Keck/NIRC2 L'-band Imaging of Jovian-mass Accreting Protoplanets around PDS 70

Jason J. Wang, Sivan Ginzburg, Bin Ren, Nicole Wallack, Peter Gao, Dimitri Mawet, Dimitri Mawet, Charlotte Z. Bond, Sylvain Cetre, Peter Wizinowich, Robert J. De Rosa, Garreth Ruane, Michael C. Liu, Olivier Absil, Carlos Alvarez, Christoph Baranec, Élodie Choquet, Mark Chun, Denis Defrère, Jacques Robert DelormeGaspard Duchêne, Pontus Forsberg, Andrea Ghez, Olivier Guyon, Donald N.B. Hall, Elsa Huby, Aïssa Jolivet, Rebecca Jensen-Clem, Nemanja Jovanovic, Mikael Karlsson, Scott Lilley, Keith Matthews, François Ménard, Tiffany Meshkat, Maxwell Millar-Blanchaer, Henry Ngo, Gilles Orban De Xivry, Christophe Pinte, Sam Ragland, Eugene Serabyn, Ernesto Vargas Catalán, Ji Wang, Ed Wetherell, Jonathan P. Williams, Marie Ygouf, Ben Zuckerman

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Abstract

We present L'-band imaging of the PDS 70 planetary system with Keck/NIRC2 using the new infrared pyramid wave front sensor. We detected both PDS 70 b and c in our images, as well as the front rim of the circumstellar disk. After subtracting off a model of the disk, we measured the astrometry and photometry of both planets. Placing priors based on the dynamics of the system, we estimated PDS 70 b to have a semimajor axis of 20-4 +3 au and PDS 70 c to have a semimajor axis of 34-6 +12 au (95% credible interval). We fit the spectral energy distribution (SED) of both planets. For PDS 70 b, we were able to place better constraints on the red half of its SED than previous studies and inferred the radius of the photosphere to be 2-3 R Jup. The SED of PDS 70 c is less well constrained, with a range of total luminosities spanning an order of magnitude. With our inferred radii and luminosities, we used evolutionary models of accreting protoplanets to derive a mass of PDS 70 b between 2 and 4 M Jup and a mean mass accretion rate between 3 × 10-7 and 8 × 10-7 M Jup/yr. For PDS 70 c, we computed a mass between 1 and 3 M Jup and mean mass accretion rate between 1 × 10-7 and 5 × 10-7 M Jup/yr. The mass accretion rates imply dust accretion timescales short enough to hide strong molecular absorption features in both planets' SEDs.

Original languageEnglish
Article number263
Number of pages15
JournalThe Astronomical Journal
Volume159
Issue number6
DOIs
Publication statusPublished - 18 May 2020

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