155P/Shoemaker (0155P)
TRY AGAIN 2035
Type: Periodic
Perihelion date: 14 November 2019
Perihelion distance (q): 1.8
Aphelion distance (Q) : 11.4
Period (years): 16.9
Eccentricity (e): 0.73
Inclination (i): 6.4
JPL orbit diagram
COBS lightcurve
Caroline and Eugene Shoemaker (Palomar Observatory, California, USA) discovered
this comet on a photographic plate obtained with the 0.46-m Schmidt telescope on 10
January 1986. They estimated the magnitude as 10 (although it was later revised to
12) and described the comet as moderately condensed, with a short tail. The comet
was confirmed by B. A. Skiff (Lowell Observatory, Anderson Mesa Station, Arizona,
USA) on 12 January. He gave the magnitude as 13 and noted the short tail extended
toward PA 86°.
The first orbit was calculated by B. G. Marsden based on 14 positions gathered during
the period of 10-20 January 1986. He noted that the comet was moving in an elliptical
orbit with a perihelion date of 20 December 1985 and had a period of 15.3 years. He
added, "The revolution period is still rather uncertain." Marsden revised his orbit on 31
January 1986, giving the perihelion date as 19 December and the period as 16.34
years. Ultimately, the perihelion date proved to be 18 December, while the period was
16.91 years.
During the apparition of 1985-1986, several observers provided magnitude estimates
of 13 shortly after mid-January. The comet was followed during the next few months
as it steadily faded and was last detected with the Spacewatch telescope (Steward
Observatory, Arizona, USA) on 14 May.
The comet was independently recovered on 9 September 2002 by T. Oribe (Saji
Observatory) and on 12 September by A. Nakamura (Kuma Kogen Observatory,
Japan). The magnitude was then given as 18.0 and 18.6, respectively. Prediscovery
images were subsequently found on photographs obtained by T. Seki (Geisei, Japan)
on 4 and 7 September . The comet was well observed at this apparition and
numerous observers indicated the brightness attained a maximum value between 13
and 14.
Observations (VEMag = visual equivalent magnitude)
Date
10x10 mag
Error
VEmag
Coma '
05-Oct-19
17.17
0.04
16.0
0.5
12-Oct-19
15.63
0.01
15.2
0.4
29-Oct-19
16.39
0.04
14.7
0.6
30-Nov-19
16.52
0.01
15.3
0.6
09-Dec-19
16.65
0.02
15.6
0.5
22-Dec-19
16.66
0.02
15.6
0.4
22-Dec-19
16.66
0.02
15.6
0.5
29-Dec-19
16.66
0.02
15.4
0.5
05-Jan-20
16.52
0.04
15.2
0.5
18-Jan-20
16.78
0.02
14.8
0.8
25-Jan-20
16.82
0.02
15.6
0.6
03-Feb-20
16.74
0.03
14.8
0.6
16-Feb-20
16.72
0.01
15.0
0.7
19-Mar-20
17.86
0.05
15.7
0.7
29-Mar-20
18.32
0.06
17.1
0.4