News - March 2006

2006 March 30

New Discovery!: R. S. McMillan (Lunar and Planetary Laboratory) reports the discovery of a new comet on images taken by M. T. Read on Mar. 26, 2006, in the course of the Spacewatch Survey. A. C. Gilmore (Mt. John) was able to confirm the cometary nature of the 19.5^m object. The first and preliminary orbit for comet P/2006 F4 (Spacewatch) shows perihelion on Apr. 15, 2006, at about 2.4 AU. The comet has a period of about 6.9 years. This is the 33^rd comet for the Spacewatch Survey. (IAUC 8695, subscription required, MPEC 2006-F53)
New astrometry and subsequent identification of prediscovery images of Jan. 10, 2006, by Catalina, lead to a periodic orbit for comet P/2006 F1 (Kowalski). Perihelion occurs on Feb. 6, 2008, at about 4.1 AU. The period is about 10.2 years. Preliminary calculations by S. F. Hönig indicate that the comet was recently perturbed by Jupiter from a 40-year orbit into the current one. It will also experience perturbations in the future, which may shorten the period and perihelion distance. (MPEC 2006-F49, Comets Mailing List)

Further SOHO comets (all named SOHO):

Designation  Group   Discoverer  Notes
C/2006 E2    Marsden R. Matson   27^th member of the Marsden group
C/2006 F3    Marsden T. Hoffman  28^th member of the Marsden group

Official SOHO comets: 1094. (MPEC 2006-F50)

2006 March 29

Further SOHO comets (all named SOHO):

Designation  Group   Discoverer  Notes
C/2006 A4    Kreutz  R. Matson
C/2006 A5    Meyer   T. Hoffman
C/2006 A6    Kreutz  T. Hoffman
C/2006 A7    Kreutz  S. Farmer
C/2006 B2    Kreutz  H. Su
C/2006 B3    Kreutz  R. Kracht
C/2006 B4    Meyer   H. Su      66^th member of the Meyer group

Official SOHO comets: 1092. (MPEC 2006-F43, MPEC 2006-F44)

2006 March 25

E. J. Christensen reports four additional new fragments for comet 73P/Schwassmann-Wachmann. Component K could be detected again. The following table summarises all observed components (the four new ones are in italics):

Designation  Discoverer              Brightness  T: 2006 June
B            Böhnhardt (1995)   11          07.94
C            Böhnhardt (1995)   12.5        06.95
G            Tucker/Christensen      17.5        08.11
H            Kowalski                20          08.29
J            Hill/Christensen        20          08.14
K            Hill/Christensen        22          08.24
L            Hill/Christensen        20          08.35
M            Christensen/Birtwhistle 21          08.28
N            Christensen/Birtwhistle 21          08.30
P            Christensen             20          07.88
Q            Christensen             21          07.74
R            Christensen             20.5        08.20
S            Christensen             21          08.24

(CBET 442, subscription required)

New Discovery!: E. J. Christensen reports his discovery of a new comet on Mar. 23, 2006, in the course of the Mt. Lemmon Survey. The first and preliminary orbit for the 19.5^m comet C/2006 F2 (Christensen) - also aided by prediscovery observations by Spacewatch of Feb. 27 - shows perihelion on Mar. 17, 2006, at about 4.3 AU. The comet has a period of about 44 years. This is the 6^th comet for the Mt. Lemmon Survey and the 10^th for Christensen. (IAUC 8692, subscription required, MPEC 2006-F29)
The first parabolic orbit for comet C/2006 E1 (McNaught) shows perihelion on Dec. 14, 2006, at about 6.1 AU. This is the 24^th comet for McNaught. (IAUC 8691, subscription required, MPEC 2006-F28)

2006 March 24

Upon reobserving the new components of comet 73P/Schwassmann-Wachmann, E. Christensen (Mt. Lemmon Survey) and P. Birtwhistle (Great Shefford) were able to detect two new components, designated M and N, both around 21^m.
```
Designation  Discoverer              Brightness  T
M            Christensen/Birtwhistle 20.8        2006 06 08.28
N            Christensen/Birtwhistle 21.4        2006 06 08.30
```
Both could not detect the new component K. (CBET 439, subscription required, MPEC 2006-F22)
According to a paper by H. H. Hsieh and D. Jewitt (University of Hawaii) which appeared in the March 23 edition of the Science Express (PDF) a new class of comets has been identified in the minor planet main belt - the so-called main belt comets (MBCs). The paper specifically identifies comets 133P/Elst-Pizarro and P/2005 U1 (Read) as such MBCs. Additionally they also detected cometary activity for the minor planet (118401) 1999 RE₇₀, found 1999 by LINEAR.

2006 March 23

New Discovery!: R. A. Kowalski reports his discovery of a new comet on Mar. 21, 2006, in the course of the Mt. Lemmon Survey. After posting on the NEO Confirmation Page the 18.5^m object was confirmed as a comet by E. J. Christensen (Mt. Lemmon) and P. Birtwhistle (Great Shefford). The first and preliminary parabolic orbit for comet C/2006 F1 (Kowalski) shows perihelion in May 2007, at about 1.9 AU. This is the 5^th comet for the Mt. Lemmon Survey. The comet may reach 12^m in 2007. (CBET 438, subscription required, MPEC 2006-F20)

2006 March 16

New Discovery!: R. H. McNaught reports his discovery of a new comet on Mar. 11, 2006, in the course of the Siding Spring Survey. No orbit for the 18^m comet 2006 E1 is yet available. This is the 16^th comet for the Siding Spring Survey. (IAUC 8688, subscription required)

2006 March 10

Four additional fragments have been discovered for comet 73P/Schwassmann-Wachmann.

Designation  Discoverer        Brightness  T
H            Kowalski          20          2006 06 08.29
J            Hill/Christensen  19.8                08.14
K            Hill/Christensen  21.7                08.24
L            Hill/Christensen  19.8                08.35

No fragments brighter than 22^m have been found on the line of variation for 3500". There are now a total of seven fragments. (IAUC 8685, subscription required)

2006 March 02

C. W. Hergenrother (Lunar and Planetary Laboratory) reports that images taken with the Catalina 1.54-m Kuiper telescope (Feb. 24 and 25 UT) and with the Vatican 1.8-m Lennon telescope (Feb. 28.5 UT) show a coma and a tail for the formerly asteroidal object 2006 CK₁₀, which was discovered on Feb. 04, 2006, in the course of the Catalina Sky Survey. E. J. Christensen reports that four Catalina Sky Survey images (Mar. 2.35-2.36 UT) show also a faint coma with an elongation. The 17.5^m comet C/2006 CK₁₀ (Catalina) will pass perihelion on July 2, 2006, at about 1.8 AU. This is Catalina's 30^th comet discovery. (IAUC 8682, subscription required, MPEC 2006-E04)