Type
Periodic
Perihelion Date
10 September 2018
Perihelion Distance (q)
1.0
Aphelion Distance (Q)
6.0
Period (Years)
6.5
Eccentricity (e)
0.71
Inclination (i)
32.0
Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 19 January 2019
Michel Giacobini (Nice, France) discovered this comet in Aquarius on 20 December 1900. Ernst
Zinner (Bamberg, Germany) discovered a comet while observing variable stars near Beta Scuti
on 23 October 1913. He described it as about magnitude 10, with a coma 3 arc minutes across
and a tail 30 arc minutes long.
The comet was observed for nearly two months during its discovery apparition. During the latter
days of December 1900, observers estimated the comet's total magnitude as between 10.5 and
11, while the magnitude of the nuclear condensation was about 12. The coma was near one arc
minute in diameter, and no tail was reported. The comet faded as January began and it was last
seen on 16 February.
The comet was recognized as a short-period comet during the discovery apparition, and the
orbital period was ultimately determined as 6.52 years. A prediction was made that it would
return to perihelion during 1907 and that it would be very badly placed for observation. No
searches appear to have been made. The comet was next expected to return to perihelion in
1914, when conditions would make the comet impossible to recover. As later calculations
revealed, the orbital period in 1900 was actually 6.46 years, so that the prediction for the
apparent 1914 return was in error by about six months.
The comet was missed at the unfavorable 1920 return, but was next recovered on 16 October
1926 at Bergedorf. The precise position indicated the prediction for this return had been in error
by only 5 days. The comet reached a maximum brightness of 11 and a maximum tail length of
2 arc minutes.
The comet has been seen at every return since discovery, except for the very unfavorable 1953
return. The 1946 apparition was especially noteworthy as the comet passed only 0.26 AU from
Earth in late September. The comet was then near magnitude 7, making this the brightest
appearance since its discovery. Interestingly, the comet experienced an unexpected outburst in
brightness which caused it to reach magnitude 6 during the first days of October. Following the
missed return in 1953, the comet returned in 1959. Unexpected brightness outbursts were
detected on 31 August, 23 September and 24 October, each increasing the comet's brightness
by about one-half magnitude. Ultimately, the comet's maximum brightness reached 7 during
1959 and, at one point, the tail was one degree long.
This comet is especially noteworthy as it is one of a small number of comets that can produce
very spectacular meteor showers under the right conditions. The meteor display is variously
referred to as the Draconids, October Draconids, and the Giacobinids. The meteor shower occurs
around 9 October of each year, but is usually unrecognizable; however, meteor storms occurred
in 1933 and 1946 which produced several thousand meteors within an hour at maximum.
Close approaches to planets:
•
0.88 AU from Earth on 15 December 1900 (contributed to comet's first discovery)
•
0.51 AU from Earth on 14 November 1913 (contributed to comet's seond discovery)
•
0.26 AU from Earth on 20 September 1946
•
0.93 AU from Jupiter on 19 January 1958 (decreased perihelion distance from 0.99 AU to
0.94 AU and decreased orbital period from 6.56 to 6.42 years)
•
0.35 AU from Earth on 8 November 1959
•
0.58 AU from Jupiter on 23 September 1969 (increased perihelion distance from
•
0.93 AU to 0.99 AU and increased orbital period from 6.41 to 6.52 years)
•
0.93 AU from Earth on 24 July 1972
•
0.47 AU from Earth on 6 September 1985
•
0.85 AU from Earth on 27 November 1998
•
0.39 AU from Earth on 11 September 2018
•
0.37 AU from Jupiter on 14 February 2029 (will increase perihelion distance from 1.01 AU
to 1.07 AU and increase orbital period from 6.53 to 6.70 years)
•
0.53 AU from Earth on 5 September 2031
Date
10x10 mag
Error
Kphot mag
Coma '
16-Apr-18
17.59
0.02
17.1
0.3
24-Jun-18
14.03
0.01
11.9
1.3
07-Jul-18
13.55
0.09
10.4
2.4
14-Jul-18
13.09
0.01
10.4
4.9
03-Aug-18
11.93
0.01
8.5
7.4
08-Sep-18
11.08
0.01
7.0
9.5
06-Oct-18
12.42
0.03
9.3
3.1
11-Oct-18
12.77
0.02
9.4
2.0
14-Oct-18
13.15
0.02
9.8
1.9
20-Oct-18
13.59
0.02
10.4
2.3
18-Nov-18
15.01
0.01
11.6
1.0
09-Dec-18
15.52
0.03
13.4
0.7
29-Dec-18
15.75
0.06
13.5
0.8
02-Jan-19
15.78
0.02
12.9
0.7
12-Jan-19
16.10
0.03
13.4
0.7