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, Dániel Apai, Thomas Henning, Carlo F. Manara, Gijs D. Mulders, László Szcs, Nathanial P. Hendler

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


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
Issue number1
StatePublished - Aug 10 2018


  • 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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