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

Abstract

We present 3 years 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$\alpha$ protoplanets. In 2023 and 2024 our sharp (25-27 mas FWHM); well AO corrected (20-26% Strehl), deep (2-3.6hr) images detect compact (r~30 mas; r~3 au) circumplanetary disks (CPDs) surrounding both protoplanets. Starlight scattering off the dusty outer edges of these 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 PSF residuals with pyKLIP ADI and SDI we obtained high-contrast ASDI H$\alpha$ images of both planets in 2022, 2023 and 2024. We find the H$\alpha$ line flux of planet b fell by (8.1$\pm$1.6)x10${}^{-16}$ ergs/s/cm${}^2$ a factor of 4.6 drop in flux from 2022 to 2023. In March 2024, planet b continued to be faint with just a slight 1.6x rise to an H$\alpha$ line flux of (3.64$\pm$0.87)x10${}^{-16}$ ergs/s/cm${}^2$. For c we measure a significant increase of (2.74$\pm$0.51)x10${}^{-16}$ ergs/s/cm${}^2$ from 2023 to 2024 which is a factor of 2.3x increase. So both protoplanets have recently experienced significant H$\alpha$ 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 deg; 2024) with orbital motion roughly consistent with a ~5.6 au orbit.

50 pages, 20 figures, published in January 2025 Astronomical Journal. NOTE Figure D1 has correct planetary mass accretion scale compared to published AJ version

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Cited by in corpus (10)

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• Evidence for Variable Accretion onto PDS 70 c and Implications for Protoplanet Detections
• Differentiating Formation Models with New Dynamical Masses for the PDS 70 Protoplanets
• Inner disc and circumplanetary material in the PDS 70 system
• Keplerian motion of a compact source orbiting the inner disc of PDS 70: a third protoplanet in resonance with b and c?
• Direct Measurement of Extinction in a Planet-Hosting Gap
• A 2 au resolution view by ALMA of the planet-hosting WISPIT 2 disk
• ExoplaNeT accRetion mOnitoring sPectroscopic surveY (ENTROPY) - II. Time series of Balmer line profiles of Delorme 1(AB)b
• Occurrence rates of accreting companions from a new method for computing emission-line survey sensitivity: application to the H-alpha Giant Accreting Protoplanet Survey
• Semianalytical Accretion-Tracer Emission: Forming Planets Are Intrinsically Faint