UV-optical Emission of AB Aur b Is Consistent with Scattered Stellar Light

Authors

Yifan Zhou, The University of Texas at Austin
Brendan P. Bowler, The University of Texas at Austin
Haifeng Yang, Peking University
Aniket Sanghi, The University of Texas at Austin
Gregory J. Herczeg, Peking University
Adam L. Kraus, The University of Texas at Austin
Jaehan Bae, College of Liberal Arts and Sciences
Feng Long, The University of Arizona
Katherine B. Follette, Amherst College
Kimberly Ward-Duong, Smith CollegeFollow
Zhaohuan Zhu, University of Nevada, Las Vegas
Lauren Biddle, The University of Texas at Austin
Laird M. Close, The University of Arizona
Lillian Yushu Jiang, The University of Texas at Austin
Ya Lin Wu, National Taiwan Normal University

Author ORCID Identifier

Kimberly Ward-Duong: 0000-0002-4479-8291

Document Type

Article

Publication Date

12-1-2023

Publication Title

Astronomical Journal

Abstract

The proposed protoplanet AB Aur b is a spatially concentrated emission source imaged in the millimeter-wavelength disk gap of the Herbig Ae/Be star AB Aur. Its near-infrared spectrum and absence of strong polarized light have been interpreted as evidence supporting the protoplanet interpretation. However, the complex scattered-light structures in the AB Aur disk pose challenges in resolving the emission source and interpreting the true nature of AB Aur b. We present new images of the AB Aur system obtained using the Hubble Space Telescope Wide Field Camera 3 in the ultraviolet (UV) and optical bands. AB Aur b and the known disk spirals are recovered in the F336W, F410M, and F645N bands. The spectral energy distribution of AB Aur b shows absorption in the Balmer jump, mimicking that of early-type stars. By comparing the colors of AB Aur b to those of the host star, the disk spirals, and predictions from scattered light and self-luminous models, we find that the emission from AB Aur b is inconsistent with planetary photospheric or accretion shock models. Instead, it is consistent with those measured in the circumstellar disks that trace scattered light. We conclude that the UV and visible emission from AB Aur b does not necessitate the presence of a protoplanet. We synthesize observational constraints on AB Aur b and discuss inconsistent interpretations among different data sets. Considering the significance of the AB Aur b discovery, we advocate for further observational evidence to verify its planetary nature.

Volume

166

Issue

6

DOI

10.3847/1538-3881/acf9ec

ISSN

00046256

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Rights

© 2023 The Authors

Comments

Archived as published.

Recommended Citation

Zhou, Yifan; Bowler, Brendan P.; Yang, Haifeng; Sanghi, Aniket; Herczeg, Gregory J.; Kraus, Adam L.; Bae, Jaehan; Long, Feng; Follette, Katherine B.; Ward-Duong, Kimberly; Zhu, Zhaohuan; Biddle, Lauren; Close, Laird M.; Jiang, Lillian Yushu; and Wu, Ya Lin, "UV-optical Emission of AB Aur b Is Consistent with Scattered Stellar Light" (2023). Astronomy: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/ast_facpubs/145