C/2011 L4 (PANSTARRS)
DEPARTED
Type: Hyperbolic
Perihelion date: 10 March 2013
Perihelion distance (q): 0.3
Aphelion distance (Q) : n/a
Period (years): n/a
Eccentricity (e): 1.00
Inclination (i): 84.2
JPL orbit diagram
COBS lightcurve
Richard Wainscoat, Institute for Astronomy, University of Hawaii, reported to the MPC
that an object discovered on four CCD images taken with the 1.8-m "Pan-STARRS 1"
telescope at Haleakala on 6 June 2011 appeared to show slight non-stellar
appearance; three follow-up 30-s r-band exposures were then acquired by M. Micheli
and Wainscoat with the Canada-France-Hawaii Telescope on Mauna Kea (queue
observer Lisa Wells) on 7 June, showing that a coma is definitely visible with a subtle
hint of a faint tail towards p.a. 60 deg. After posting on the NEOCP astrometrists
confirmed the cometary nature.
Visual observations began in March 2012, when the comet was a stellar 14th
magnitude, but by May it had developed a coma, and it was around 12th magnitude
by mid year. It continued brightening relatively quickly and by September was 10th
magnitude. Some observers reported an outburst in August, but this was not
apparent in the mean light curve.
It was recovered after solar conjunction on 24 December by Alexander Amorim, when
it was magnitude 8.1 in his 0.18m reflector. It soon became clear that the rate of
brightening had slowed. By 2013 February it had reached 5th magnitude. It
continued brightening and by the end of the first week of March had reached 0th
magnitude according to observations by Marco Goiato.
Nicolas Biver comments that it is one of the dustiest comets observed, with
disproportionately high dust compared to its water vapour sublimation rate.
Observations (VEMag = visual equivalent magnitude)
Date
10x10 mag
Error
VEmag
Coma '
28-Jan-13
8.94
0.03
5.9
2.1
30-Jan-13
8.78
0.03
5.0
2.3
02-Feb-13
8.87
0.02
5.8
2.0