C/1997 P2 Spacewatch

Solar System
Dynamics &
Planetology
Group

General description

Comet C/1997 P2 was discovered 2.5 weeks before perihelion passage and four days after its discovery made its closest approach to Earth on 16 August 1997 (3.26 au). Comet was observed 49 days (0.13 yr) in a narrow range of heliocentric distances: 4.267 au – 4.264 au (perihelion) – 4.272 au.

C/1997 P2 passed close to Jupiter six months before perihelion passage (0.652 au, 25 February 1997).

Figure caption: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line — the moment of perihelion passage.

SSDP Cometary Note C1997P2A5-001

Comet C/1997 P2 Spacewatch

number of observations	95
number of residuals	184
data interval	1997 Aug. 12 — 1997 Sep. 30
rms [arcsec]	0.59
orbit quality class	2b

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	19970820.0	= JD 2450680.5
time of perihelion passage (TT)	19970830.305268	± 0.743940
perihelion distance	4.26460692	± 0.00106347
eccentricity	1.02825332	± 0.00012512
argument of perihelion [deg]	24.352136	± 0.128813
longitude of the ascending node [deg]	302.929810	± 0.010070
inclination [deg]	14.592497	± 0.007105
inverse semimajor axis [10^-6 au^-1]	-6625.07	± 32.33

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/1997 P2. Each density map is given in logarithmic scale presented on the right in the individual panel. Notice large dispersion of these VCs (poor quality orbit).
The same figure in the new window

Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	16940120
time of perihelion passage (TT)	19970914.383404	± 0.774567
perihelion distance	4.21862723	± 0.00125799
eccentricity	1.00005882	± 0.00005806
argument of perihelion [deg]	25.983973	± 0.133742
longitude of the ascending node [deg]	303.456441	± 0.009622
inclination [deg]	14.535008	± 0.007491
inverse semimajor axis [10^-6 au^-1]	-13.94	± 13.77

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here (data format), i.e. before entering the planetary zone.

Figure caption: Six 2D-projections of the 6D space of future swarm (5001 VCs) of C/1997 P2. Each density map is given in logarithmic scale presented on the right in the individual panel. Notice large dispersion of these VCs (poor quality orbit).
The same figure in the new window

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT)	22780320
time of perihelion passage (TT)	19970825.634391	± 0.748724
perihelion distance	4.24753952	± 0.00110948
eccentricity	1.00982224	± 0.00013216
argument of perihelion [deg]	24.448151	± 0.126797
longitude of the ascending node [deg]	302.238093	± 0.007861
inclination [deg]	14.616409	± 0.006823
inverse semimajor axis [10^-6 au^-1]	-2312.45	± 31.63