| Parameter |
Value |
| Designation |
C/1985 T1 (Thiele) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1985-12-19T05:04:22.480320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
133 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
13.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1985-12-16.0000000 |
| e |
0.98328249 |
| q (au) |
1.317141 |
| a (au) |
78.788093 |
| i (deg) |
139.069283 |
| Ω (om, deg) |
53.012812 |
| ω (w, deg) |
53.000230 |
| M (ma, deg) |
359.995474 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.369 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.369 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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) |
| 2026-07-29 00:00 |
12:32:43.73 |
-30:20:20.6 |
HIP 61232 |
17.71 |
| 2026-07-29 12:00 |
12:32:44.63 |
-30:20:13.7 |
HIP 61232 |
17.58 |
| 2026-07-30 00:00 |
12:32:45.54 |
-30:20:07.0 |
HIP 61232 |
17.46 |
| 2026-07-30 12:00 |
12:32:46.47 |
-30:20:00.3 |
HIP 61232 |
17.34 |
| 2026-07-31 00:00 |
12:32:47.41 |
-30:19:53.8 |
HIP 61232 |
17.22 |
| 2026-07-31 12:00 |
12:32:48.37 |
-30:19:47.4 |
HIP 61232 |
17.11 |
| 2026-08-01 00:00 |
12:32:49.34 |
-30:19:41.2 |
HIP 61232 |
17.00 |
| 2026-08-01 12:00 |
12:32:50.33 |
-30:19:35.1 |
HIP 61232 |
16.90 |
| 2026-08-02 00:00 |
12:32:51.33 |
-30:19:29.1 |
HIP 61232 |
16.80 |
| 2026-08-02 12:00 |
12:32:52.35 |
-30:19:23.3 |
HIP 61232 |
16.71 |
| 2026-08-03 00:00 |
12:32:53.38 |
-30:19:17.6 |
HIP 61232 |
16.62 |
| 2026-08-03 12:00 |
12:32:54.42 |
-30:19:12.0 |
HIP 61232 |
16.54 |
| 2026-08-04 00:00 |
12:32:55.48 |
-30:19:06.5 |
HIP 61232 |
16.47 |
| 2026-08-04 12:00 |
12:32:56.56 |
-30:19:01.2 |
HIP 61232 |
16.40 |
| 2026-08-05 00:00 |
12:32:57.65 |
-30:18:56.0 |
HIP 61232 |
16.33 |
| 2026-08-05 12:00 |
12:32:58.76 |
-30:18:51.0 |
HIP 61232 |
16.27 |
| 2026-08-06 00:00 |
12:32:59.87 |
-30:18:46.1 |
HIP 61232 |
16.22 |
| 2026-08-06 12:00 |
12:33:01.01 |
-30:18:41.3 |
HIP 61232 |
16.18 |
| 2026-08-07 00:00 |
12:33:02.16 |
-30:18:36.7 |
HIP 61232 |
16.14 |
| 2026-08-07 12:00 |
12:33:03.32 |
-30:18:32.2 |
HIP 61232 |
16.11 |
| 2026-08-08 00:00 |
12:33:04.49 |
-30:18:27.8 |
HIP 61232 |
16.08 |
| 2026-08-08 12:00 |
12:33:05.68 |
-30:18:23.6 |
HIP 61232 |
16.07 |
| 2026-08-09 00:00 |
12:33:06.89 |
-30:18:19.5 |
HIP 61232 |
16.06 |
| 2026-08-09 12:00 |
12:33:08.10 |
-30:18:15.6 |
HIP 61232 |
16.06 |
| 2026-08-10 00:00 |
12:33:09.34 |
-30:18:11.8 |
HIP 61232 |
16.06 |
| 2026-08-10 12:00 |
12:33:10.58 |
-30:18:08.1 |
HIP 61232 |
16.07 |
| 2026-08-11 00:00 |
12:33:11.84 |
-30:18:04.6 |
HIP 61232 |
16.09 |
| 2026-08-11 12:00 |
12:33:13.11 |
-30:18:01.2 |
HIP 61232 |
16.12 |
| 2026-08-12 00:00 |
12:33:14.40 |
-30:17:57.9 |
HIP 61232 |
16.16 |
| 2026-08-12 12:00 |
12:33:15.70 |
-30:17:54.8 |
HIP 61232 |
16.20 |
| 2026-08-13 00:00 |
12:33:17.01 |
-30:17:51.8 |
HIP 61232 |
16.26 |
| 2026-08-13 12:00 |
12:33:18.33 |
-30:17:49.0 |
HIP 61232 |
16.32 |
| 2026-08-14 00:00 |
12:33:19.67 |
-30:17:46.3 |
HIP 61232 |
16.39 |
| 2026-08-14 12:00 |
12:33:21.02 |
-30:17:43.7 |
HIP 61232 |
16.46 |
| 2026-08-15 00:00 |
12:33:22.38 |
-30:17:41.3 |
HIP 61232 |
16.55 |
| 2026-08-15 12:00 |
12:33:23.76 |
-30:17:39.1 |
HIP 61232 |
16.64 |
| 2026-08-16 00:00 |
12:33:25.15 |
-30:17:36.9 |
HIP 61232 |
16.74 |
| 2026-08-16 12:00 |
12:33:26.55 |
-30:17:34.9 |
HIP 61232 |
16.85 |
| 2026-08-17 00:00 |
12:33:27.96 |
-30:17:33.1 |
HIP 61232 |
16.97 |
| 2026-08-17 12:00 |
12:33:29.39 |
-30:17:31.4 |
HIP 61232 |
17.10 |
| 2026-08-18 00:00 |
12:33:30.82 |
-30:17:29.8 |
HIP 61232 |
17.23 |
| 2026-08-18 12:00 |
12:33:32.27 |
-30:17:28.4 |
HIP 61232 |
17.37 |
| 2026-08-19 00:00 |
12:33:33.73 |
-30:17:27.1 |
HIP 61232 |
17.52 |