C/1997 T1 (Utsunomiya)
| 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) |
| 2026-02-03 00:00 |
09:31:07.94 |
-40:21:06.7 |
HIP 46723 |
5.97 |
| 2026-02-03 12:00 |
09:31:04.87 |
-40:21:03.3 |
HIP 46723 |
6.32 |
| 2026-02-04 00:00 |
09:31:01.79 |
-40:20:59.7 |
HIP 46723 |
6.70 |
| 2026-02-04 12:00 |
09:30:58.71 |
-40:20:55.7 |
HIP 46723 |
7.11 |
| 2026-02-05 00:00 |
09:30:55.63 |
-40:20:51.6 |
HIP 46612 |
7.31 |
| 2026-02-05 12:00 |
09:30:52.55 |
-40:20:47.1 |
HIP 46612 |
6.72 |
| 2026-02-06 00:00 |
09:30:49.46 |
-40:20:42.4 |
HIP 46612 |
6.14 |
| 2026-02-06 12:00 |
09:30:46.37 |
-40:20:37.4 |
HIP 46612 |
5.55 |
| 2026-02-07 00:00 |
09:30:43.29 |
-40:20:32.2 |
HIP 46612 |
4.96 |
| 2026-02-07 12:00 |
09:30:40.20 |
-40:20:26.6 |
HIP 46612 |
4.38 |
| 2026-02-08 00:00 |
09:30:37.10 |
-40:20:20.9 |
HIP 46612 |
3.80 |
| 2026-02-08 12:00 |
09:30:34.01 |
-40:20:14.8 |
HIP 46612 |
3.23 |
| 2026-02-09 00:00 |
09:30:30.92 |
-40:20:08.5 |
HIP 46612 |
2.67 |
| 2026-02-09 12:00 |
09:30:27.83 |
-40:20:01.9 |
HIP 46612 |
2.14 |
| 2026-02-10 00:00 |
09:30:24.73 |
-40:19:55.1 |
HIP 46612 |
1.65 |
| 2026-02-10 12:00 |
09:30:21.64 |
-40:19:48.0 |
HIP 46612 |
1.27 |
| 2026-02-11 00:00 |
09:30:18.55 |
-40:19:40.7 |
HIP 46612 |
1.10 |
| 2026-02-11 12:00 |
09:30:15.46 |
-40:19:33.0 |
HIP 46612 |
1.25 |
| 2026-02-12 00:00 |
09:30:12.37 |
-40:19:25.1 |
HIP 46612 |
1.63 |
| 2026-02-12 12:00 |
09:30:09.28 |
-40:19:17.0 |
HIP 46612 |
2.12 |
| 2026-02-13 00:00 |
09:30:06.19 |
-40:19:08.6 |
HIP 46612 |
2.65 |
| 2026-02-13 12:00 |
09:30:03.11 |
-40:19:00.0 |
HIP 46612 |
3.22 |
| 2026-02-14 00:00 |
09:30:00.03 |
-40:18:51.0 |
HIP 46612 |
3.80 |
| 2026-02-14 12:00 |
09:29:56.95 |
-40:18:41.8 |
HIP 46612 |
4.38 |
| 2026-02-15 00:00 |
09:29:53.87 |
-40:18:32.4 |
HIP 46612 |
4.98 |
| 2026-02-15 12:00 |
09:29:50.79 |
-40:18:22.7 |
HIP 46612 |
5.58 |
| 2026-02-16 00:00 |
09:29:47.72 |
-40:18:12.7 |
HIP 46612 |
6.18 |
| 2026-02-16 12:00 |
09:29:44.65 |
-40:18:02.5 |
HIP 46612 |
6.78 |
| 2026-02-17 00:00 |
09:29:41.59 |
-40:17:52.1 |
HIP 46612 |
7.39 |
| 2026-02-17 12:00 |
09:29:38.52 |
-40:17:41.3 |
HIP 46612 |
7.99 |
| 2026-02-18 00:00 |
09:29:35.47 |
-40:17:30.4 |
HIP 46612 |
8.60 |
| 2026-02-18 12:00 |
09:29:32.41 |
-40:17:19.2 |
HIP 46612 |
9.21 |
| 2026-02-19 00:00 |
09:29:29.37 |
-40:17:07.7 |
HIP 46612 |
9.82 |
| 2026-02-19 12:00 |
09:29:26.32 |
-40:16:56.0 |
HIP 46612 |
10.43 |
| 2026-02-20 00:00 |
09:29:23.29 |
-40:16:44.0 |
HIP 46612 |
11.05 |
| 2026-02-20 12:00 |
09:29:20.25 |
-40:16:31.8 |
HIP 46612 |
11.66 |
| 2026-02-21 00:00 |
09:29:17.23 |
-40:16:19.3 |
HIP 46612 |
12.27 |
| 2026-02-21 12:00 |
09:29:14.20 |
-40:16:06.6 |
HIP 46612 |
12.89 |
| 2026-02-22 00:00 |
09:29:11.19 |
-40:15:53.7 |
HIP 46455 |
13.01 |
| 2026-02-22 12:00 |
09:29:08.18 |
-40:15:40.5 |
HIP 46455 |
12.48 |
| 2026-02-23 00:00 |
09:29:05.18 |
-40:15:27.0 |
HIP 46455 |
11.96 |
| 2026-02-23 12:00 |
09:29:02.18 |
-40:15:13.4 |
HIP 46455 |
11.44 |
| 2026-02-24 00:00 |
09:28:59.20 |
-40:14:59.5 |
HIP 46455 |
10.93 |