DISCOVERY OF A COMPANION CANDIDATE IN THE HD 169142 TRANSITION DISK AND THE POSSIBILITY OF MULTIPLE PLANET FORMATION
DISCOVERY OF A COMPANION CANDIDATE IN THE HD 169142 TRANSITION DISK AND THE POSSIBILITY OF MULTIPLE PLANET FORMATION
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HD 169142 过渡盘中发现的伴星候选者以及多行星形成的可能性
DOI：
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发表时间：
2014
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通讯作者：
J. Torrelles
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作者：
M. Reggiani;S. Quanz;M. Meyer;L. Pueyo;O. Absil;A. Amara;G. Anglada;H. Avenhaus;Julien H. Girard;C. Gonzalez;J. Graham;D. Mawet;F. Meru;J. Milli;M. Osorio;S. Wolff;J. Torrelles
我们分别用甚大望远镜/纳科AGPM矢量涡旋日冕仪和双子行星成像仪对HD 169142进行了L′和J波段高对比度观测。一个位于主星星北0.“156 ± 0.”032（P. A. = 7.°4 ± 11.°3）出现在最终的缩小L′图像中。在距离该星星145秒差距处，这个角距对应的物理距离为22.7 ± 4.7 Au，将源定位在最近解析的过渡盘内腔中。这个源的亮度为L′ = 12.2 ± 0.5等，但在J波段（J >13.8等）没有被探测到。根据COND模型，如果它的L′亮度仅仅来自伴星的光球层，并且给出了J-L ′色的限制，那么它将对应于一个在星星年龄为28-32 M的木星天体。然而，这颗星星正在进行的吸积活动表明，气体留在了内盘腔中，伴星也可能从内盘腔中吸积。在这种情况下，该物体的质量可能较低，其光度可能因吸积过程和环行星盘而增强。质量较低的物体与观察到的空腔宽度更一致。最后，观测结果使我们能够对第二个伴星的L′波段通量设定一个上限，该伴星的轨道在盘环隙中，轨道高度为150 Au，这与毫米波观测结果一致。如果第二个伴星也被确认，HD 169142可能正在形成一个行星系统，至少有两个伴星打开间隙，并可能相互作用。
We present L′- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located at 0.″156 ± 0.″032 north of the host star (P.A. = 7.°4 ± 11.°3) appears in the final reduced L′ image. At the distance of the star (∼145 pc), this angular separation corresponds to a physical separation of 22.7 ± 4.7 AU, locating the source within the recently resolved inner cavity of the transition disk. The source has a brightness of L′ = 12.2 ± 0.5 mag, whereas it is not detected in the J band (J >13.8 mag). If its L′ brightness arose solely from the photosphere of a companion and given the J − L′ color constraints, it would correspond to a 28–32 MJupiter object at the age of the star, according to the COND models. Ongoing accretion activity of the star suggests, however, that gas is left in the inner disk cavity from which the companion could also be accreting. In this case, the object could be lower in mass and its luminosity enhanced by the accretion process and by a circumplanetary disk. A lower-mass object is more consistent with the observed cavity width. Finally, the observations enable us to place an upper limit on the L′-band flux of a second companion candidate orbiting in the disk annular gap at ∼50 AU, as suggested by millimeter observations. If the second companion is also confirmed, HD 169142 might be forming a planetary system, with at least two companions opening gaps and possibly interacting with each other.