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标题：Keck/NIRC2 L'-band Imaging of Jovian-mass Accreting Protoplanets around PDS 70
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作者：Jason J.Wang (王劲飞) ; Sivan Ginzburg ; Bin Ren (任彬) 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2020
卷号：159
期号：6
页码：3654-3668
DOI：10.3847/1538-3881/ab8aef
语种：English
出版社：American Institute of Physics
摘要：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 RJup.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 MJup and a mean mass accretion rate between 3 × 10−7 and 8 × 10−7 MJup/yr.For PDS 70 c, we computed a mass between 1 and 3 MJup and mean mass accretion rate between 1 × 10−7 and 5 × 10−7 MJup/yr.The mass accretion rates imply dust accretion timescales short enough to hide strong molecular absorption features in both planets' SEDs.
关键词：Exoplanet formation;Exoplanet atmospheres;Orbit determination;Exoplanet dynamics;Coronagraphic imaging