C/2007 N3 (Lulin)

Discovery:

This object was initially described as an asteroidal object, when found by Quanzhi Ye (Sun Yat-sen University, Guangzhou, China) on three images obtained by Chi-Sheng Lin (Institute of Astronomy, National Central University, Jung-Li, Taiwan) on 2007 July 11. Lin had acquired the images using the 41-cm Ritchey-Chretien and a CCD camera at Lulin Observatory (Nantou, Taiwan). The magnitude was given as 18.9. Several confirming observations were obtained; however, on July 17, J. Young (Table Mountain Observatory, California, USA) noted a coma 2-3" across, with a bright central core.

 

Historical Highlights:

Using 76 positions spanning the period of 2007 July 11 to 17, B. G. Marsden calculated a parabolic orbit with a perihelion date of 2009 January 7.35. Even more interesting was the perihelion distance of 1.19 AU. Marsden revised his calculations a couple of days later. Using 89 positions spanning the period of July 11 to 19, he determined the perihelion date as January 14.95 and the perihelion distance as 1.24 AU.

 

The comet will pass 0.41 AU from Earth on 2009 February 24.

The comet steadily brightened during the last months of 2008. It was near magnitude 11.0 at the beginning of July, 10.5 at the beginning of August, 10.0 at the beginning of September, and 9.5 at the beginning of October. As the comet approached evening twilight, it was observed by a few observers at low altitude. Chris Wyatt (Australia) saw the comet with his 25-cm reflector on October 18. He gave the magnitude as 8.1 and said the moderately condensed coma was 12' across. J. J. Gonzalez (Spain) saw the comet on October 18 and 19, using 25x100 binoculars, when its altitude was only 7-8 degrees. He gave the magnitude as 8.3 on the last date, while the moderately condensed coma was 4' across. Con Stoitsis (Australia) saw the comet with his 20-cm Dobsonian on October 20. He gave the magnitude as 9.0 and said the moderately condensed coma was 4.5' across. D. A. J. Seargent (Australia) saw the comet for the final time before solar conjunction on October 27. Using 25x100 binoculars, he gave the magnitude as 8.1 and the coma diameter as 5'.

 

Following solar conjunction, the comet was picked up in the morning sky by Gonzalez on December 21. Astronomical twilight was just beginning, while the comet was 7 degrees above the horizon. His 25x100 binoculars revealed a magnitude of 7.6, while the moderately condensed coma was 2.5' across. Based on this observation, the comet's maximum magnitude in late February might reach magnitude 4.