F. Donati , A. Collier Cameron
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