Magellan Adaptive Optics Imaging of PDS 70: Measuring the Mass Accretion Rate of a Young Giant Planet within a Gapped Disk

Kevin Wagner, Katherine B. Follete, Laird M. Close, Dániel Apai, Aidan Gibbs, Miriam Keppler, André Müller, Thomas Henning, Markus Kasper, Ya Lin Wu, Joseph Long, Jared Males, Katie Morzinski, Melissa McClure

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)

Abstract

PDS 70b is a recently discovered and directly imaged exoplanet within the wide (40 au) cavity around PDS 70. Ongoing accretion onto the central star suggests that accretion onto PDS 70b may also be ongoing. We present the first high-contrast images at Hα (656 nm) and nearby continuum (643 nm) of PDS 70 utilizing the MagAO system. The combination of these filters allows for the accretion rate of the young planet to be inferred, as hot infalling hydrogen gas will emit strongly at Hα over the optical continuum. We detected a source in Hα at the position of PDS 70b on two sequential nights in 2018 May, for which we establish a false positive probability of <0.1%. We conclude that PDS 70b is a young, actively accreting planet. We utilize the Hα line luminosity to derive a mass accretion rate of M Jup yr-1, where the large uncertainty is primarily due to the unknown amount of optical extinction from the circumstellar and circumplanetary disks. PDS 70b represents the second case of an accreting planet interior to a disk gap, and is among the early examples of a planet observed during its formation.

Original languageEnglish
Article numberL8
JournalAstrophysical Journal Letters
Volume863
Issue number1
DOIs
Publication statusPublished - 2018 Aug 10
Externally publishedYes

Keywords

  • planet-disk interactions
  • planets and satellites: detection
  • planets and satellites: formation
  • stars: pre-main sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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