THE CLOSE T TAURI BINARY SYSTEM V4046 Sgr: ROTATIONALLY MODULATED X-RAY EMISSION FROM ACCRETION SHOCKS

被引：29

作者：

Argiroffi, C. ^{[1
,2
]}

Maggio, A. ^{[2
]}

Montmerle, T. ^{[3
]}

Huenemoerder, D. P. ^{[4
]}

Alecian, E. ^{[5
]}

Audard, M. ^{[6
,7
]}

Bouvier, J. ^{[8
]}

Damiani, F. ^{[2
]}

Donati, J. -F. ^{[9
,10
]}

Gregory, S. G. ^{[11
]}

Guedel, M. ^{[12
]}

Hussain, G. A. J. ^{[13
]}

Kastner, J. H. ^{[14
]}

Sacco, G. G. ^{[14
]}

机构：

[1] Univ Palermo, Dipartimento Fis, I-90134 Palermo, Italy

[2] INAF Osservatorio Astron Palermo, I-90134 Palermo, Italy

[3] Inst Astrophys Paris, FR-75014 Paris, France

[4] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA

[5] LESIA, Observ Paris, F-92195 Meudon, France

[6] Univ Geneva, ISDC Data Ctr Astrophys, CH-1290 Versoix, Switzerland

[7] Univ Geneva, Observ Geneve, CH-1290 Versoix, Switzerland

[8] UJF Grenoble 1, CNRS, INSU, IPAG,UMR 5274, F-38041 Grenoble, France

[9] CNRS, IRAP, UMR 5277, F-31400 Toulouse, France

[10] Univ Toulouse, F-31400 Toulouse, France

[11] CALTECH, Dept Astron, Pasadena, CA 91125 USA

[12] Univ Vienna, Dept Astron, A-1180 Vienna, Austria

[13] ESO, D-85748 Garching, Germany

[14] Rochester Inst Technol, Ctr Imaging Sci, Rochester, NY 14623 USA

来源：

ASTROPHYSICAL JOURNAL | 2012年 / 752卷 / 02期

基金：

美国国家科学基金会;

关键词：

accretion; accretion disks; stars: individual (V4046 Sgr); stars: magnetic field; stars: pre-main sequence; stars: variables: T Tauri; Herbig Ae/Be; X-rays: stars; TWIN YOUNG SUNS; MAGNETOSPHERIC ACCRETION; AA TAU; STARS; VARIABILITY; CORONAE; SPECTROSCOPY; DIAGNOSTICS; SPECTRUM; PHOTOEVAPORATION;

D O I：

10.1088/0004-637X/752/2/100

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report initial results from a quasi-simultaneous X-ray/optical observing campaign targeting V4046 Sgr, a close, synchronous-rotating classical T Tauri star (CTTS) binary in which both components are actively accreting. V4046 Sgr is a strong X-ray source, with the X-rays mainly arising from high-density (n(e) similar to 10(11)-10(12) cm(-3)) plasma at temperatures of 3-4 MK. Our multi-wavelength campaign aims to simultaneously constrain the properties of this X-ray-emitting plasma, the large-scale magnetic field, and the accretion geometry. In this paper, we present key results obtained via time-resolved X-ray-grating spectra, gathered in a 360 ks XMM-Newton observation that covered 2.2 system rotations. We find that the emission lines produced by this high-density plasma display periodic flux variations with a measured period, 1.22 +/- 0.01 d, that is precisely half that of the binary star system (2.42 d). The observed rotational modulation can be explained assuming that the high-density plasma occupies small portions of the stellar surfaces, corotating with the stars, and that the high-density plasma is not azimuthally symmetrically distributed with respect to the rotational axis of each star. These results strongly support models in which high-density, X-ray-emitting CTTS plasma is material heated in accretion shocks, located at the base of accretion flows tied to the system by magnetic field lines.

引用

页数：8

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[1] RADIATIVE-TRANSFER OF X-RAYS IN SOLAR CORONA [J].