Zhou, Yifan and Sanghi, Aniket and Bowler, Brendan P. and Wu, Ya-Lin and Close, Laird M. and Long, Feng and Ward-Duong, Kimberly and Zhu, Zhaohuan and Kraus, Adam L. and Follette, Katherine B. and Bae, Jaehan (2022) HST/WFC3 Hα Direct-imaging Detection of a Pointlike Source in the Disk Cavity of AB Aur. The Astrophysical Journal Letters, 934 (1). L13. ISSN 2041-8205
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Abstract
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 Hα 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 narrowband filter. After subtracting the point-spread function of the primary star, we identify a pointlike source located at a position angle of 182fdg5 ± 1fdg4 and a separation of 600 ± 22 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 ∼50 days, and the Hα intensities in the two epochs agree. The Hα flux density is Fν = 1.5 ± 0.4 mJy, 3.2 ± 0.9 times the optical continuum determined by published HST/STIS photometry. In comparison to PDS 70 b and c, the Hα excess emission is weak. The central star is accreting and the stellar Hα 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 Hα emission, and the Hα 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.
Item Type: | Article |
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Subjects: | Open Library Press > Physics and Astronomy |
Depositing User: | Unnamed user with email support@openlibrarypress.com |
Date Deposited: | 27 Apr 2023 06:11 |
Last Modified: | 06 Sep 2024 07:58 |
URI: | http://info.euro-archives.com/id/eprint/1123 |