Solar System
Dynamics &
Planetology
Group 		C/1999 F2 Dalcanton




data set of C/1999 F2

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General description

C/1999 F2 was discovered on 20 March 1999 by J. Delcanton in the Sloan Digital Sky Survey as an apparently cometary object, seven months after perihelion passage. Soon after, G.W. Williams found pre-discovery measurements in archival LINEAR data going back to 18 June 1998 [IAUC 7194, 1999 June 8]. Later, the pre-discovery detection from 15 May 1998 taken by Two Micron All Sky Survey (2MASS) was found.

This comet made its closest approach to Earth on 14 April 1998 (3.923 au), about four months before perihelion.

Solution given below is based on data span over 2.3 yr in a range of heliocentric distances: 4.79 au – 4.719 au (perihelion) – 7.3 au.


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 C1992F2A2-001

Comet C/1999 F2 Dalcanton

number of observations 148
number of residuals 293
data interval 1998 May 15 — 2000 Aug. 29
rms [arcsec] 0.73
orbit quality class 1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT) 19980815.0 = JD 2451040.5
time of perihelion passage (TT) 19980823.988272 ± 0.002572
perihelion distance 4.71880860 ± 0.00001514
eccentricity 0.99863745 ± 0.00001566
argument of perihelion [deg] 352.393463 ± 0.000353
longitude of the ascending node [deg] 210.295764 ± 0.000051
inclination [deg] 56.421004 ± 0.000049
inverse semimajor axis [10-6 au-1] 288.75 ± 3.32

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

data set of C/1999 F1

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/1999 F2. Each density map is given in logarithmic scale presented on the right in the individual panel.
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Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 16930525
time of perihelion passage (TT) 19980824.023182 ± 0.002527
perihelion distance 4.72811386 ± 0.00001507
eccentricity 0.99977816 ± 0.00001569
argument of perihelion [deg] 352.298488 ± 0.000353
longitude of the ascending node [deg] 210.295378 ± 0.000052
inclination [deg] 56.362989 ± 0.000050
inverse semimajor axis [10-6 au-1] 46.92 ± 3.32

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.

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

Epoch (TT) 23070617
time of perihelion passage (TT) 19980824.046090 ± 0.002597
perihelion distance 4.72526742 ± 0.00001504
eccentricity 0.99834836 ± 0.00001569
argument of perihelion [deg] 352.417408 ± 0.000351
longitude of the ascending node [deg] 210.225871 ± 0.000051
inclination [deg] 56.402618 ± 0.000050
inverse semimajor axis [10-6 au-1] 349.53 ± 3.32


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





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