News - October 1999
10/28/1999
- New Discovery!:
On Oct. 25, 1999, S. Gregory (Stanford University) and J. D. Shanklin (Comet
Section, British Astronomical Association) discovered independently in data of the
LASCO/C3 coronagraph of the SOHO
spacecraft the 90th SOHO comet. Comet C/1999 U2 (SOHO) is not a
member of the Kreutz group and very faint. The orbit indicates a perihelion on Oct.
25, 1999, at about 0.05 AU. (IAUC 7292, MPEC 1999-U29)
10/25/1999
- New Discovery!:
An object, first observed by the LINEAR program
on Oct. 03, 1999, was - after subsequent observations - identified as parabolic and
retrograde. An additional observation was made by E. W. Elst and S. Ipatov in Uccle
(Belgium) on Oct. 18, 1999. In response to enquiries, Elst reported some diffuseness of the
object and a possible, short tail. Further observations by J. Ticha and M. Tichy (Klet, SLK)
and D. Durig (Sewanee, TN, USA) confirmed the diffuse character. The 17m comet
C/1999 T3 (LINEAR) will pass its perihelion on Aug. 29, 2000, at about 5.4 AU. (IAUC
7289, MPEC 1999-U27)
10/21/1999
- The first orbit for comet C/1999 U1 (Ferris) indicates a perihelion already in
August 1998 at about 2.9 AU. If the comet hasn't undergone an outburst that would mean that
it might have been observable nearly the through whole year of 1998 with a brightness of
about 13m - 14m. But it was situated deep in the Southern sky which
isn't yet covered by extensive search programs. (IAUC 7287, MPEC 1999-U19)
-
G. Hahn and C.I. Lagerkvist report in Icarus (The recent orbital history of periodic
Comet P/Lagerkvist (1996 R2). ICARUS, 1999, Vol.140, No.2, pp.462-463) about their
investigations of the orbit of comet P/1996 R2 (Lagerkvist). They integrated 100
orbits centered on this comet 70 years backwards and 200 years forward. It was found out
that this comet (now a member of the asteroid family of the quasi-Hildas) was most likely
transferred into its present orbit in 1990, until then the comet was temporarily captured by
Jupiter. The next 100 years show a stable orbit, after that the comet will be perturbed
by another close encounter with Jupiter.
(CCNet)
10/19/1999
- New Discovery!:
The LONEOS
program reports the discovery of a new comet on Oct. 18, 1999. Comet 1999 U1 is about
17m. No orbit is available yet. (IAUC 7283)
10/16/1999
- Pre-discovery images of comet C/1999 T2 (LINEAR) of Sep. 25, 1999,
(LONEOS) and Oct. 05, 1999, (LINEAR) were found. The first orbit indicates a
perihelion at the end of November 2000 at about 3 AU. So this comet will be visible
for the next years for mid-European observers. It might reach a maximum brightness
of 13m from the middle of 2000 to the middle of 2001. (IAUC 7281, MPEC
1999-T64)
- The comets P/1994 P1 = P/1999 P1 (Machholz 2) and
P/1988 V1 = P/1999 R2 (Ge-Wang) received the periodic comets numbers
141P/Machholz 2 and 142P/Ge-Wang, respectively.
10/15/1999
- New Discovery!:
F. Shelly reports the discovery of the 33th comet on Oct. 14, 1999, by the
LINEAR program. Comet 1999 T2 is
currently at about 16m - 17m. No orbit is available yet. (IAUC 7280)
10/11/1999
- New Discovery!:
Robert H. McNaught (Research School of Astronomy and Astrophysics, Siding Spring Observatory,
Australia) discovered a new 15m comet on images taken by Malcolm Hartley on Oct.
7, 1999. The first and preliminary orbit for comet C/1999 T1 (McNaught-Hartley)
shows a perihelion passage in December 2000 at a distance of about 1.15 AU. The assumption
of average brightness parameters yields an relatively high absolute brightness of about
4.5m, indicating a maximum brightness of about von 6m. The comet will
become observable from mid-Europe not before December 2000, but then ideally placed. (IAUC
7273, MPEC 1999-T42)
- First and raw estimations about the brightness increase of comet 9P/Tempel 1 on
July 4, 2004, when the comet mission
Deep Impact
will fire a 500 kg copper projectile into the comets nucleus, yield an increase from
12m to 5m - 6m. The brightness maximum should be reached
within minutes and may last for several hours, maybe days.
(Cosmic Mirror 152)
10/07/1999
- New orbital elements for comet C/1999 S3 (LINEAR) indicate that it is a
short-periodic comet with a period of about 80 years. The orbit update for comet
C/1999 S2 (McNaught-Watson) changes its perihelion passage to November 1997.
(MPEC 1999-T24, -T25)
10/02/1999
- New Discovery!:
On Sep. 27, 1999, the LINEAR program
discovered an asteroidal object which was (after posting on the NEO Confirmation Page)
identified as a comet by D. Durig (Sewanee, TN, USA) and J. Ticha and M. Tichy (Klet,
SLK). Comet C/1999 S4 (LINEAR) is currently at about 16m. According
to the first orbit it will pass its perihelion in July 2000 at about 0.7 AU! So it
might become a naked-eye object with about 3m in July (unfortunately only
under only moderate visibility conditions for mid-Europe). (IAUC 7276, MPEC
1999-T02)