论文标题
HST/WFC3 H $α$直接成像检测AB AUR磁盘腔中的点状源
HST/WFC3 H$α$ Direct-Imaging Detection of a Point-like Source in the Disk Cavity of AB Aur
论文作者
论文摘要
积聚原型可以直接表征行星形成。作为使用哈勃太空望远镜（HST）宽场摄像头3的高对比度成像的一部分，我们呈现AB Aurigae（Ab Aur）的H $α$α$α$α$α$α$α$α$α$α$ ae/be a herbig ae/be be a sar携带过渡磁盘。使用F656N窄带滤波器将数据收集到两个直接成像观测的时期。减去主要恒星的点扩散函数后，我们确定位于p.a的点状源。 $ 182.5^{\ circ} \ pm1.4^{\ circ} $和相对于主机星的分离$ 600 \ pm22 $ 〜mas。该位置与最近确定的Protoplanet候选AB AUR b一致。源在两个单独的时期可见，分别为$ {\ sim} 50 $天，而两个时期的H $α$强度同意。 H $α$通量密度为$f_ν= 1.5 \ pm0.4 $ 〜mjy，$ 3.2 \ pm0.9 $ times的光学连续体，由已发布的HST/stis光度法确定。与PDS 70 B和C相比，H $α$过量排放较弱。中央恒星正在积聚，恒星H $α$发射具有与AB AUR b相似的线与核比率。我们得出的结论是，行星积聚和散落的恒星光都是H $α$发射的可能来源，仅H $α$检测并不能验证AB AUR B作为吸积原行星。解开排放的起源对于在AB AUR磁盘中探测行星形成至关重要。
Accreting protoplanets enable the direct characterization of planet formation. As part of a high-contrast imaging search for accreting planets with the Hubble Space Telescope (HST) Wide Field Camera 3, we present H$α$ images of AB Aurigae (AB Aur), a Herbig Ae/Be star harboring a transition disk. The data were collected in two epochs of direct-imaging observations using the F656N narrow-band filter. After subtracting the point spread function of the primary star, we identify a point-like source located at a P.A. of $182.5^{\circ}\pm1.4^{\circ}$ and a separation of $600\pm22$~mas relative to the host star. The position is consistent with the recently identified protoplanet candidate AB Aur b. The source is visible in two individual epochs separated by ${\sim}50$ days and the H$α$ intensities in the two epochs agree. The H$α$ flux density is $F_ν=1.5\pm0.4$~mJy, $3.2\pm0.9$ times of the optical continuum determined by published HST/STIS photometry. In comparison to PDS 70 b and c, the H$α$ excess emission is weak. The central star is accreting and the stellar H$α$ emission has a similar line-to-continuum ratio as seen in AB Aur b. We conclude that both planetary accretion and scattered stellar light are possible sources of the H$α$ emission, and the H$α$ detection alone does not validate AB Aur b as an accreting protoplanet. Disentangling the origin of the emission will be crucial for probing planet formation in the AB Aur disk.
