Observability of Forming Planets and their Circumplanetary Disks IV. -- with JWST & ELT

Abstract: To understand the potential for observing forming planets and their circumplanetary disks (CPDs) with JWST and ELT, we created mock observations from 3D radiative hydrodynamic simulations and radiative transfer post-processing for planets with 10, 5, 1 Jupiter and 1 Saturn masses with orbital separation of 50 and 30 AU in 0$^{\circ}$, 30$^{\circ}$ and 60$^{\circ}$ inclinations. Instrumental effects were then simulated with Mirage for JWST/NIRCam and NIRISS, MIRISim for JWST/MIRI and SimCADO & SimMETIS for ELT/MICADO and METIS. We found that the longer wavelengths (mid-IR and beyond) are the best to detect CPDs. Longer is the wavelength, the smaller mass planet's CPD could be detected. MIRI on JWST and METIS on ELT offers the best possibility on these telescopes. Specifically, below 3 $\mu$m, only 10 $M_{\mathrm{Jup}}$ planets with their CPDs are detectable with NIRCam and MICADO. 5 $M_{\mathrm{Jup}}$ planets are only detectable if at 30 AU (i.e. closer) orbital separation. Planets above 5 $M_{\mathrm{Jup}}$ with their CPDs are detectable between 3-5 $\mu$m with NIRCam and METIS L/M band, or above 10 $\mu$m with MIRI and METIS N band. For $\leq$ 1 $M_{\mathrm{Jup}}$ planets > 15 $\mu$m are needed, where MIRI uniquely offers imaging capability. We present magnitudes and spectral energy distributions for separate components of the planet+CPD+CSD system, to differentiate the extinction rates of CPDs and CSDs and to provide predictions for observational proposals. Because the CPD turns out to be the main absorber of the planet's emission, especially <10 $\mu$m, this makes the detection of forming planets quite challenging.