| 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) |
| 2026-05-12 00:00 |
12:33:51.34 |
-30:56:46.8 |
HIP 61209 |
26.51 |
| 2026-05-12 12:00 |
12:33:49.66 |
-30:56:29.9 |
HIP 61209 |
26.51 |
| 2026-05-13 00:00 |
12:33:47.99 |
-30:56:12.9 |
HIP 61209 |
26.51 |
| 2026-05-13 12:00 |
12:33:46.34 |
-30:55:56.0 |
HIP 61209 |
26.53 |
| 2026-05-14 00:00 |
12:33:44.69 |
-30:55:39.0 |
HIP 61209 |
26.56 |
| 2026-05-14 12:00 |
12:33:43.07 |
-30:55:22.0 |
HIP 61209 |
26.60 |
| 2026-05-15 00:00 |
12:33:41.45 |
-30:55:05.0 |
HIP 61209 |
26.64 |
| 2026-05-15 12:00 |
12:33:39.85 |
-30:54:47.9 |
HIP 61133 |
26.35 |
| 2026-05-16 00:00 |
12:33:38.26 |
-30:54:30.8 |
HIP 61133 |
26.06 |
| 2026-05-16 12:00 |
12:33:36.69 |
-30:54:13.8 |
HIP 61133 |
25.78 |
| 2026-05-17 00:00 |
12:33:35.13 |
-30:53:56.7 |
HIP 61133 |
25.50 |
| 2026-05-17 12:00 |
12:33:33.58 |
-30:53:39.5 |
HIP 61133 |
25.24 |
| 2026-05-18 00:00 |
12:33:32.05 |
-30:53:22.4 |
HIP 61133 |
24.98 |
| 2026-05-18 12:00 |
12:33:30.53 |
-30:53:05.3 |
HIP 61133 |
24.73 |
| 2026-05-19 00:00 |
12:33:29.02 |
-30:52:48.1 |
HIP 61133 |
24.48 |
| 2026-05-19 12:00 |
12:33:27.53 |
-30:52:31.0 |
HIP 61133 |
24.25 |
| 2026-05-20 00:00 |
12:33:26.06 |
-30:52:13.8 |
HIP 61133 |
24.02 |
| 2026-05-20 12:00 |
12:33:24.60 |
-30:51:56.7 |
HIP 61133 |
23.80 |
| 2026-05-21 00:00 |
12:33:23.15 |
-30:51:39.5 |
HIP 61133 |
23.59 |
| 2026-05-21 12:00 |
12:33:21.72 |
-30:51:22.4 |
HIP 61133 |
23.39 |
| 2026-05-22 00:00 |
12:33:20.30 |
-30:51:05.2 |
HIP 61133 |
23.20 |
| 2026-05-22 12:00 |
12:33:18.90 |
-30:50:48.0 |
HIP 61133 |
23.02 |
| 2026-05-23 00:00 |
12:33:17.51 |
-30:50:30.9 |
HIP 61133 |
22.84 |
| 2026-05-23 12:00 |
12:33:16.13 |
-30:50:13.7 |
HIP 61133 |
22.68 |
| 2026-05-24 00:00 |
12:33:14.78 |
-30:49:56.5 |
HIP 61133 |
22.52 |
| 2026-05-24 12:00 |
12:33:13.43 |
-30:49:39.4 |
HIP 61133 |
22.38 |
| 2026-05-25 00:00 |
12:33:12.10 |
-30:49:22.2 |
HIP 61133 |
22.24 |
| 2026-05-25 12:00 |
12:33:10.79 |
-30:49:05.1 |
HIP 61133 |
22.11 |
| 2026-05-26 00:00 |
12:33:09.49 |
-30:48:48.0 |
HIP 61133 |
21.99 |
| 2026-05-26 12:00 |
12:33:08.21 |
-30:48:30.9 |
HIP 61133 |
21.88 |
| 2026-05-27 00:00 |
12:33:06.94 |
-30:48:13.8 |
HIP 61133 |
21.78 |
| 2026-05-27 12:00 |
12:33:05.69 |
-30:47:56.7 |
HIP 61133 |
21.69 |
| 2026-05-28 00:00 |
12:33:04.46 |
-30:47:39.6 |
HIP 61133 |
21.61 |
| 2026-05-28 12:00 |
12:33:03.24 |
-30:47:22.5 |
HIP 61133 |
21.54 |
| 2026-05-29 00:00 |
12:33:02.03 |
-30:47:05.5 |
HIP 61133 |
21.48 |
| 2026-05-29 12:00 |
12:33:00.84 |
-30:46:48.5 |
HIP 61133 |
21.42 |
| 2026-05-30 00:00 |
12:32:59.67 |
-30:46:31.5 |
HIP 61133 |
21.38 |
| 2026-05-30 12:00 |
12:32:58.51 |
-30:46:14.5 |
HIP 61133 |
21.34 |
| 2026-05-31 00:00 |
12:32:57.37 |
-30:45:57.5 |
HIP 61133 |
21.32 |
| 2026-05-31 12:00 |
12:32:56.25 |
-30:45:40.6 |
HIP 61133 |
21.30 |
| 2026-06-01 00:00 |
12:32:55.14 |
-30:45:23.7 |
HIP 61133 |
21.29 |
| 2026-06-01 12:00 |
12:32:54.05 |
-30:45:06.8 |
HIP 61133 |
21.30 |
| 2026-06-02 00:00 |
12:32:52.97 |
-30:44:49.9 |
HIP 61133 |
21.30 |