ACCRETING CIRCUMPLANETARY DISKS: OBSERVATIONAL SIGNATURES

作者：Zhu Zhaohuan^*

来源：Astrophysical Journal, 2015, 799(1): 16.

DOI：10.1088/0004-637X/799/1/16

• accretion, accretion disks
• planetary systems
• planets and satellites: formation
• protoplanetary disks
• radiative transfer
• stars: magnetic field
• stars: pre-main sequence

I calculate the spectral energy distributions of accreting circumplanetary disks using atmospheric radiative transfer models. Circumplanetary disks only accreting at 10(-10) M-circle dot yr(-1) around a 1 M-J planet can be brighter than the planet itself. A moderately accreting circumplanetary disk ((M)over dot similar to 10(-8) M-circle dot yr(-1); enough to form a 10 M-J planet within 1 Myr) around a 1 M-J planet has a maximum temperature of similar to 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 use direct imaging to find the accretion disks around low-mass planets (e.g., 1 M-J) and distinguish them from brown dwarfs or hot high-mass planets, it is crucial to obtain photometry at mid-infrared bands (L', M, N bands) because the emission from circumplanetary disks falls off more slowly toward longer wavelengths than those of brown dwarfs or planets. If young planets have strong magnetic fields (greater than or similar to 100 G), fields may truncate slowly accreting circumplanetary disks ((M)over dot less than or similar to 10(-9) M-circle dot 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.

• 出版日期2015-1-20