Abstract
The detection of emission lines associated with accretion processes is a direct method for studying how and where gas giant planets form, how young planets interact with their natal ...protoplanetary disk, and how volatile delivery to their atmosphere takes place. H
α
(
λ
= 0.656
μ
m) is expected to be the strongest accretion line observable from the ground with adaptive optics systems, and is therefore the target of specific high-contrast imaging campaigns. We present MagAO-X and Hubble Space Telescope (HST) data obtained to search for H
α
emission from the previously detected protoplanet candidate orbiting AS209, identified through Atacama Large Millimeter/submillimeter Array observations. No signal was detected at the location of the candidate, and we provide limits on its accretion. Our data would have detected an H
α
emission with
F
H
α
> 2.5 ± 0.3 × 10
−16
erg s
−1
cm
−2
, a factor 6.5 lower than the HST flux measured for PDS70 b. The flux limit indicates that if the protoplanet is currently accreting it is likely that local extinction from circumstellar and circumplanetary material strongly attenuates its emission at optical wavelengths. In addition, the data reveal the first image of the jet north of the star as expected from previous detections of forbidden lines. Finally, this work demonstrates that current ground-based observations with extreme adaptive optics systems can be more sensitive than space-based observations, paving the way to the hunt for small planets in reflected light with extremely large telescopes.
Large segmented aperture ground and space based telescopes are undergoing development to enable direct imaging of extrasolar planets. The ground-based GMT (Giant Magellan Telescope) is planned for ...first light in the mid-2020’s. Future space-based segmented aperture telescope missions, such as LUVOIR (Large UV Optical Infrared Surveyor), will have picometer-level observatory stability requirements for detecting Earth-like planets within the habitable zone. The challenges of high contrast imaging (HCI) for both ground and space applications can be met with extreme adaptive optics (ExAO), a high-order (>=1000 degrees of freedom) adaptive optics (AO) system which performs wavefront sensing and correction at high speed (>=1KHz). In this dissertation, I will describe two ExAO projects, one each for ground and space telescopes, focused on exoplanet detection using HCI. MagAO-X is an NSF-funded ExAO system for the Magellan Clay 6.5-meter telescope at Las Campanas Observatory in Chile which is helping push the limits of HCI. Additionally, MagAO-X is a pathfinder for ExAO instruments on the GMT. I constructed a comprehensive end-to-end (E2E) simulation using Fresnel propagation to characterize the static performance of MagAO-X. The E2E model utilizes both directly measured surfaces and simulated wavefront error maps based on the power spectral density models of the optical surface measurements. For space-based segmented aperture observatories, I will describe a laser guide star (LGS) companion satellite spacecraft which uses a remote beacon to increase the signal available for wavefront sensing and control (WFSC) of the primary segments to help achieve the stringent picometer-stability requirement for the primary mirror segments. I will present a segment cophasing testbed demonstration of correcting the on-axis target point spread function using WFSC on the off-axis LGS source. I will show how these projects push the limits of HCI to enable detecting earth-like exoplanets and ultimately the presence of life in the universe.
ABSTRACT
We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2λ/D (240 mas) in L′ in MagAO/Clio imaging using the binary ...differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric acceleration in Gaia DR3, Hipparcos–Gaia proper motion anomaly, and overluminosity compared to single main-sequence stars. We confirmed the companion, HIP 67506 C, at 0.1 arcsec with MagAO-X in 2022 April. We characterized HIP 67506 C MagAO-X photometry and astrometry, and estimated spectral-type K7-M2; we also re-evaluated HIP 67506 A in light of the close companion. Additionally, we show that a previously identified 9 arcsec companion, HIP 67506 B, is a much further distant unassociated background star. We also discuss the utility of indirect signposts in identifying small inner working angle candidate companions.
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