An ALMA Survey of Faint Disks in the Chamaeleon i Star-forming Region: Why Are Some Class II Disks so Faint?

Feng Long, Gregory J. Herczeg, Ilaria Pascucci, Daniel Apai, Thomas Henning, Carlo F. Manara, Gijs D. Mulders, László Szcs, Nathanial P. Hendler

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4 Scopus citations

Abstract

ALMA surveys of nearby star-forming regions have shown that the dust mass in the disk is correlated with the stellar mass, but with a large scatter. This scatter could indicate either different evolutionary paths of disks or different initial conditions within a single cluster. We present ALMA Cycle 3 follow-up observations for 14 Class II disks that were low signal-to-noise (S/N) detections or non-detections in our Cycle 2 survey of the ∼2 Myr old Chamaeleon I star-forming region. With five times better sensitivity, we detect millimeter dust continuum emission from six more sources and increase the detection rate to 94% (51/54) for Chamaeleon I disks around stars earlier than M3. The stellar-disk mass scaling relation reported in Pascucci et al. is confirmed with these updated measurements. Faint outliers in the F mm-M plane include three non-detections (CHXR71, CHXR30A, and T54) with dust mass upper limits of 0.2 M and three very faint disks (CHXR20, ISO91, and T51) with dust masses ∼0.5 M . By investigating the SED morphology, accretion property and stellar multiplicity, we suggest for the three millimeter non-detections that tidal interaction by a close companion (≲100 au) and internal photoevaporation may play a role in hastening the overall disk evolution. The presence of a disk around only the secondary star in a binary system may explain the observed stellar SEDs and low disk masses for some systems.

Original languageEnglish (US)
Article number61
JournalAstrophysical Journal
Volume863
Issue number1
DOIs
Publication statusPublished - Aug 10 2018

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Keywords

  • binaries: close
  • protoplanetary disks
  • stars: pre-main sequence
  • submillimeter: planetary systems

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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