Heliocentric magnitude of comet C/2014 Q2 (Lovejoy)

Comet C/2014 Q2 (Lovejoy) Heliocentric magnitude versus log r 

This plot of the heliocentric magnitude versus log r shows that a large difference in the brightening of comet C/2014 Q2 (Lovejoy) pre perihelion compared to post perihelion The comet is expected to fade at a slower rate departing the sun than it brightened as it approached the sun. The general shape of this plot is similar to the plot of logarithmic slope of Afrho. R band photometry data from the Cometas-Obs group observers was reduced and normalized to zero phase by the relation:

mH = m - 5 log delta + 2.5 log phi
mH is heliocentric magnitude
m is R band magnitude at aperture of 10,000 km
where delta is earth distance
2.5 log phi is magnitude of the phase function


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

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Blaauw, Rhiannon C.; Suggs, Robert M.; Cooke, William J., Dust Production of Comet 21P/Giacobini-Zinner using Broadband Photometry, Meteoritics & Planetary Science, Volume 49, Issue 1, pp. 45-51 (2014)

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