CONFIRMATION AND CHARACTERIZATION OF THE PROTOPLANET HD 100546 b—DIRECT EVIDENCE FOR GAS GIANT PLANET FORMATION AT 50 AU

Abstract

We present the first multi-wavelength, high-contrast imaging study confirming the protoplanet embedded in the disk around the Herbig Ae/Be star HD 100546. The object is detected at L? () and M? (), but not at Ks (), and the emission consists of a point source component surrounded by spatially resolved emission. For the point source component we derive apparent magnitudes of mag, mag, and mag (3? limit), and a separation and position angle of and , and and in L? and M?, respectively. We demonstrate that the object is co-moving with HD 100546 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 K and a radius for the emitting area of . The best-fit luminosity is . 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 deprojected physical separation from the host star of AU poses a challenge to standard planet formation theories. Considering the suspected existence of an additional planet orbiting at ?13?14 AU, HD 100546 appears to be an unprecedented laboratory to study the formation of multiple gas giant planets empirically.