An apparently asteroidal object of 16 mag was found by R.D. Cardinal with the 0.5m-reflector at the University of Calgary on Oct. 1, 2008 in the constellation Camelopardalis, revealing its cometary nature on detailed observations. Comet C/2008 T2 (Cardinal) showed a round 12" coma of total magnitude 14.5 and a fan-shaped tail at p.a. 240-330°. The comet will pass perihelion in June 2009 and may reach a maximum brightness of 8 mag (IAUC 8993 / MPEC 2008-V52). Until March 2009 it remains at high northern declinations (passing Polaris very closely on Dec. 5), being an all-night object. From the beginning of January 2009 (12 mag) until it disappears above the mid-European western horizon in mid-May (8.5 mag) it moves through the constellations Cassiopeia, Camelopardalis, Perseus, Auriga and Gemini. The apparent coma diameter should reach a maximum of 5', the apparent tail length a maximum of about 0.3°.
Despite becoming visible even in binoculars only 15 observations by 6 members of the German Comet Section were received. Additional 110 international observations could be used for the analysis. These show a very steady increase in brightness since the last days of December 2008, described very well by the formula
m = 6.0 mag + 5×log D + 14.5×log ryielding a maximum brightness of 8.4 mag in mid-June, at a time when the comet was no longer visible from mid-European latitudes. The observations at the end of October 2008 are enigmatic. On a first look these could be marked as erroneous observations; however, three different observers estimated very similar brightnesses.
Total Brightness and Coma Diameter
Until the end of the year 2008 the coma diameter was only 0.4' (45.000 km), increasing slowly to 2' (125.000 km) until March, then more rapidly to 5' (380.000 km) at the end of May 2009, eventually peaking at 5.5' (450.000 km) near perihelion. After perihelion it shrunk to 1.5' at the start of October. The coma was strongly condensed (DC 6-7) until mid-January 2009. Thereafter it became more diffuse, estimated to be only DC 1 in mid-May. The published post-perihelion observations did not list any DC-value. No tail was observed.
Andreas Kammerer
