Reports from Geisei Observatory<July 20, 2001>

• LINEAR(2001 A2-b)breaking up?
The photograph by the 60cm telescope presented here on July 14 did not show any peculiarities to the nucleus. At midnight on July 19 I noticed that the coma was smaller and fainter in the 20cm refractor at 60x. The total magnitude was about 6.5. A long-exposure (12 minutes) photograph by the 60cm telescope showed the nucleus B being formed of three nuclei (or fragments). The following PA and distance from the nucleus B were obtained.

                PA    distance    m2
Second nucleus  225o     5"      14m
Third nucleus   315o    10"      13m

I observed these three bright nuclei in the telescope. The first one seems to be the nucleus B. A new nucleus was split from the nucleus B preceding it. The nucleus B looks further split into two.

  2001 U.T       R.A(2000)    Decl.     m2(nucleus)
  July 19.69340  21 47 39.2  +18 03 05  12
  July 19.69340  21 47 38.8  +18 03 02  14
  July 19.69340  21 47 38.6  +18 03 16  13

These splinter nuclei may disappear soon. The comet itself will deteriorate rapidly. The comet was observed at 22.00 on July 20. The nucleus did not appear to be split into three; rather elongated in a direction of splitting.
LINEAR (1994 S4), which broke up and disappeared, showed the nucleus stretched like a string before the breakup. Are we seeing now a sign of the impending destruction of this comet?


C/2001 A2(LINEAR) broken up 3.10 am on July 20, 2001 12-minute exposure 60cm f/3.5 reflector Tsutomu Seki at Geisei Observatory