The 23rd Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (Tokyo, June 15-19, 2026)
Published June 7, 2026 | Version v1
Poster Open

Measuring and Modeling the Circumplanetary Dust Disk around the Planetary-Mass Companion SR 12 c

Authors/Creators

  • 1. EDMO icon University of Massachusetts, Amherst
  • 2. Univ. Grenoble Alpes/IPAG
  • 3. smith college
  • 4. ROR icon Schmidt Sciences
  • 5. ROR icon Université Paris-Saclay
  • 6. CNRS en Alpes
  • 7. ROR icon Université Grenoble Alpes
  • 8. ROR icon Space Telescope Science Institute
  • 9. ROR icon Johns Hopkins University
  • 10. ROR icon The University of Texas at Austin
  • 11. ROR icon University of California, Santa Barbara
  • 12. ROR icon Amherst College
  • 13. EDMO icon Colgate University
  • 14. Universität Duisburg-Essen
  • 15. EDMO icon John Hopkins University
  • 16. University of Virginia
  • 17. Stockholms universitet
  • 18. ROR icon NSF's NOIRLab
  • 19. ROR icon Université Côte d'Azur
  • 20. ROR icon European Space Astronomy Centre
  • 21. ROR icon Centro de Astrobiología
  • 22. Swedish Defence Research Agency
  • 23. ROR icon Trinity College Dublin
  • 24. ROR icon Stockholm University
  • 25. ROR icon University of Hawaiʻi at Mānoa

Description

SR 12 c, a planetary mass companion in a ~1000 au orbit around its binary host, is one of only three planetary mass objects surrounded by an ALMA-detected circumplanetary disk (CPD). CPDs with different masses and orbits provide crucial laboratories to study substellar formation: the structure and mass of CPDs govern planet formation timescales and may distinguish between formation mechanisms, while dust composition and grain sizes ultimately affect atmospheric metallicity and satellites. CPD properties can also be compared against better-understood brown dwarf and low-mass star disks to test how disk properties scale with central object mass at the low-mass extreme. Spitzer-era studies of disks around brown dwarfs and stars revealed crystalline and amorphous silicates and grain growth to mm sizes. Extending disk characterization to objects of planetary mass requires measurements in the mid-infrared and mm ranges only possible in the era of overlapping ALMA and JWST observations. We present mid-infrared integral field unit observations of SR 12 c and its CPD using JWST/MIRI-MRS. Our observations reveal the SR 12 system embedded within the ρ Oph cloud complex, which adds bright, structured emission with strong H2 rotational lines. We first spatially model and subtract this nebular background before extracting a 5-28 µm spectrum of SR 12 c. We combine this MIRI spectrum with literature photometry and spectroscopy to form a spectral energy distribution (SED) spanning from UV to mm wavelengths. Finally, we present SED modeling using radiative transfer and retrieval codes (MCFOST, DuCKLinG) which explore various disk geometries and multi-temperature components. Preliminary models suggest that SR 12 c’s dust disk has a midplane temperature of ~60 K and surface temperature of ~50-80 K. We discuss implications for this planetary mass companion’s disk size, structure, and composition in the context of the well-characterized landscape of disks around brown dwarfs and stars.

Files

nkerman_coolstars2026_poster_A0_size_MKVIII.pdf

Files (2.1 MB)

Additional details

Software

Repository URL
https://github.com/brynickson/AstroBkgInterp
Programming language
Python