Observability of forming planets and their circumplanetary discs - I. Parameter study for ALMA
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Authors: Szulagyi, J.; van der Plas, G.; Meyer, M. R.; Pohl, A.; Quanz, S. P.; Mayer, L.; Daemgen, S.; Tamburello, V.
Abstract
We present mock observations of forming planets with Atacama Large Millimeter Array (ALMA). The possible detections of circumplanetary discs (CPDs) were investigated around planets of Saturn, 1, 3, 5, and 10 Jupiter-masses that are placed at 5.2 au from their star. The radiative, 3D hydrodynamic simulations were then post-processed with RADMC3D and the ALMA observation simulator. We found that even though the CPDs are too small to be resolved, they are hot due to the accreting planet in the optically thick limit; therefore, the best chance to detect them with continuum observations in this case is at the shortest ALMA wavelengths, such as band 9 (440 mu m). Similar fluxes were found in the case of Saturn and Jupiter-mass planets, as for the 10 M-Jup gas-giant, due to temperature-weighted optical depth effects: when no deep gap is carved, the planet region is blanketed by the optically thick circumstellar disc leading to a less efficient cooling there. A test was made for a 52 au orbital separation, which showed that optically thin CPDs are also detectable in band 7 but they need longer integration times (> 5 h). Comparing the gap profiles of the same simulation at various ALMA bands and the hydro simulation confirmed that they change significantly, first because the gap is wider at longer wavelengths due to decreasing optical depth; secondly, the beam convolution makes the gap shallower and at least 25 per cent narrower. Therefore, caution has to be made when estimating planet masses based on ALMA continuum observations of gaps.
GEMINI PLANET IMAGER OBSERVATIONS OF THE AU MICROSCOPII DEBRIS DISK: ASYMMETRIES WITHIN ONE ARCSECOND
ASTROPHYSICAL JOURNAL LETTERS
Authors: Wang, Jason J.; Graham, James R.; Pueyo, Laurent; Nielsen, Eric L.; Millar-Blanchaer, Max; De Rosa, Robert J.; Kalas, Paul; Ammons, S. Mark; Bulger, Joanna; Cardwell, Andrew; Chen, Christine; Chiang, Eugene; Chilcote, Jeffrey K.; Doyon, Rene; Draper, Zachary H.; Duchene, Gaspard; Esposito, Thomas M.; Fitzgerald, Michael P.; Goodsell, Stephen J.; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Hinkley, Sasha; Hung, Li-Wei; Ingraham, Patrick; Larkin, James E.; Macintosh, Bruce; Maire, Jerome; Marchis, Franck; Marois, Christian; Matthews, Brenda C.; Morzinski, Katie M.; Oppenheimer, Rebecca; Patience, Jenny; Perrin, Marshall D.; Rajan, Abhijith; Rantakyroe, Fredrik T.; Sadakuni, Naru; Serio, Andrew; Sivaramakrishnan, Anand; Soummer, Remi; Thomas, Sandrine; Ward-Duong, Kimberly; Wiktorowicz, Sloane J.; Wolff, Schuyler G.
Abstract
We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1 '' (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side at similar separations. This part of the disk is also vertically offset by 69 +/- 30 mas to the northeast at 1 '' when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction similar to 50 mas between 0 ''.4 and 1 ''.2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for similar to 4 M-Jup planets at 4 AU. We detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.