Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust
Laird M. Close, Jared R. Males, Jialin Li, Sebastiaan Y. Haffert, Joseph D. Long, Alexander D. Hedglen, Alycia J. Weinberger, Katherine B. Follette, Dániel Apai, René Doyon, Warren G. Foster, Victor Gasho, Kyle Van Gorkom, Olivier Guyon, Maggie Kautz, Jay K. Kueny, Jennifer Lumbres, A. McLeod, Eden McEwen, Clarissa Pavao, Logan Pearce, Laura M. Pérez, Lauren Schatz, J. Szulágyi, Kevin Wagner, Ya-Lin Wu
Abstract
Abstract We present 3 yr of high-contrast imaging of the PDS 70 b and c accreting protoplanets with the new extreme AO system MagAO-X as part of the MaxProtoPlanetS survey of H α protoplanets. In 2023 and 2024, our sharp (25–27 mas FWHM), well-AO-corrected (20%–26% Strehl), deep (2–3.6 hr) images detected compact ( r ∼ 30 mas; r ∼ 3 au) circumplanetary disks (CPDs) surrounding both protoplanets. Starlight scattering off the front edge of these dusty CPDs is the likely source of the bright compact continuum light detected within ∼30 mas of both planets in our simultaneously obtained continuum 668 nm filter images. After subtraction of contaminating continuum and point-spread function residuals with pyKLIP angular differential imaging and spectral differential imaging, we obtained high-contrast ASDI H α images of both planets in 2022, 2023, and 2024. We find the H α line flux of planet b fell by (8.1 ± 1.6) × 10 −16 erg s −1 cm −2 , a factor of 4.6 drop in flux from 2022 to 2023. In 2024 March, planet b continued to be faint with just a slight 1.6× rise to an H α line flux of (3.64 ± 0.87) × 10 −16 erg s −1 cm −2 . For c, we measure a significant increase of (2.74 ± 0.51) × 10 −16 erg s −1 cm −2 from 2023 to 2024, which is a factor of 2.3 increase. So both protoplanets have recently experienced significant H α variability with ∼1 yr sampling. In 2024, planet c is brighter than b: as c is brightening and b generally fading. We also tentatively detect one new point source “CC3” inside the inner disk (∼49 mas; at PA ∼ 295°; 2024) with orbital motion roughly consistent with a ∼5.6 au orbit.