An Optical/Near-infrared Investigation of HD 100546 b with the Gemini Planet Imager and MagAO

• Main Authors: Rameau, Julien, Follette, Katherine B., Pueyo, Laurent, Marois, Christian, Macintosh, Bruce, Millar-Blanchaer, Maxwell, Wang, Jason J., Vega, David, Doyon, René, Lafrenière, David, Nielsen, Eric L., Bailey, Vanessa, Chilcote, Jeffrey K., Close, Laird M., Esposito, Thomas M., Males, Jared R., Metchev, Stanimir, Morzinski, Katie M., Ruffio, Jean-Baptiste, Wolff, Schuyler G., Ammons, S. M., Barman, Travis S., Bulger, Joanna, Cotten, Tara, Rosa, Robert J. De, Duchene, Gaspard, Fitzgerald, Michael P., Goodsell, Stephen, Graham, James R., Greenbaum, Alexandra Z., Hibon, Pascale, Hung, Li-Wei, Ingraham, Patrick, Kalas, Paul, Konopacky, Quinn, Larkin, James E., Maire, Jérôme, Marchis, Franck, Oppenheimer, Rebecca, Palmer, David, Patience, Jennifer, Perrin, Marshall D., Poyneer, Lisa, Rajan, Abhijith, Rantakyrö, Fredrik T., Marley, Mark S., Savransky, Dmitry, Schneider, Adam C., Sivaramakrishnan, Anand, Song, Inseok, Soummer, Remi, Thomas, Sandrine, Wallace, J. Kent, Ward-Duong, Kimberly, Wiktorowicz, Sloane
• Other Authors: Univ Arizona, Steward Observ
• Language: en
• Published: IOP PUBLISHING LTD 2017
• Subjects: instrumentation: adaptive optics; planet-disk interactions; planetary systems; stars: individual (HD 100546)
• Online Access: http://hdl.handle.net/10150/624214; http://arizona.openrepository.com/arizona/handle/10150/624214

We present H band spectroscopic and H alpha photometric observations of HD 100546 obtained with the Gemini Planet Imager and the Magellan Visible AO camera. We detect H band emission at the location of the protoplanet HD 100546 b, but show that the choice of data processing parameters strongly affects the morphology of this source. It appears point-like in some aggressive reductions, but rejoins an extended disk structure in the majority of the others. Furthermore, we demonstrate that this emission appears stationary on a timescale of 4.6 years, inconsistent at the 2 sigma level with a Keplerian clockwise orbit at 59 au in the disk plane. The H band spectrum of the emission is inconsistent with any type of low effective temperature object or accreting protoplanetary disk. It strongly suggests a scattered-light origin, as this is consistent with the spectrum of the star and the spectra extracted at other locations in the disk. A nondetection at the 5 sigma level of HD 100546 b in differential H alpha imaging places an upper limit, assuming the protoplanet lies in a gap free of extinction, on the accretion luminosity of 1.7 x 10(-4) L-circle dot and M(M) over dot < 6.3 x 10(-7) M-Jup(2) yr(-1) for 1 R-Jup. These limits are comparable to the accretion luminosity and accretion rate of T-Tauri stars or LkCa 15 b. Taken together, these lines of evidence suggest that the H band source at the location of HD 100546 b is not emitted by a planetary photosphere or an accreting circumplanetary disk but is a disk feature enhanced by the point-spread function subtraction process. This non-detection is consistent with the non-detection in the K. band reported in an earlier study but does not exclude the possibility that HD 100546 b is deeply embedded.