Faint debris disk peering through superflare light echo

Abstract

We present the detectability of strong mid-infrared (MIR) light echoes from faint debris disks illuminated by bright superflares of M-dwarf stars. Circumstellar dust grains around an M-dwarf star are simultaneously heated by superflare radiation. One can thus expect their re-emission in the MIR wavelength regime. According to our model calculations for the Proxima Centauri system, the nearest M-dwarf star system, thermal emission echos from an inner ($r<1\mathrm{au}$) debris disk with a total mass down to that of the solar system's zodiacal dust are expected to emerge at wavelengths longer than $\sim 10\mu \mathrm{m}$ with a strength comparable to or greater than a white-light superflare. Also, observable echos from inner- ($r\lesssim 0.5\mathrm{au}$) debris disks irradiated by energetic ($\gtrsim 10^{33.5}\mathrm{ergs}$) superflares of nearby ($D<3\mathrm{pc}$) M-dwarfs are expected. Our simulation results indicate that superflare monitoring using high-speed optical instruments like OASES and its prompt follow-up using ground-based MIR instruments, such as TAO/MIMIZUKU, can detect these MIR light echoes from debris disks around solar neighborhood flare stars.

11 pages, 5 figures, ApJL accepted

References in corpus (7)

• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• Amateur telescopes discover a kilometre-sized Kuiper belt object from stellar occultation
• ALMA Discovery of Dust Belts Around Proxima Centauri
• Hot exozodiacal dust: an exocometary origin?
• Organized Autotelescopes for Serendipitous Event Survey (OASES): design and performance
• Detectability of optical transients with timescales of sub-seconds