| Parameter |
Value |
| Designation |
C/2000 W1 (Utsunomiya-Jones) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2000-12-26T13:25:20.971200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:08Z |
| Obs used |
440 |
| NEO |
- |
| M1 |
12.600 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2000-12-11.0000000 |
| e |
1.00000177 |
| q (au) |
0.321181 |
| a (au) |
-181492.894591 |
| i (deg) |
160.165435 |
| Ω (om, deg) |
10.765960 |
| ω (w, deg) |
51.508868 |
| M (ma, deg) |
-0.000000 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.558 + 3.641\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.558 |
| n |
3.641 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.978 |
| δ90 |
1.000 |
| 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 |
| 2000-11-18 |
2000-11-30 |
-31.0615 |
-1.440 |
| 2000-11-30 |
2000-12-24 |
+5.5320 |
+1.050 |
| 2000-12-28 |
2001-04-26 |
-1.8686 |
+0.093 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
09:48:03.32 |
-00:56:39.1 |
HIP 48026 |
10.87 |
| 2026-03-26 12:00 |
09:48:01.46 |
-00:56:23.7 |
HIP 48026 |
10.54 |
| 2026-03-27 00:00 |
09:47:59.60 |
-00:56:08.3 |
HIP 48026 |
10.24 |
| 2026-03-27 12:00 |
09:47:57.76 |
-00:55:52.9 |
HIP 48026 |
9.95 |
| 2026-03-28 00:00 |
09:47:55.94 |
-00:55:37.5 |
HIP 48026 |
9.69 |
| 2026-03-28 12:00 |
09:47:54.13 |
-00:55:22.2 |
HIP 48026 |
9.45 |
| 2026-03-29 00:00 |
09:47:52.33 |
-00:55:06.9 |
HIP 48026 |
9.24 |
| 2026-03-29 12:00 |
09:47:50.55 |
-00:54:51.5 |
HIP 48026 |
9.06 |
| 2026-03-30 00:00 |
09:47:48.78 |
-00:54:36.3 |
HIP 48026 |
8.91 |
| 2026-03-30 12:00 |
09:47:47.03 |
-00:54:21.0 |
HIP 48026 |
8.78 |
| 2026-03-31 00:00 |
09:47:45.29 |
-00:54:05.7 |
HIP 48026 |
8.69 |
| 2026-03-31 12:00 |
09:47:43.57 |
-00:53:50.5 |
HIP 48026 |
8.62 |
| 2026-04-01 00:00 |
09:47:41.86 |
-00:53:35.3 |
HIP 48026 |
8.59 |
| 2026-04-01 12:00 |
09:47:40.17 |
-00:53:20.1 |
HIP 48026 |
8.58 |
| 2026-04-02 00:00 |
09:47:38.49 |
-00:53:05.0 |
HIP 48026 |
8.61 |
| 2026-04-02 12:00 |
09:47:36.83 |
-00:52:49.9 |
HIP 48026 |
8.66 |
| 2026-04-03 00:00 |
09:47:35.18 |
-00:52:34.8 |
HIP 48026 |
8.74 |
| 2026-04-03 12:00 |
09:47:33.55 |
-00:52:19.7 |
HIP 48026 |
8.85 |
| 2026-04-04 00:00 |
09:47:31.93 |
-00:52:04.7 |
HIP 48026 |
8.98 |
| 2026-04-04 12:00 |
09:47:30.34 |
-00:51:49.7 |
HIP 48026 |
9.14 |
| 2026-04-05 00:00 |
09:47:28.75 |
-00:51:34.7 |
HIP 48026 |
9.31 |
| 2026-04-05 12:00 |
09:47:27.19 |
-00:51:19.8 |
HIP 48026 |
9.51 |
| 2026-04-06 00:00 |
09:47:25.63 |
-00:51:04.9 |
HIP 48026 |
9.72 |
| 2026-04-06 12:00 |
09:47:24.10 |
-00:50:50.0 |
HIP 48026 |
9.96 |
| 2026-04-07 00:00 |
09:47:22.58 |
-00:50:35.2 |
HIP 48026 |
10.20 |
| 2026-04-07 12:00 |
09:47:21.08 |
-00:50:20.4 |
HIP 48026 |
10.46 |
| 2026-04-08 00:00 |
09:47:19.60 |
-00:50:05.7 |
HIP 48026 |
10.73 |
| 2026-04-08 12:00 |
09:47:18.13 |
-00:49:50.9 |
HIP 48026 |
11.01 |
| 2026-04-09 00:00 |
09:47:16.67 |
-00:49:36.3 |
HIP 48026 |
11.30 |
| 2026-04-09 12:00 |
09:47:15.24 |
-00:49:21.7 |
HIP 48026 |
11.59 |
| 2026-04-10 00:00 |
09:47:13.82 |
-00:49:07.1 |
HIP 48026 |
11.90 |
| 2026-04-10 12:00 |
09:47:12.42 |
-00:48:52.5 |
HIP 48000 |
11.91 |
| 2026-04-11 00:00 |
09:47:11.04 |
-00:48:38.0 |
HIP 48000 |
11.62 |
| 2026-04-11 12:00 |
09:47:09.67 |
-00:48:23.6 |
HIP 48000 |
11.34 |
| 2026-04-12 00:00 |
09:47:08.32 |
-00:48:09.2 |
HIP 48000 |
11.07 |
| 2026-04-12 12:00 |
09:47:06.99 |
-00:47:54.9 |
HIP 48000 |
10.81 |
| 2026-04-13 00:00 |
09:47:05.68 |
-00:47:40.6 |
HIP 48000 |
10.56 |
| 2026-04-13 12:00 |
09:47:04.38 |
-00:47:26.3 |
HIP 48000 |
10.32 |
| 2026-04-14 00:00 |
09:47:03.10 |
-00:47:12.1 |
HIP 48000 |
10.10 |
| 2026-04-14 12:00 |
09:47:01.84 |
-00:46:58.0 |
HIP 48000 |
9.88 |
| 2026-04-15 00:00 |
09:47:00.60 |
-00:46:43.9 |
HIP 48000 |
9.67 |
| 2026-04-15 12:00 |
09:46:59.37 |
-00:46:29.9 |
HIP 48000 |
9.48 |
| 2026-04-16 00:00 |
09:46:58.17 |
-00:46:15.9 |
HIP 48000 |
9.30 |