Logarithmic slope of Afrho and Dust production of comet C/2014 Q2 (Lovejoy) pre and post perihelion

Comet C/2014 Q2 (Lovejoy)  Logarithmic slope pre and post perihelion

Dust production of comet C/2014 Q2 followed a logarithmic slope (gamma ) of 4.695 with respect to heliocentric distance prior to perihelion. After perihelion the logarithmic slope changed and is smaller. I expect  that with additional data points post perihelion value of logarithmic slope will be better determined.  
The logarithmic slope can be used to estimate value at perihelion as was done on comet comet 21P/Giacobini-Zinner for a study to better constrain meteor stream forecasts for the Draconids. (Blaauw, Suggs, and Cooke 2012) This study found a similar value of logarithmic slope for comet 21P. They note that a post perihelion value of logarithmic slope for 21P by Pittichova et. al, 2008 was also less. This reduction in the logarithmic slope post perihelion is also evident in photometry results. To determine logarithmic slope, Afrho measures need to be normalized to zero phase by dividing by the phase function. I used Dave Schleicher's phase function. I 

Thanks to the following observers for their data contributions who are credited as follows: 213 Montcabrer, Ramon Naves y Montse Campas; 232 Masquefa, Esteban Reina; 939 Rodeno, Julio Castellano; A02 Cal Maciarol Mòdul 8, Josep Lluís Salto; A06 Mataro, Esteve Cortés y Fernando García; B20 Observatori Carmelità, Josep María Aymamí; B74 Santa Maria de Montmagastrell, Josep María Bosch; B96 Brixiis Observatory, Erik Bryssinck; C23 Olmen, Alfons Diepvens; C35 Terrassa, José Aledo; C86 Blanes, Josep Gaitan; C90 Vinyols, Luís Tremosa; D90 GRAS - Moorook observatory; G39 ROAD, San Pedro de Atacama; G68 Sierra Stars Observatory, Markleeville; H06 GRAS remote telescope; H47 Vicksburg, Charles Bell; I72 Carpe-Noctem, José Luís Martín Velasco; I88 Fuensanta, José Carrillo; I99 Blanquita, Fernando Limón; J01 Cielo Profundo, Juan José González Díaz; J24 Altamira, José Francisco Hernández; J38 Faustino García Cuesta; J67 La Puebla de Vallbona, Enrique Arce; K14 Sencelles, Mario Morales; Q62 Siding Spring; V03 Carlos Labordena Barceló; X18 CArlos Perelló; Z73 Nuevos Horizontes, Jesús Delgado y Josefa Peña; Z74 Francisco Soldán; Z77 Osuna, José María Fernández

References:

Dust Production of Comet 21P/Giacobini-Zinner using Broadband Photometry by Rhiannon C. Blauuw, Robert M. Suggs and William J. Cooke, Meteoritics & Planetary Science 49, Nr 1, 45–51 (2014)

Blauuw- Dynetics Technical Services/MITS Huntsville, AL 35812
Suggs and Cooke - Meteoroid Environment Office/EV44/NASA Mar shall Space Flight Center, Huntsville, AL

The paper by Blauuw, Suggs and Cooke, who work at NASA Marshall Space Center, is open access in the public domain on the NASA technical report server at the following link;
http://ntrs.nasa.gov/…/n…/casi.ntrs.nasa.gov/20130013031.pdf