| Parameter |
Value |
| Designation |
C/2002 F1 (Utsunomiya) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2002-04-22T21:33:43.323840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:15Z |
| Obs used |
161 |
| NEO |
- |
| M1 |
10.600 |
| K1 |
18.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2002-04-05.0000000 |
| e |
0.99953997 |
| q (au) |
0.438299 |
| a (au) |
952.755523 |
| i (deg) |
80.876930 |
| Ω (om, deg) |
289.029545 |
| ω (w, deg) |
125.900029 |
| M (ma, deg) |
359.999400 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.274 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.274 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.973 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2002-03-20 |
2002-04-04 |
-4.1418 |
-0.069 |
| 2002-04-04 |
2002-04-14 |
+15.8305 |
+4.380 |
| 2002-04-14 |
2002-04-22 |
-15.9612 |
-5.633 |
| 2002-04-23 |
2002-06-02 |
-3.3496 |
-1.321 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
19:05:45.31 |
-88:04:30.5 |
HIP 97658 |
27.69 |
| 2026-06-01 12:00 |
19:04:43.44 |
-88:04:51.1 |
HIP 97658 |
28.31 |
| 2026-06-02 00:00 |
19:03:40.84 |
-88:05:11.3 |
HIP 97658 |
28.92 |
| 2026-06-02 12:00 |
19:02:37.53 |
-88:05:31.1 |
HIP 92824 |
29.51 |
| 2026-06-03 00:00 |
19:01:33.50 |
-88:05:50.5 |
HIP 92824 |
29.75 |
| 2026-06-03 12:00 |
19:00:28.77 |
-88:06:09.6 |
HIP 92824 |
30.00 |
| 2026-06-04 00:00 |
18:59:23.34 |
-88:06:28.2 |
HIP 92824 |
30.25 |
| 2026-06-04 12:00 |
18:58:17.23 |
-88:06:46.5 |
HIP 92824 |
30.51 |
| 2026-06-05 00:00 |
18:57:10.44 |
-88:07:04.3 |
HIP 92824 |
30.77 |
| 2026-06-05 12:00 |
18:56:02.99 |
-88:07:21.7 |
HIP 92824 |
31.04 |
| 2026-06-06 00:00 |
18:54:54.87 |
-88:07:38.7 |
HIP 92300 |
30.89 |
| 2026-06-06 12:00 |
18:53:46.11 |
-88:07:55.3 |
HIP 92300 |
30.57 |
| 2026-06-07 00:00 |
18:52:36.72 |
-88:08:11.5 |
HIP 92300 |
30.28 |
| 2026-06-07 12:00 |
18:51:26.70 |
-88:08:27.2 |
HIP 92300 |
29.99 |
| 2026-06-08 00:00 |
18:50:16.07 |
-88:08:42.5 |
HIP 92300 |
29.72 |
| 2026-06-08 12:00 |
18:49:04.84 |
-88:08:57.3 |
HIP 92300 |
29.47 |
| 2026-06-09 00:00 |
18:47:53.03 |
-88:09:11.7 |
HIP 92300 |
29.23 |
| 2026-06-09 12:00 |
18:46:40.64 |
-88:09:25.7 |
HIP 92300 |
29.01 |
| 2026-06-10 00:00 |
18:45:27.70 |
-88:09:39.2 |
HIP 92300 |
28.80 |
| 2026-06-10 12:00 |
18:44:14.22 |
-88:09:52.2 |
HIP 92300 |
28.61 |
| 2026-06-11 00:00 |
18:43:00.21 |
-88:10:04.8 |
HIP 92300 |
28.44 |
| 2026-06-11 12:00 |
18:41:45.69 |
-88:10:17.0 |
HIP 92300 |
28.29 |
| 2026-06-12 00:00 |
18:40:30.68 |
-88:10:28.6 |
HIP 92300 |
28.15 |
| 2026-06-12 12:00 |
18:39:15.18 |
-88:10:39.8 |
HIP 92300 |
28.03 |
| 2026-06-13 00:00 |
18:37:59.23 |
-88:10:50.5 |
HIP 92300 |
27.94 |
| 2026-06-13 12:00 |
18:36:42.84 |
-88:11:00.7 |
HIP 92300 |
27.86 |
| 2026-06-14 00:00 |
18:35:26.02 |
-88:11:10.5 |
HIP 92300 |
27.79 |
| 2026-06-14 12:00 |
18:34:08.81 |
-88:11:19.7 |
HIP 92300 |
27.75 |
| 2026-06-15 00:00 |
18:32:51.20 |
-88:11:28.5 |
HIP 92300 |
27.73 |
| 2026-06-15 12:00 |
18:31:33.23 |
-88:11:36.8 |
HIP 92300 |
27.72 |
| 2026-06-16 00:00 |
18:30:14.92 |
-88:11:44.5 |
HIP 92300 |
27.74 |
| 2026-06-16 12:00 |
18:28:56.28 |
-88:11:51.8 |
HIP 92300 |
27.77 |
| 2026-06-17 00:00 |
18:27:37.34 |
-88:11:58.6 |
HIP 92300 |
27.83 |
| 2026-06-17 12:00 |
18:26:18.11 |
-88:12:04.9 |
HIP 92300 |
27.90 |
| 2026-06-18 00:00 |
18:24:58.63 |
-88:12:10.6 |
HIP 92300 |
27.99 |
| 2026-06-18 12:00 |
18:23:38.91 |
-88:12:15.9 |
HIP 92300 |
28.10 |
| 2026-06-19 00:00 |
18:22:18.96 |
-88:12:20.7 |
HIP 92300 |
28.23 |
| 2026-06-19 12:00 |
18:20:58.83 |
-88:12:24.9 |
HIP 92300 |
28.38 |
| 2026-06-20 00:00 |
18:19:38.52 |
-88:12:28.6 |
HIP 92300 |
28.54 |
| 2026-06-20 12:00 |
18:18:18.06 |
-88:12:31.9 |
HIP 92300 |
28.72 |
| 2026-06-21 00:00 |
18:16:57.47 |
-88:12:34.6 |
HIP 92300 |
28.92 |
| 2026-06-21 12:00 |
18:15:36.77 |
-88:12:36.8 |
HIP 92300 |
29.14 |
| 2026-06-22 00:00 |
18:14:15.99 |
-88:12:38.5 |
HIP 92300 |
29.37 |