http://arxiv.org/abs/1408.6554
I calculate the spectral energy distributions (SEDs) of accreting circumplanetary disks using atmospheric radiative transfer models. Circumplanetary disks only accreting at $10^{-10}\rm M_{\odot}\,yr^{-1}$ around a 1 M$_{J}$ planet can be brighter than the planet itself. A moderately accreting circumplanetary disk ($\dot{M}\sim 10^{-8}\rm M_{\odot}\,yr^{-1}$; enough to form a 10 M$_{J}$ planet within 1 Myr) around a 1 M$_{J}$ planet has a maximum temperature of $\sim$2000 K, and at near-infrared wavelengths ($J$, $H$, $K$ bands), this disk is as bright as a late M-type brown dwarf or a 10 M$_{J}$ planet with a “hot start”. To distinguish the accretion disks around low mass planets (e.g., 1 M$_{J}$) from brown dwarfs or hot high mass planets, it is crucial to obtain photometry at mid-infrared bands ($L’$, $M$, $N$ bands) because disk SEDs fall off more slowly at longer wavelengths than those of brown dwarfs or planets. If young planets have strong magnetic fields ($\gtrsim$100 G), fields may truncate slowly accreting circumplanetary disks ($\dot{M}\lesssim$10$^{-9}\rm M_{\odot}\,yr^{-1}$) and lead to magnetospheric accretion, which can provide additional accretion signatures, such as UV/optical excess from the accretion shock and line emission.
Z. Zhu
Fri, 29 Aug 14
10/51
Comments: 9 pages, 3 figures, submitted to ApJ
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