HST/WFC3 Hα Direct-imaging Detection of a Pointlike Source in the Disk Cavity of AB Aur

Zhou, Yifan; Sanghi, Aniket; Bowler, Brendan P.; Wu, Ya-Lin; Close, Laird M.; Long, Feng; Ward-Duong, Kimberly; Zhu, Zhaohuan; Kraus, Adam L.; Follette, Katherine B.; Bae, Jaehan

doi:10.3847/2041-8213/ac7fef

Cited by 25 publications

(23 citation statements)

References 58 publications

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“…Contrary to the stellar case, accretion in brown dwarfs or planetary-mass companions (PMCs) has only more recently, thanks to advancements in instrumentation and post-processing techniques, become accessible for study (e.g. Haffert et al 2019;Eriksson et al 2020;Stolker et al 2021;Currie et al 2022;Zhou et al 2022). The most widely studied of these are the two protoplanets in the 5 Myr PDS 70 system (Keppler et al 2018;Müller et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b

Ringqvist

Viswanath

Aoyama

et al. 2023

A&A

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Context. Accretion at planetary-mass companions (PMCs) suggests the presence of a protoplanetary disc in the system, likely accompanied by a circumplanetary disc. High-resolution spectroscopy of accreting PMCs is very difficult due to their proximity to bright host stars. For well-separated companions, however, such spectra are feasible and they are unique windows into accretion. Aims. We have followed up on our observations of the 40-Myr, and still accreting, circumbinary PMC Delorme 1 (AB)b. We used high-resolution spectroscopy to characterise the accretion process further by accessing the wealth of emission lines in the near-UV. Methods. We have used the UVES spectrograph on the ESO VLT/UT2 to obtain R λ ≈ 50000 spectroscopy, at 3300-4520 Å, of Delorme 1 (AB)b. After separating the emission of the companion from that of the M5 low-mass binary, we performed a detailed emission-line analysis, which included planetary accretion shock modelling. Results. We reaffirm ongoing accretion in Delorme 1 (AB)b and report the first detections in a (super-Jovian) protoplanet of resolved hydrogen line emission in the near-UV (Hγ, Hδ, H , H8, and H9). We tentatively detect H11, H12, He i, and Ca ii H/K. The analysis strongly favours a planetary accretion shock with a line-luminosity-based accretion rate of Ṁ = 2 × 10 −8 M J yr −1 . The lines are asymmetric and are well described by sums of narrow and broad components with different velocity shifts. The overall line shapes are best explained by a pre-shock velocity of v 0 = 170 ± 30 km s −1 , implying a planetary mass of M P = 13 ± 5 M J , and number densities of n 0 10 13 cm −3 or n 0 ∼ 10 11 cm −3 . The higher density implies a small line-emitting area of ∼ 1% relative to the planetary surface. This favours magnetospheric accretion, a case potentially strengthened by the presence of blueshifted emission in the line profiles. Conclusions. High-resolution spectroscopy offers the opportunity to resolve line profiles, which are crucial for studying the accretion process in depth. The super-Jovian protoplanet Delorme 1 (AB)b is still accreting at ∼ 40 Myr. Thus, Delorme 1 belongs to the growing family of 'Peter Pan disc' systems with (a) protoplanetary and/or circumplanetary disc(s) far beyond the typically assumed disc lifetimes. Further observations of this benchmark companion and its presumed disc(s) will help answer key questions about the accretion geometry in PMCs.

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Section: Introductionmentioning

confidence: 99%

Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b

Ringqvist

Viswanath

Aoyama

et al. 2023

A&A

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“…Here we tested the performance of SSD on extended sources using a SCExAO/MEC y-band observation of AB Aurigae (AB Aur) taken on 2021 October 14. AB Aur is a well-studied system with a known protoplanetary disk that also harbors a recently discovered protoplanet (Boccaletti et al 2020;Currie et al 2022;Zhou et al 2022). AB Aur was observed using SCExAO/MEC for 16 minutes in exceptional seeing conditions of ∼0 3.…”

Section: Ssd On Ab Aurmentioning

confidence: 99%

Probing Photon Statistics in Adaptive Optics Images with SCExAO/MEC*

Steiger

Brandt

Guyon

et al. 2022

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We present an experimental study of photon statistics for high-contrast imaging with the Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera (MEC) located behind the Subaru Coronagraphic Extreme Adaptive Optics System at the Subaru Telescope. We show that MEC measures the expected distributions for both on-axis companion intensity and off-axis intensity, which manifests as quasi-static speckles in the image plane and currently limits high-contrast imaging performance. These statistics can be probed by any MEC observation due to the photon-counting capabilities of MKID detectors. Photon arrival time statistics can also be used to directly distinguish companions from speckles using a post-processing technique called Stochastic Speckle Discrimination (SSD). Here, we give an overview of the SSD technique and highlight the first demonstration of SSD on an extended source—the protoplanetary disk AB Aurigae. We then present simulations that provide an in-depth exploration as to the current limitations of an extension of the SSD technique called Photon-Counting SSD (PCSSD) to provide a path forward for transitioning PCSSD from simulations to on-sky results. We end with a discussion of how to further improve the efficacy of such arrival-time-based post-processing techniques applicable to both MKIDs, as well as other high-speed astronomical cameras.

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“…DI has the advantage of forming dense, self-gravitating clumps in a few orbital periods, relaxing the disk lifetime constraint for forming wide-orbit gas giants in situ (e.g., Boss 2011). Evidence for a gas giant protoplanet embedded in a spiral arm 93 au from AB Aurigae has been interpreted as an example of gas giant planet formation by DI (Currie et al 2022 see Cadman et al 2021;Zhou et al 2022). DI has also been proposed as the source of the ∼10M Jup exoplanet that orbits ∼560 au from the massive binary b Centauri (Janson et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Orbital Migration of Protoplanets in a Marginally Gravitationally Unstable Disk. II. Migration, Merging, and Ejection

Boss

2023

ApJ

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Protoplanets formed in a marginally gravitationally unstable (MGU) disk by either core accretion or disk instability will be subject to dynamical interactions with massive spiral arms, possibly resulting in inward or outward orbital migration, mergers with each other, or even outright ejection from the protoplanetary system. The latter process has been hypothesized as a possible formation scenario for the unexpectedly high frequency of unbound gas giant exoplanets (free floating planets, FFPs). Previous calculations with the EDTONS fixed grid three-dimensional (3D) hydrodynamics code found that protoplanets with masses from 0.01 M ⊕ to 3 M Jup could undergo chaotic orbital evolutions in MGU disks for ∼1000 yr without undergoing monotonic inward or outward migration. Here the Enzo 2.5 adaptive mesh refinement 3D hydrodynamics code is used to follow the formation and orbital evolution of protoplanets in MGU disks for up to 2000 yr. The Enzo results confirm the basic disk fragmentation results of the EDTONS code, as well as the absence of monotonic inward or outward orbital migration. In addition, Enzo allows protoplanet mergers to occur, unlike EDTONS, resulting in a significant decrease in the number of protoplanets that survive for 1000–2000 yr in the Enzo models. These models also imply that gas giants should be ejected frequently in MGU disks that fragment into large numbers of protoplanets, supporting ejection as a possible source mechanism for the observed FFPs.

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HST/WFC3 Hα Direct-imaging Detection of a Pointlike Source in the Disk Cavity of AB Aur

Cited by 25 publications

References 58 publications

Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b

Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b

Probing Photon Statistics in Adaptive Optics Images with SCExAO/MEC*

Orbital Migration of Protoplanets in a Marginally Gravitationally Unstable Disk. II. Migration, Merging, and Ejection

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