Academic Journal
Astrometric Accelerations as Dynamical Beacons: A Giant Planet Imaged inside the Debris Disk of the Young Star AF Lep
| Title: | Astrometric Accelerations as Dynamical Beacons: A Giant Planet Imaged inside the Debris Disk of the Young Star AF Lep |
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| Authors: | Kyle Franson, Brendan P. Bowler, Yifan Zhou, Tim D. Pearce, Daniella C. Bardalez Gagliuffi, Lauren I. Biddle, Timothy D. Brandt, Justin R. Crepp, Trent J. Dupuy, Jacqueline Faherty, Rebecca Jensen-Clem, Marvin Morgan, Aniket Sanghi, Christopher A. Theissen, Quang H. Tran, Trevor N. Wolf |
| Source: | The Astrophysical Journal Letters, Vol 950, Iss 2, p L19 (2023) |
| Publisher Information: | IOP Publishing, 2023. |
| Publication Year: | 2023 |
| Collection: | LCC:Astrophysics |
| Subject Terms: | Extrasolar gaseous giant planets, Astrometric exoplanet detection, Direct imaging, Orbit determination, Debris disks, Astrophysics, QB460-466 |
| More Details: | We present the direct-imaging discovery of a giant planet orbiting the young star AF Lep, a 1.2 M _⊙ member of the 24 ± 3 Myr β Pic moving group. AF Lep was observed as part of our ongoing high-contrast imaging program targeting stars with astrometric accelerations between Hipparcos and Gaia that indicate the presence of substellar companions. Keck/NIRC2 observations in $L^{\prime} $ with the vector vortex coronagraph reveal a point source, AF Lep b, at ≈340 mas, which exhibits orbital motion at the 6 σ level over the course of 13 months. A joint orbit fit yields precise constraints on the planet’s dynamical mass of ${3.2}_{-0.6}^{+0.7}$ M _Jup , semimajor axis of ${8.4}_{-1.3}^{+1.1}$ au, and eccentricity of ${0.24}_{-0.15}^{+0.27}$ . AF Lep hosts a debris disk located at ∼50 au, but it is unlikely to be sculpted by AF Lep b, implying there may be additional planets in the system at wider separations. The stellar inclination ( i _* = ${54}_{-9}^{{+11}^\circ} $ ) and orbital inclination ( i _o = ${50}_{-12}^{{+9}^\circ} $ ) are in good agreement, which is consistent with the system having spin–orbit alignment. AF Lep b is the lowest-mass imaged planet with a dynamical mass measurement and highlights the promise of using astrometric accelerations as a tool to find and characterize long-period planets. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 2041-8213 2041-8205 |
| Relation: | https://doaj.org/toc/2041-8205 |
| DOI: | 10.3847/2041-8213/acd6f6 |
| Access URL: | https://doaj.org/article/785ebae8880842c393480cefe6c0fa6d |
| Accession Number: | edsdoj.785ebae8880842c393480cefe6c0fa6d |
| Database: | Directory of Open Access Journals |
| ISSN: | 20418213 20418205 |
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| DOI: | 10.3847/2041-8213/acd6f6 |
| Published in: | The Astrophysical Journal Letters |
| Language: | English |