Discovery of a point-like source and a third spiral arm in the transition disk around the Herbig Ae star MWC 758
Discovery of a point-like source and a third spiral arm in the transition disk around the Herbig Ae star MWC 758
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在 Herbig Ae 恒星 MWC 758 周围的过渡盘中发现了一个点状源和第三个旋臂
DOI：
10.1051/0004-6361/201732016
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
O. Wertz
中科院分区：
文献类型：
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作者：
M. Reggiani;V. Christiaens;V. Christiaens;O. Absil;D. Mawet;D. Mawet;E. Huby;É. Choquet;C. Gonzalez;G. Ruane;B. Femenía;E. Serabyn;K. Matthews;M. Barraza;B. Carlomagno;D. Defrére;C. Delacroix;C. Delacroix;S. Habraken;A. Jolivet;M. Karlsson;G. O. D. Xivry;P. Piron;J. Surdej;E. V. Catalán;O. Wertz
过渡盘提供了寻找新生行星和研究行星形成早期阶段的非凡机会。在这种情况下，我们观察了赫比格A5星星MWC 758与L波段矢量涡日冕仪安装在近红外相机和光谱仪NIRC 2在凯克II望远镜，目的是揭示螺旋结构的性质，通过限制存在的行星同伴在系统中。我们的高对比度成像观测显示，在MWC 758的南部，在约20 Au（r=0.111+/-0. 111 +/- 0. 11 +/- 004 arcsec）。我们还恢复了两个旋臂（东南和西北），以前的研究已经在偏振光下成像，并发现了星星西南的第三个。在距离该星星0.6弧秒以外的5倍木星质量的系统中没有发现其他伴星。我们认为明亮的L波段发射可能是由嵌入和吸积的原行星的存在引起的，尽管不能排除它是不对称盘特征的可能性。螺旋结构可能与原行星候选者无关，除非在倾斜和偏心的轨道上，它可能是由于一个（或多个）尚未被发现的行星同伴在螺旋图案的边缘或外部。未来的观测和额外的模拟将需要阐明点状源的真实性质及其与螺旋臂的联系。
Transition disks offer the extraordinary opportunity to look for newly born planets and investigate the early stages of planet formation. In this context we observed the Herbig A5 star MWC 758 with the L band vector vortex coronagraph installed in the near-infrared camera and spectrograph NIRC2 at the Keck II telescope, with the aim of unveiling the nature of the spiral structure by constraining the presence of planetary companions in the system. Our high-contrast imaging observations show a bright (delta L=7.0+/-0.3 mag) point-like emission, south of MWC 758 at a deprojected separation of about 20 au (r=0.111+/- 0. 004 arcsec) from the central star. We also recover the two spiral arms (south-east and north-west), already imaged by previous studies in polarized light, and discover a third one to the south-west of the star. No additional companions were detected in the system down to 5 Jupiter masses beyond 0.6 arcsec from the star. We propose that the bright L band emission could be caused by the presence of an embedded and accreting protoplanet, although the possibility of it being an asymmetric disk feature cannot be excluded. The spiral structure is probably not related to the protoplanet candidate, unless on an inclined and eccentric orbit, and it could be due to one (or more) yet undetected planetary companions at the edge of or outside the spiral pattern. Future observations and additional simulations will be needed to shed light on the true nature of the point-like source and its link with the spiral arms.