We present and analyze a new M' detection of the young exoplanet beta Pictoris b from 2008 VLT/NaCo data at a separation of ~ 4 AU and a high signal-to-noise rereduction of L' data taken in December 2009. Based on our orbital analysis, the planet's orbit is viewed almost perfectly edge-on (i ~ 89 degrees) and has a Saturn-like semimajor axis of 9.50 (+3.93, -1.7) AU. Intriguingly, the planet's orbit is aligned with the major axis of the outer disk (Omega ~ 31 degrees) but probably misaligned with the warp/inclined disk at 80 AU often cited as a signpost for the planet's existence. Our results motivate new studies to clarify how $β$ Pic b sculpts debris disk structures and whether a second planet is required to explain the warp/inclined disk.
Evolution of Spin Direction of Accreting Magnetic Protostars and Spin-Orbit Misalignment in Exoplanetary Systems: II. Warped Discs
原恒星与其吸积盘之间的磁相互作用往往会导致吸积盘的翘曲,并使恒星的自旋方向发生长期变化,因此自旋轴可能并不总是垂直于吸积盘。这可能有助于解释最近在一些系外行星系统中观察到的自旋轨道不对准。我们研究了磁翘曲/进动扭矩和内部应力的联合作用下的翘曲原行星盘的动力学,包括翘曲的粘性阻尼和弯曲波的传播。我们表明,当外盘轴与恒星的自旋轴不一致,光盘的演变对一个扭曲的稳定状态的时间尺度上,取决于光盘的粘度或弯曲波的传播速度,但在所有情况下,是远远短于自旋演化的时间尺度(百万年的顺序)。此外,对于最有可能的物理参数表征磁性原恒星,拱星盘和它们的相互作用,稳态盘有一个相当小的翘曲,这样,整个磁盘近似位于一个单一的平面所确定的外盘边界条件,虽然更极端的参数可能会引起更大的磁盘翘曲。与我们最近基于平盘的分析(Lai et al. 2010)一致,我们发现恒星上轻微翘曲盘的反作用磁矩可以使恒星自旋轴与盘轴对齐,也可以将其推向不对齐,这取决于星盘系统的参数。这意味着新形成的行星系可能在恒星自转轴和行星轨道对称轴之间有一定的倾角范围。
The multi-wavelength vertical structure of the archetypal $β$ Pictoris debris disk
California Institute of Technology(加州理工学院);University of Cambridge(剑桥大学);University of Belgrade(贝尔格莱德大学);University of Oxford(牛津大学);ALMA JAO(阿塔卡马大型毫米波/亚毫米波阵列联合运营办公室);Wesleyan University(卫斯理安大学);Trinity College Dublin, the University of Dublin(都柏林三一学院,都柏林大学)
VLTI/MATISSE observations of the hot dust around $β$ Pictoris: Observing faint objects with MATISSE
Univ. Grenoble Alpes, CNRS, IPAG(格勒诺布尔阿尔卑斯大学);Univ. Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange(蔚蓝海岸大学,蔚蓝海岸天文台);Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN(孔科利天文台,地球与天文学研究中心);CSFK, MTA Centre of Excellence(匈牙利科学院天文学研究所,MTA卓越中心);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心)
Deep HST/STIS Coronagraphic Imaging of the $β$ Pictoris Debris Disk: On the Scattered Light Component of the Cat's Tail
The University of Arizona(亚利桑那大学);Centro de Astrobiología (CAB, CSIC-INTA)(天体生物学中心(CAB,CSIC-INTA));Space Telescope Science Institute(太空望远镜科学研究所);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心)