Spitzer Constraints on Primordial and Debris Disk EvolutionJohn Carpenter on behalf of the FEPS collaboration

Parameter Space for FEPS and Upper ScoStellar Age (Myr)5330000.1201Stellar Mass (Msun)FEPS (314 + stars)Upper Sco (205 stars)

Disks vs. Stellar Mass at 5 Myr

FEPS: 8m excesses< 1.3% excess (3) for < 100 MyrSee also Silverstone et al. (2006)

FEPS: 24m excesses3 = 12%

24m Excess Fraction vs. Age

70m Excess Fraction vs. Age

Dust temperatures

IRS Dust Temperature vs. Age

Debris Disk ModelsKenyon & Bromley (2005)Terrestrial Planet FormationKuiper Belt disks

Evolution of Hot DustFEPS 8m limit (3)Dominic & Decin (2003)Wyatt et al. (2007)

Evolution of Warm Dust

Evolution of Cool Dust

Gas Dissipation TimescalesPascucci et al. 2006H2H2S IH2Si IIFe II

Gas Dissipation TimescalesPascucci et al. 2006< 0.04 MJup in inner disk for ages 10-100 Myr< 2 Mearth between radius of 10 and 40 AU

SummaryPrimordial disks survive longer around low mass stars

12% solar mass stars with > 12% excess at 24 m for < 300 Myr

Decline in 24 m excess fraction > 300 Myr

Uranus/Neptune-mass planets form by 100 Myr