Debris discs in the 27 Myr old open cluster IC4665

Abstract

We present Spitzer IRAC and MIPS 24um imaging of members of the 27+/-5Myr old open cluster IC 4665. Models for the assembly of terrestrial planets through planetesimal collisions and mergers predict episodic dust debris discs at this epoch. We determine that 42(+18-13)% of the solar-type (F5-K5) cluster members have excess emission at 24um indicative of these debris discs, the highest frequency of the clusters studied with Spitzer to date. The majority of these discs have intermediate levels of excess (F_24/F_phot < 2), and no source is found to have extreme levels of excess indicative of a recent transient event as opposed to steady-state collisional evolution. We find no evidence of a link between multiplicity and 24um excess in this cluster sample. Only the early-type star TYC424-473-1 (T_eff~8420K) has significant near-infrared excess from 4.5um as measured with IRAC. Two solar-type targets have low significance 8um excess but no significant 24um excess. All other targets show no evidence for near-infrared excess which could indicate the presence of an optically thick primordial disc, demonstrating that the observed 24um excess arises from a debris disc.

14 pages, 11 figures, accepted for publication in MNRAS

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Cited by in corpus (11)

• Debris from terrestrial planet formation: the Moon-forming collision
• A Comprehensive Census of Nearby Infrared Excess Stars
• Variations on Debris Disks III. Collisional Cascades and Giant Impacts in the Terrestrial Zones of Solar-type Stars
• The first 40 million years of circumstellar disk evolution: the signature of terrestrial planet formation
• Rocky Planet Formation: Quick and Neat
• An active asteroid belt causing the UX Ori phenomenon in RZ Psc
• Photometry Transformation from RGB Bayer Filter System to Johnson-Cousins BVR Filter System
• Dust discs around intermediate mass and Sun-like stars in the 16 Myr old NGC 1960 open cluster
• Influence of planets on debris disks in star clusters I: the 50 AU Jupiter
• Searching for debris discs in the 30 Myr open cluster IC 4665
• Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation