| Parameter |
Value |
| Designation |
C/1979 S1 (Meier) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1979-10-17T08:06:07.672320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
45 |
| NEO |
- |
| M1 |
4.800 |
| K1 |
46.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1979-11-02.0000000 |
| e |
0.97299836 |
| q (au) |
1.431958 |
| a (au) |
53.032267 |
| i (deg) |
67.079393 |
| Ω (om, deg) |
297.631300 |
| ω (w, deg) |
112.564818 |
| M (ma, deg) |
0.039972 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.190 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.190 |
| 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) |
| 2026-09-20 00:00 |
11:25:13.35 |
-74:27:07.3 |
HIP 55902 |
16.41 |
| 2026-09-20 12:00 |
11:25:20.08 |
-74:27:13.8 |
HIP 55902 |
16.25 |
| 2026-09-21 00:00 |
11:25:26.81 |
-74:27:20.5 |
HIP 55902 |
16.10 |
| 2026-09-21 12:00 |
11:25:33.53 |
-74:27:27.5 |
HIP 55902 |
15.96 |
| 2026-09-22 00:00 |
11:25:40.24 |
-74:27:34.7 |
HIP 55902 |
15.85 |
| 2026-09-22 12:00 |
11:25:46.95 |
-74:27:42.1 |
HIP 55902 |
15.75 |
| 2026-09-23 00:00 |
11:25:53.65 |
-74:27:49.7 |
HIP 55902 |
15.67 |
| 2026-09-23 12:00 |
11:26:00.34 |
-74:27:57.6 |
HIP 55902 |
15.60 |
| 2026-09-24 00:00 |
11:26:07.02 |
-74:28:05.7 |
HIP 55902 |
15.55 |
| 2026-09-24 12:00 |
11:26:13.69 |
-74:28:14.0 |
HIP 55902 |
15.53 |
| 2026-09-25 00:00 |
11:26:20.36 |
-74:28:22.5 |
HIP 55902 |
15.51 |
| 2026-09-25 12:00 |
11:26:27.01 |
-74:28:31.2 |
HIP 55902 |
15.52 |
| 2026-09-26 00:00 |
11:26:33.65 |
-74:28:40.2 |
HIP 55902 |
15.55 |
| 2026-09-26 12:00 |
11:26:40.29 |
-74:28:49.4 |
HIP 55902 |
15.59 |
| 2026-09-27 00:00 |
11:26:46.91 |
-74:28:58.8 |
HIP 55902 |
15.65 |
| 2026-09-27 12:00 |
11:26:53.52 |
-74:29:08.4 |
HIP 55902 |
15.73 |
| 2026-09-28 00:00 |
11:27:00.13 |
-74:29:18.2 |
HIP 56144 |
15.65 |
| 2026-09-28 12:00 |
11:27:06.72 |
-74:29:28.3 |
HIP 56144 |
15.18 |
| 2026-09-29 00:00 |
11:27:13.29 |
-74:29:38.6 |
HIP 56144 |
14.71 |
| 2026-09-29 12:00 |
11:27:19.86 |
-74:29:49.1 |
HIP 56144 |
14.24 |
| 2026-09-30 00:00 |
11:27:26.41 |
-74:29:59.8 |
HIP 56144 |
13.77 |
| 2026-09-30 12:00 |
11:27:32.95 |
-74:30:10.7 |
HIP 56144 |
13.30 |
| 2026-10-01 00:00 |
11:27:39.47 |
-74:30:21.8 |
HIP 56144 |
12.83 |
| 2026-10-01 12:00 |
11:27:45.99 |
-74:30:33.2 |
HIP 56144 |
12.36 |
| 2026-10-02 00:00 |
11:27:52.48 |
-74:30:44.8 |
HIP 56144 |
11.88 |
| 2026-10-02 12:00 |
11:27:58.97 |
-74:30:56.6 |
HIP 56144 |
11.41 |
| 2026-10-03 00:00 |
11:28:05.43 |
-74:31:08.6 |
HIP 56144 |
10.94 |
| 2026-10-03 12:00 |
11:28:11.88 |
-74:31:20.8 |
HIP 56144 |
10.46 |
| 2026-10-04 00:00 |
11:28:18.32 |
-74:31:33.2 |
HIP 56144 |
9.99 |
| 2026-10-04 12:00 |
11:28:24.74 |
-74:31:45.8 |
HIP 56144 |
9.51 |
| 2026-10-05 00:00 |
11:28:31.14 |
-74:31:58.7 |
HIP 56144 |
9.03 |
| 2026-10-05 12:00 |
11:28:37.53 |
-74:32:11.7 |
HIP 56144 |
8.56 |
| 2026-10-06 00:00 |
11:28:43.90 |
-74:32:25.0 |
HIP 56144 |
8.08 |
| 2026-10-06 12:00 |
11:28:50.25 |
-74:32:38.5 |
HIP 56144 |
7.60 |
| 2026-10-07 00:00 |
11:28:56.58 |
-74:32:52.2 |
HIP 56144 |
7.12 |
| 2026-10-07 12:00 |
11:29:02.89 |
-74:33:06.1 |
HIP 56144 |
6.64 |
| 2026-10-08 00:00 |
11:29:09.18 |
-74:33:20.2 |
HIP 56144 |
6.16 |
| 2026-10-08 12:00 |
11:29:15.46 |
-74:33:34.5 |
HIP 56144 |
5.68 |
| 2026-10-09 00:00 |
11:29:21.71 |
-74:33:49.0 |
HIP 56144 |
5.20 |
| 2026-10-09 12:00 |
11:29:27.94 |
-74:34:03.7 |
HIP 56144 |
4.72 |
| 2026-10-10 00:00 |
11:29:34.15 |
-74:34:18.6 |
HIP 56144 |
4.24 |
| 2026-10-10 12:00 |
11:29:40.34 |
-74:34:33.8 |
HIP 56144 |
3.75 |
| 2026-10-11 00:00 |
11:29:46.51 |
-74:34:49.1 |
HIP 56144 |
3.27 |