An ALMA 1.3 millimeter Search for Debris Disks around Solar-type Stars in the Pleiades

TL;DR

This study used ALMA 1.3mm observations to search for debris disks around 76 Solar-type stars in the Pleiades, finding no significant detections and providing constraints on debris disk evolution at this age.

Contribution

First ALMA 1.3mm survey of Solar-type stars in the Pleiades, offering new constraints on debris disk evolution at ~115 Myr.

Findings

No significant debris disk detections around the stars.

Results are consistent with steady-state collisional cascade models.

Two stars show excess emission possibly due to dynamical events.

Abstract

Millimeter emission from debris disks around stars of different ages provides constraints on the collisional evolution of planetesimals. We present ALMA 1.3 millimeter observations of a sample of 76 Solar-type stars in the ~115 Myr old Pleiades star cluster. These ALMA observations complement previous infrared observations of this sample by providing sensitivity to emission from circumstellar dust at lower temperatures, corresponding to debris at radii comparable to the Kuiper Belt and beyond. The observations obtain a beam size of 1.5 arcsec (200 au) and a median rms noise of 54 mircoJy/beam, which corresponds to a fractional luminosity $L_{dust}/L_{star} \sim 10^{-4}$ for 40 K dust for a typical star in the sample. The ALMA images show no significant detections of the targeted stars. We interpret these limits in the context of a steady-state collisional cascade model for debris disk evolution that provides a good description of observations of the field population near the Sun but is not well-calibrated on younger populations.The ALMA non-detections of the Pleiades systems are compatible with the disk flux predictions of this model. We find no high fractional luminosity outliers from these ALMA data that could be associated with enhanced collisions resulting from activity not accounted for by steady-state evolution. However, we note that two systems (HII 1132 and HD 22680) show 24 micron excess much higher than the predictions of this model, perhaps due to unusually high dust production from dynamical events involving planets.