| Parameter |
Value |
| Designation |
C/1997 T1 (Utsunomiya) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1997-12-10T03:28:30.063360Z |
| Orbit solution date (soln_date, UTC) |
2022-02-03T20:42:52Z |
| Obs used |
681 |
| NEO |
- |
| M1 |
7.900 |
| K1 |
18.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1997-11-20.0000000 |
| e |
0.99851974 |
| q (au) |
1.359109 |
| a (au) |
918.157376 |
| i (deg) |
127.992638 |
| Ω (om, deg) |
53.702748 |
| ω (w, deg) |
95.965142 |
| M (ma, deg) |
359.999286 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.692 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.692 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
09:24:52.95 |
-38:52:22.1 |
HIP 46129 |
6.12 |
| 2026-06-01 12:00 |
09:24:53.88 |
-38:51:58.1 |
HIP 46129 |
6.11 |
| 2026-06-02 00:00 |
09:24:54.83 |
-38:51:34.2 |
HIP 46129 |
6.13 |
| 2026-06-02 12:00 |
09:24:55.80 |
-38:51:10.5 |
HIP 46129 |
6.18 |
| 2026-06-03 00:00 |
09:24:56.79 |
-38:50:46.9 |
HIP 46129 |
6.27 |
| 2026-06-03 12:00 |
09:24:57.80 |
-38:50:23.5 |
HIP 46129 |
6.39 |
| 2026-06-04 00:00 |
09:24:58.84 |
-38:50:00.2 |
HIP 46129 |
6.55 |
| 2026-06-04 12:00 |
09:24:59.89 |
-38:49:37.1 |
HIP 46129 |
6.73 |
| 2026-06-05 00:00 |
09:25:00.97 |
-38:49:14.1 |
HIP 46129 |
6.94 |
| 2026-06-05 12:00 |
09:25:02.07 |
-38:48:51.3 |
HIP 46129 |
7.18 |
| 2026-06-06 00:00 |
09:25:03.18 |
-38:48:28.6 |
HIP 46129 |
7.44 |
| 2026-06-06 12:00 |
09:25:04.32 |
-38:48:06.1 |
HIP 46129 |
7.71 |
| 2026-06-07 00:00 |
09:25:05.48 |
-38:47:43.7 |
HIP 46129 |
8.01 |
| 2026-06-07 12:00 |
09:25:06.66 |
-38:47:21.5 |
HIP 46129 |
8.32 |
| 2026-06-08 00:00 |
09:25:07.86 |
-38:46:59.5 |
HIP 46129 |
8.64 |
| 2026-06-08 12:00 |
09:25:09.09 |
-38:46:37.6 |
HIP 46129 |
8.98 |
| 2026-06-09 00:00 |
09:25:10.33 |
-38:46:15.9 |
HIP 46129 |
9.33 |
| 2026-06-09 12:00 |
09:25:11.59 |
-38:45:54.3 |
HIP 46129 |
9.68 |
| 2026-06-10 00:00 |
09:25:12.87 |
-38:45:33.0 |
HIP 46129 |
10.05 |
| 2026-06-10 12:00 |
09:25:14.17 |
-38:45:11.7 |
HIP 46129 |
10.42 |
| 2026-06-11 00:00 |
09:25:15.49 |
-38:44:50.7 |
HIP 46129 |
10.80 |
| 2026-06-11 12:00 |
09:25:16.84 |
-38:44:29.8 |
HIP 46129 |
11.19 |
| 2026-06-12 00:00 |
09:25:18.20 |
-38:44:09.1 |
HIP 46129 |
11.58 |
| 2026-06-12 12:00 |
09:25:19.58 |
-38:43:48.6 |
HIP 46129 |
11.98 |
| 2026-06-13 00:00 |
09:25:20.98 |
-38:43:28.2 |
HIP 46129 |
12.38 |
| 2026-06-13 12:00 |
09:25:22.40 |
-38:43:08.1 |
HIP 46129 |
12.79 |
| 2026-06-14 00:00 |
09:25:23.84 |
-38:42:48.1 |
HIP 46129 |
13.20 |
| 2026-06-14 12:00 |
09:25:25.30 |
-38:42:28.2 |
HIP 46129 |
13.61 |
| 2026-06-15 00:00 |
09:25:26.77 |
-38:42:08.6 |
HIP 46129 |
14.03 |
| 2026-06-15 12:00 |
09:25:28.27 |
-38:41:49.2 |
HIP 46129 |
14.45 |
| 2026-06-16 00:00 |
09:25:29.79 |
-38:41:29.9 |
HIP 46129 |
14.87 |
| 2026-06-16 12:00 |
09:25:31.32 |
-38:41:10.8 |
HIP 46129 |
15.29 |
| 2026-06-17 00:00 |
09:25:32.87 |
-38:40:51.9 |
HIP 46129 |
15.72 |
| 2026-06-17 12:00 |
09:25:34.44 |
-38:40:33.2 |
HIP 46129 |
16.14 |
| 2026-06-18 00:00 |
09:25:36.03 |
-38:40:14.7 |
HIP 46129 |
16.57 |
| 2026-06-18 12:00 |
09:25:37.64 |
-38:39:56.3 |
HIP 46129 |
17.00 |
| 2026-06-19 00:00 |
09:25:39.26 |
-38:39:38.2 |
HIP 46129 |
17.44 |
| 2026-06-19 12:00 |
09:25:40.91 |
-38:39:20.2 |
HIP 46129 |
17.87 |
| 2026-06-20 00:00 |
09:25:42.57 |
-38:39:02.5 |
HIP 46129 |
18.30 |
| 2026-06-20 12:00 |
09:25:44.24 |
-38:38:44.9 |
HIP 46129 |
18.74 |
| 2026-06-21 00:00 |
09:25:45.94 |
-38:38:27.6 |
HIP 46129 |
19.18 |
| 2026-06-21 12:00 |
09:25:47.65 |
-38:38:10.4 |
HIP 46129 |
19.62 |
| 2026-06-22 00:00 |
09:25:49.38 |
-38:37:53.4 |
HIP 46129 |
20.05 |