On the flux of extrasolar dust in Earth's atmosphere

摘要

Micron-size extrasolar dust particles have been convincingly detected by satellites. Larger extrasolar meteoroids (5 - 35 mum) have most likely been detected by ground-based radar at Arecibo and New Zealand. We present estimates of the minimum detectable particle sizes and the collecting areas for both radar systems. We show that particles larger than similar to 10 mum can propagate for tens of parsecs through the interstellar medium, opening up the possibility that ground-based radar systems can detect AGB stars, young stellar objects such as T Tauri stars, and debris disks around Vega-like stars. We provide analytical and numerical estimates of the ejection velocity in the case of a debris disk interacting with a Jupiter-mass planet. We give rough estimates of the flux of large micrometeoroids from all three classes of sources. Current radar systems are unlikely to detect significant numbers of meteors from debris disks such as beta Pictoris. However, we suggest improvements to radar systems that should allow for the detection of multiple examples of all three classes. [References: 86]