The Debris Disk Fraction for M-dwarfs in Nearby Young Moving Groups

Abstract

Abstract.I present the first substantial work to measure the fraction of debris disks for M-dwarfs in nearby moving groups (MGs). Utilising the AllW ISE IR catalog, 17 out of 151 MG members are found with an IR photometric excess indicative of disk structure. The M-dwarf debris disk fraction is 6 per cent in MGs younger than 40 Myr, and none are found in the groups older than 40 Myr. Simulations show, however, that debris disks around M-dwarfs are not present above a W ISE W 1 − W 4 colour of ∼ 2.5, making calculating the absolute disk fractions difficult. The debris disk dissipation timescale appears to be faster than for higher-mass stars, and mechanisms such as enhanced stellar wind drag and/or photoevaporation could account for the more rapid decline of disks observed amongst M-dwarfs.

A New M Dwarf Debris Disk Candidate in a Young Moving Group Discovered With Disk Detective

“…The frequency of M dwarf debris disks at varying ages is a subject of intense debate in the literature. The frequency of debris disks around young (≤ 40 Myr) M dwarfs is ∼ 6% (Binks 2016), while the prevalence around older M dwarfs is ≤ 1.3% (Avenhaus et al 2012;Theissen & West 2014). In contrast, debris disks are detected around 32 ± 5% of young A stars with Spitzer /MIPS (Su et al 2006), and around 1 − 6% of old (∼ 670 Myr) Sun-like (F5-K9) stars with Spitzer /MIPS (Urban et al 2012).…”