C/2002 F1 (Utsunomiya)
| 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) |
| 2026-02-03 00:00 |
18:57:48.30 |
-86:13:05.1 |
HIP 92332 |
8.74 |
| 2026-02-03 12:00 |
18:58:22.27 |
-86:13:20.5 |
HIP 92332 |
9.33 |
| 2026-02-04 00:00 |
18:58:56.14 |
-86:13:36.1 |
HIP 92332 |
9.92 |
| 2026-02-04 12:00 |
18:59:29.91 |
-86:13:51.9 |
HIP 92332 |
10.51 |
| 2026-02-05 00:00 |
19:00:03.59 |
-86:14:07.9 |
HIP 92332 |
11.11 |
| 2026-02-05 12:00 |
19:00:37.16 |
-86:14:24.1 |
HIP 92332 |
11.70 |
| 2026-02-06 00:00 |
19:01:10.64 |
-86:14:40.4 |
HIP 92332 |
12.29 |
| 2026-02-06 12:00 |
19:01:44.01 |
-86:14:57.0 |
HIP 92332 |
12.89 |
| 2026-02-07 00:00 |
19:02:17.27 |
-86:15:13.7 |
HIP 92332 |
13.48 |
| 2026-02-07 12:00 |
19:02:50.44 |
-86:15:30.6 |
HIP 92332 |
14.07 |
| 2026-02-08 00:00 |
19:03:23.50 |
-86:15:47.7 |
HIP 92332 |
14.66 |
| 2026-02-08 12:00 |
19:03:56.44 |
-86:16:05.0 |
HIP 92332 |
15.26 |
| 2026-02-09 00:00 |
19:04:29.29 |
-86:16:22.5 |
HIP 92332 |
15.85 |
| 2026-02-09 12:00 |
19:05:02.02 |
-86:16:40.1 |
HIP 94002 |
16.17 |
| 2026-02-10 00:00 |
19:05:34.63 |
-86:16:58.0 |
HIP 94002 |
16.35 |
| 2026-02-10 12:00 |
19:06:07.14 |
-86:17:16.0 |
HIP 94002 |
16.57 |
| 2026-02-11 00:00 |
19:06:39.53 |
-86:17:34.2 |
HIP 94002 |
16.81 |
| 2026-02-11 12:00 |
19:07:11.80 |
-86:17:52.6 |
HIP 94002 |
17.07 |
| 2026-02-12 00:00 |
19:07:43.96 |
-86:18:11.2 |
HIP 94002 |
17.35 |
| 2026-02-12 12:00 |
19:08:16.00 |
-86:18:29.9 |
HIP 94002 |
17.65 |
| 2026-02-13 00:00 |
19:08:47.91 |
-86:18:48.8 |
HIP 94002 |
17.97 |
| 2026-02-13 12:00 |
19:09:19.71 |
-86:19:08.0 |
HIP 94002 |
18.31 |
| 2026-02-14 00:00 |
19:09:51.38 |
-86:19:27.3 |
HIP 94002 |
18.67 |
| 2026-02-14 12:00 |
19:10:22.92 |
-86:19:46.8 |
HIP 94002 |
19.04 |
| 2026-02-15 00:00 |
19:10:54.34 |
-86:20:06.4 |
HIP 94002 |
19.43 |
| 2026-02-15 12:00 |
19:11:25.63 |
-86:20:26.3 |
HIP 94002 |
19.83 |
| 2026-02-16 00:00 |
19:11:56.78 |
-86:20:46.3 |
HIP 94002 |
20.25 |
| 2026-02-16 12:00 |
19:12:27.81 |
-86:21:06.5 |
HIP 94002 |
20.67 |
| 2026-02-17 00:00 |
19:12:58.70 |
-86:21:26.9 |
HIP 94002 |
21.11 |
| 2026-02-17 12:00 |
19:13:29.46 |
-86:21:47.5 |
HIP 94002 |
21.56 |
| 2026-02-18 00:00 |
19:14:00.07 |
-86:22:08.2 |
HIP 94002 |
22.02 |
| 2026-02-18 12:00 |
19:14:30.55 |
-86:22:29.1 |
HIP 94002 |
22.49 |
| 2026-02-19 00:00 |
19:15:00.89 |
-86:22:50.3 |
HIP 94002 |
22.97 |
| 2026-02-19 12:00 |
19:15:31.09 |
-86:23:11.5 |
HIP 94002 |
23.45 |
| 2026-02-20 00:00 |
19:16:01.14 |
-86:23:33.0 |
HIP 94002 |
23.95 |
| 2026-02-20 12:00 |
19:16:31.05 |
-86:23:54.6 |
HIP 94002 |
24.45 |
| 2026-02-21 00:00 |
19:17:00.81 |
-86:24:16.4 |
HIP 94002 |
24.95 |
| 2026-02-21 12:00 |
19:17:30.42 |
-86:24:38.4 |
HIP 94002 |
25.46 |
| 2026-02-22 00:00 |
19:17:59.88 |
-86:25:00.5 |
HIP 94002 |
25.98 |
| 2026-02-22 12:00 |
19:18:29.18 |
-86:25:22.9 |
HIP 94002 |
26.50 |
| 2026-02-23 00:00 |
19:18:58.34 |
-86:25:45.4 |
HIP 94002 |
27.03 |
| 2026-02-23 12:00 |
19:19:27.34 |
-86:26:08.0 |
HIP 94002 |
27.56 |
| 2026-02-24 00:00 |
19:19:56.18 |
-86:26:30.9 |
HIP 94002 |
28.10 |