Eccentric debris disc morphologies – I. Exploring the origin of apocentre and pericentre glows in face-on debris discs

ABSTRACT The location of surface brightness maxima (e.g. apocentre and pericentre glow) in eccentric debris discs are often used to infer the underlying orbits dust planetesimals that comprise disc. However, there is a misconception have higher densities at thus necessarily exhibit glow long wavelengths. This arises from expectation slower velocities lead ‘pile up’ dust, which fails account for greater area over spread apocentre. Instead we show with theory by modelling three different regimes morphology distributions face-on strongly dependent on their eccentricity profile (i.e. whether this constant, rising, or falling distance). We demonstrate shorter wavelengths classical effect remains true, whereas longer can either glow. additionally same disc produce depending observational resolution. Finally, approach interpreting using line only valid under an extremely limited set circumstances, unlikely be met as observations become increasingly better resolved.