ALMA Detection of Extended Millimeter Halos in the HD 32297 and HD 61005 Debris Disks

Abstract

We present ALMA 1.3 mm (230 GHz) observations of the HD 32297 and HD 61005 debris disks, two of the most iconic debris disks due to their dramatic swept-back wings seen in scattered light images. These observations achieve sensitivities of 14 and 13 $\mu$Jy beam${}^{-1}$ for HD 32297 and HD 61005, respectively, and provide the highest resolution images of these two systems at millimeter wavelengths to date. By adopting a MCMC modeling approach, we determine that both disks are best described by a two-component model consisting of a broad ($\Delta R/R>0.4$) planetesimal belt with a rising surface density gradient, and a steeply falling outer halo aligned with the scattered light disk. The inner and outer edges of the planetesimal belt are located at $78.5\pm 8.1$ AU and $122\pm 3$ AU for HD 32297, and $41.9\pm 0.9$ AU and $67.0\pm 0.5$ AU for HD 61005. The halos extend to $440\pm 32$ AU and $188\pm 8$ AU, respectively. We also detect ${}^{12}$CO J$=2-1$ gas emission from HD 32297 co-located with the dust continuum. These new ALMA images provide observational evidence that larger, millimeter-sized grains may also populate the extended halos of these two disks previously thought to only be composed of small, micron-sized grains. We discuss the implications of these results for potential shaping and sculpting mechanisms of asymmetric debris disks.

17 pages, 5 figures, published in ApJ

References in corpus (16)

• The Gaia mission
• Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 Solar Mass Main Sequence Stars
• Molecular Gas Clumps from the Destruction of Icy Bodies in the $\beta$ Pictoris Debris Disk
• Probing for Exoplanets Hiding in Dusty Debris Disks: Disk Imaging, Characterization, and Exploration with HST/STIS Multi-Roll Coronagraphy
• Lupus disks with faint CO isotopologues: low gas/dust or large carbon depletion?
• Debris from giant impacts between planetary embryos at large orbital radii
• Exocometary gas structure, origin and physical properties around $\beta$ Pictoris through ALMA CO multi-transition observations
• Molecular gas in debris disks around young A-type stars
• A Complete ALMA Map of the Fomalhaut Debris Disk
• ALMA observations of the debris disk around the young Solar Analog HD 107146
• Apocenter glow in eccentric debris disks: implications for Fomalhaut and epsilon Eridani
• Gas and dust around A-type stars at tens of Myr:signatures of cometary breakup
• 12 and 18 micron images of dust surrounding HD 32297
• CARMA Millimeter-Wave Aperture Synthesis Imaging of the HD 32297 Debris Disk
• Is the HD 15115 inner disk really asymmetrical ?
• A Ring of Warm Dust in the HD 32297 Debris Disk

Cited by in corpus (21)

• Solution to the debris disc mass problem: planetesimals are born small?
• Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
• Solar System Physics for Exoplanet Research
• Population synthesis of exocometary gas around A stars
• Multiple Rings of Millimeter Dust Emission in the HD 15115 Debris Disk
• The vertical structure of debris disks and the impact of gas
• Constraining planetesimal stirring: how sharp are debris disc edges?
• Dust Populations in the Iconic Vega Planetary System Resolved by ALMA
• The Gemini Planet Imager view of the HD 32297 debris disk
• Vertical evolution of exocometary gas: I. How vertical diffusion shortens the CO lifetime
• Extrasolar Kuiper Belts
• Stirred but not shaken: a multi-wavelength view of HD 16743's debris disc
• Giant Impacts and Debris Disk Morphology
• Rave: A non-parametric method for recovering the surface brightness and height profiles of edge-on debris disks
• Dust Spreading in Debris Discs: Do Small Grains Cling on to Their Birth Environment?
• Emerging trends in metallicity and lithium properties of debris disc stars
• Revealing asymmetrical dust distribution in the inner regions of HD 141569
• Relating grain size distributions in circumstellar discs to the spectral index at millimetre wavelengths
• The big sibling of AU Mic: a cold dust-rich debris disk around CP-72 2713 in the $\beta$ Pic moving group
• Four new PLanetesimals Around TYpical and Pre-main seqUence Stars (PLATYPUS) Debris Discs at 8.8mm
• Multi-wavelength, spatially resolved modelling of HD 48682's debris disc