Confirmation and characterization of the protoplanet HD100546 b - Direct evidence for gas giant planet formation at 50 au
Quanz et al
We present the first multi-wavelength, high-contrast imaging study confirming the protoplanet embedded in the disk around the Herbig Ae/Be star HD100546. The object is detected at L' (~3.8 micron) and M' (~4.8 micron), but not at K_s (~2.1 micron), and the emission consists of a point source component surrounded by spatially resolved emission. For the point source component we derive apparent magnitudes of L'=13.92±0.10 mag, M'=13.33±0.16 mag, and K_s greater than 15.43±0.11 mag (3-σ limit), and a separation and position angle of (0.457±0.014)'' and (8.4±1.4)∘, and (0.472±0.014)'' and (9.2±1.4)∘ in L' and M', respectively. We demonstrate that the object is co-moving with the central star and can reject any (sub-)stellar fore-/background object. Fitting a single temperature blackbody to the observed fluxes of the point source component yields an effective temperature of Teff=1028+227−253 K and a radius for the emitting area of R=6.0+2.5−2.6 Jupiter radii. The best-fit luminosity is L=(2.3+0.9−0.3)⋅10−4 solar luminosities. We quantitatively compare our findings with predictions from evolutionary and atmospheric models for young, gas giant planets, discuss the possible existence of a warm, circumplanetary disk, and note that the de-projected physical separation from the host star of (53±2) au poses a challenge standard planet formation theories. Considering the suspected existence of an additional planet orbiting at ~13-14 au, HD100546 is a unique laboratory to study the formation of multiple gas giant planets empirically.