News - March 2005

2005 March 31

With more astrometry the revised orbit for comet C/2005 E2 (McNaught) shows a perihelion at about 1.5 AU in February 2006. The comet may then reach 9^m but for mid-European observers it will remain below 20 degrees altitude in the evening sky. (MPEC 2005-F54)

2005 March 22

A new orbit indicates that comet P/2005 E1 (Tubbiolo) is periodic with a period of about 20 years. (MPEC 2005-F37)
Further SOHO comets: C/2005 C2 (SOHO) (H. Su) and C/2005 C3 (SOHO) (X. Leprette) are members of the Kreutz group. C/1997 B4 (SOHO) (R. Kracht), C/1997 V7 (SOHO) (R. Kracht) and C/2005 C4 (SOHO) (R. Kracht) are not members of a known comet group. C/1996 V2 (SOHO) (R. Kracht) is the 20^th member of the Marsden group and C/2005 C1 (SOHO) (H. Su) the 53^rd member of the Meyer group. Official SOHO comets: 914. (MPEC 2005-F31, MPEC 2005-F32)

2005 March 16

New Discovery!: R. H. McNaught, Jr. (Siding Spring) reports his discovery of a new comet in the course of the Siding Spring Survey on March 12, 2005. After posting the 16^m comet on the NEO Confirmation Page A. C. Gilmore and P. M. Kilmartin (Mt. John Obs.) were able to confirm the discovery. The first and very preliminary orbit for comet C/2005 E2 (McNaught) shows a perihelion at about 3.0 AU in April 2006. The comet may then reach 12^m. This is the 6^th comet discovery by the Siding Spring Survey. (IAUC 8494 subscription required, MPEC 2005-E84)
Two further SOHO comets. C/2005 E3 (SOHO) is a Kreutz group comet, found by M. Oates. C/2005 E4 (SOHO) was found by R. Kracht and is a member of the Marsden group. B. G. Marsden (CfA) reports that this comet is likely identical with the Marsden group comet C/1999 N5 (SOHO) and he provides a tentative linking of both objects. Furthermore he has integrated the orbits of those two comets backwards until the perihelion passage of 1993, which showed a close agreement. This indicates that both comets originated from a split in 1993. It is now expected that the bright Marsden group comet C/1999 U2 (SOHO) will return in October 2005, if the assumption is correct that it also originated at the above mentioned splitting. (IAUC 8494 subscription required, MPEC 2005-E87)

2005 March 07

New Discovery!: A. F. Tubbiolo reports his discovery of a new comet in the course of the Spacewatch survey on Mar. 3, 2005. After posting the object on the NEO Confirmation Page A. Fitzsimmons, S. Lowry, and C. Snodgrass (Faulkes Tel. North, Haleakala) and M. Tichy and J. Ticha (Klet) were able to confirm the cometary nature. The first and very indeterminate parabolic elements for the 20^m comet C/2005 E1 (Tubbiolo) indicate a perihelion in Nov. 2006, at about 1.7 AU. The comet might then reach 12^m. This is the 27^th comet discovery by Spacewatch. (IAUC 8491 subscription required, (MPEC 2005-E25)
Several southern hemisphere observers report that comet C/2005 A1 (LINEAR) has already brightened to 8^m. The comet should brighten slightly over the coming weeks. A recent image by Mike Mattiazzo (Australia) shows a short tail and a large and faint outer coma. (Comet Observations Mailing List, Comets Mailing List)

2005 March 03

Michael Jäger (Austria) was able to rediscover component A of comet 141P/Machholz with a 20-cm Schmidtcamera + CCD. Images taken on Feb. 28, Mar. 01, and 02, 2005, showed the component about +0.5 days distant from the prediction. Searches for component D revealed nothing. The comet was about 12^m but only 5° above the horizon. The comet will become fainter but also rises in the evening sky. Astrometry and photometry is strongly encouraged. (private comm.)

2005 March 01

Another non-group SOHO comet: C/2005 D1 (SOHO), found by H. Su, is not a member of a known comet group. Due to the short arc the orbit solution is not unambiguous. Official SOHO comets: 905. (MPEC 2005-E01)