Magnetic activity and hot Jupiters of young Suns: The weak-line T Tauri stars V819 Tau and V830 Tau
Magnetic activity and hot Jupiters of young Suns: The weak-line T Tauri stars V819 Tau and V830 Tau
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DOI：
10.1093/mnras/stv1837
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发表时间：
2015-09
影响因子：
4.8
通讯作者：
J. Donati;E. H'ebrard;G. Hussain;C. Moutou;L. Malo;K. Grankin;A. Vidotto;S. Alencar;S. Gregory;M. Jardine;G. Herczeg;J. Morin;R. Fares;F. M'enard;J. Bouvier;X. Delfosse;R. Doyon;M. Takami;P. Figueira;P. Petit;I. Boisse;the MaTYSSE collaboration
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作者：
J. Donati;E. H'ebrard;G. Hussain;C. Moutou;L. Malo;K. Grankin;A. Vidotto;S. Alencar;S. Gregory;M. Jardine;G. Herczeg;J. Morin;R. Fares;F. M'enard;J. Bouvier;X. Delfosse;R. Doyon;M. Takami;P. Figueira;P. Petit;I. Boisse;the MaTYSSE collaboration
我们报告的分光偏振和光度监测的弱线金牛座T星（wTTSs）V819头和V830头内的MaTYSSE（年轻恒星的磁性拓扑结构和生存的近距离巨型系外行星）计划，涉及ESPaDOnS分光偏振仪在加拿大-法国-夏威夷望远镜。在近似或等于300万年前，这两颗恒星最近都消散了它们的盘，是探测星星和行星形成的有趣物体。轮廓失真和塞曼签名检测在非偏振和圆偏振线，其旋转调制，我们建模使用断层成像，产生亮度和磁性地图的两颗星。我们发现V819 Tau和V830 Tau的大尺度磁场主要是极向的，并且可以在大半径处近似为350 - 400 G的偶极子，其与旋转轴倾斜近似或等于30度。它们明显弱于GQ Lup的磁场，GQ Lup是一个吸积的经典金牛座星星（cTTS），具有相似的质量和年龄，可以用来比较wTTS和cTTS的磁性。重建的两颗恒星的亮度图包括冷点和暖斑。表面差异旋转很小，通常类似于或等于太阳的4.4倍，与以前的wTTSS结果一致。使用我们的多普勒图像来模拟活动抖动并将其从径向速度（RV）曲线中过滤出来，我们获得了V819 Tau和V830 Tau的RV残差，其离散度分别为0.033和0.104 km s（-1）。RV残差表明，一颗热木星可能正在围绕V830 Tau运行，尽管需要更多的数据来证实这一初步结果。我们在V819 Tau周围没有发现近距离巨行星的证据。
We report results of a spectropolarimetric and photometric monitoring of the weak-line T Tauri stars (wTTSs) V819 Tau and V830 Tau within the MaTYSSE (Magnetic Topologies of Young Stars and the Survival of close-in giant Exoplanets) programme, involving the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope. At similar or equal to 3 Myr, both stars dissipated their discs recently and are interesting objects for probing star and planet formation. Profile distortions and Zeeman signatures are detected in the unpolarized and circularly polarized lines, whose rotational modulation we modelled using tomographic imaging, yielding brightness and magnetic maps for both stars. We find that the large-scale magnetic fields of V819 Tau and V830 Tau are mostly poloidal and can be approximated at large radii by 350-400 G dipoles tilted at similar or equal to 30 degrees to the rotation axis. They are significantly weaker than the field of GQ Lup, an accreting classical T Tauri star (cTTS) with similar mass and age which can be used to compare the magnetic properties of wTTSs and cTTSs. The reconstructed brightness maps of both stars include cool spots and warm plages. Surface differential rotation is small, typically similar or equal to 4.4 times smaller than on the Sun, in agreement with previous results on wTTSs. Using our Doppler images to model the activity jitter and filter it out from the radial velocity (RV) curves, we obtain RV residuals with dispersions of 0.033 and 0.104 km s(-1) for V819 Tau and V830 Tau, respectively. RV residuals suggest that a hot Jupiter may be orbiting V830 Tau, though additional data are needed to confirm this preliminary result. We find no evidence for close-in giant planet around V819 Tau.