A survey on the distant activity of short period comets

Abstract

Aims. The aim of this paper is to build up an inventory of observations of short period comets (SPCs) far from the Sun, and perform an analysis of general properties of the family, investigating the link between distant activity and present and historical orbital parameters. Methods. We gathered all the data available in the literature (as per June 2009) on SPCs ground-based and space observations at heliocentric distance r h > 3 AU. We analyzed the occurrence of distant activity with respect to: position on orbital branch, present orbital parameters (in particular the perihelion distance q), and their recent variations.Results. There is no sharp cut-off at any heliocentric distance, beyond which the cometary activity fades and only bare nuclei are observed. SPCs are more likely to be active post-perihelion than pre-perihelion: among a dataset of 90 comets (for which a heliocentric distance of analysis has been unequivocally established), 59% of the comets observed post-perihelion were detected as active targets, while only 22% of the comets observed pre-perihelion were active. There is a weak trend of comets with increasing perihelion distance to be more likely active at large heliocentric distance: among comets with q < 1.5 AU, only 5 out of 18 comets (28%) have been reported as active at large heliocentric distance, while among those with q > 3 AU, 14 out of 16 comets (88%) have been classified as active. A much less clear trend has been observed for distant cometary activity with semi-major axis a. No apparent appreciable link of a recent (or secular) increase of the perihelion temperature ΔT (due to a rapid decrease in the perihelion distance) with the present degree of distant activity has been observed.

The persistent activity of Jupiter-family comets at 3–7AU

“…With better confidence, we find that for many comets activity has ceased by f ≈ 140 • . Similar findings on the persistent post-perihelion activity were found by Mazzotta Epifani et al (2009), andFerrín (2010). No comet in our survey is active between f = −180 • and −125 • .…”

“…The activity of short-period comets has also been examined by Mazzotta Epifani et al (2009). They searched the literature for optical and infrared observations of short-period comets (Jupiter-family, Encke type, and Halley type) at r h > 3 AU.…”

Evolution of Cometary Dust Particles to the Orbit of the Earth: Particle Size, Shape, and Mutual Collisions

“…We distributed the true anomalies as the number density of ejected dust particles becomes a function of heliocentric distance following the observed dust ejection efficiency change (Ishiguro et al 2007;Mazzotta Epifani et al 2009;Hanayama et al 2012). Where N (r h ) denotes the initial number density of ejected particles on the given cometary orbit in cm −3 , and r h denotes the heliocentric distance in au, we distributed the particles as:…”

A study of the distant activity of comet C/2006 W3 (Christensen) withHerscheland ground-based radio telescopes

“…Direct imaging shows that distant activity is a general property of cometary nuclei (e.g., Mazzotta Epifani et al 2009). It is attributed to the sublimation of hypervolatile ices, such as CO or CO 2 , or to the release of volatile species trapped in amorphous water ice during the amorphous-to-crystalline phase transition (Prialnik et al 2004).…”