Monday, December 5, 2011

C/2011 W3 (LOVEJOY) - Kreutz Sungrazing Comet

Cbet nr.2930, issued on 2011, December 02, announces the discovery of a new comet (discovery magnitude 13) by Terry Lovejoy on three CCD images obtained each on Nov. 27.7 and 29.7 UT with a Celestron 8 0.20-m f/2.1 Schmidt-Cassegrain reflector (+ QHY9 camera). The new comet has been designated C/2011 W3 (LOVEJOY).

The comet appears to be a Kreutz sungrazer, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach. 

This is the first ground-Based discovery of a Kreutz Sungrazing Comet since 1970!!

We performed some follow-up measurements of this object remotely from the GRAS Observatory (Australia - MPC Code  E03) on 2011, December 04.7 through a 0.10-m f/5 reflector + CCD.

Our image of comet C/2011 W3 (LOVEJOY):



Below you can see an animation showing the fast movement of the comet in the sky. Each frame is a 30-second exposure. Click here or on the thumbnail for a bigger version.




M.P.E.C. 2011-X16 assignes the following preliminary orbital elements to comet C/2011 W3: T 2011 Dec. 15.99; e= 1.0; Peri. = 57.14; q = 0.005 AU; Incl.= 135.93

The comet is now rapidly brightening but seems intrinsically faint. It may not survive its close perihelion  (at 0.0058936AU, which is a little over 1.2 solar radii) passage on December 16th that will bring it within 880,000 km of the center of the Sun (comet C/2011 W3 will pass just 180,000 km from the Sun’s surface).

The following ephemeris (from Cbet 2930) assumes H = 14.0 and 2.5n = 8.  Note that the rate of brightness  increase is highly uncertain.

Date    TT        R. A. (2000) Decl.     Delta      r     Elong.    Mag
2011 12 06    15 35.96   -47 53.6    0.708    0.505    29.3   11.4
2011 12 07    15 53.78   -46 18.1    0.716    0.470    26.5   11.2
2011 12 08    16 10.34   -44 31.1    0.727    0.434    23.8   10.9
2011 12 09    16 25.59   -42 34.2    0.742    0.397    21.1   10.6
2011 12 10    16 39.54   -40 28.8    0.759    0.358    18.5   10.3
2011 12 11    16 52.22   -38 15.8    0.780    0.316    15.8   10.0
2011 12 12    17 03.68   -35 55.6    0.804    0.272    13.1   9.5
2011 12 13    17 13.96   -33 27.7    0.833    0.223    10.4   8.9
2011 12 14    17 23.07   -30 48.9    0.869    0.169     7.7   8.0
2011 12 15    17 30.86   -27 50.3    0.914    0.105     4.7   6.5
2011 12 16    17 32.18   -23 05.4    0.989    0.006     0.2  -3.4
2011 12 17    17 16.52   -25 17.7    0.919    0.104     4.9   6.4
2011 12 18    17 10.86   -27 27.6    0.873    0.169     7.8   8.0
2011 12 19    17 06.90   -29 31.8    0.835    0.223    10.5   8.9
2011 12 20    17 03.78   -31 35.1    0.802    0.271    13.0   9.5
2011 12 21    17 01.19   -33 39.8    0.771    0.316    15.4   9.9

Extreme care is needed due to the comet's small solar elongation angle and close proximity to the Sun in the sky.

Congrats to Terry Lovejoy his third comet discovery!! On comets-ml mailing list you can read the full discovery  story written by Terry himself.

By Ernesto Guido, Giovanni Sostero & Nick Howes

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