C/1984 S1 (Meier)
| Parameter |
Value |
| Designation |
C/1984 S1 (Meier) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1984-10-13T23:45:57.159360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
12 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1984-09-23.0000000 |
| e |
0.99898032 |
| q (au) |
0.856608 |
| a (au) |
840.076952 |
| i (deg) |
145.614483 |
| Ω (om, deg) |
11.711482 |
| ω (w, deg) |
128.076601 |
| M (ma, deg) |
359.999150 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.608 + 3.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.608 |
| n |
3.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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 |
04:54:47.71 |
-08:33:53.0 |
HIP 22693 |
30.49 |
| 2026-02-03 12:00 |
04:54:46.71 |
-08:33:42.1 |
HIP 22693 |
30.28 |
| 2026-02-04 00:00 |
04:54:45.73 |
-08:33:31.1 |
HIP 22693 |
30.08 |
| 2026-02-04 12:00 |
04:54:44.76 |
-08:33:20.0 |
HIP 22693 |
29.88 |
| 2026-02-05 00:00 |
04:54:43.81 |
-08:33:08.9 |
HIP 22693 |
29.69 |
| 2026-02-05 12:00 |
04:54:42.87 |
-08:32:57.7 |
HIP 22693 |
29.50 |
| 2026-02-06 00:00 |
04:54:41.95 |
-08:32:46.4 |
HIP 22693 |
29.32 |
| 2026-02-06 12:00 |
04:54:41.04 |
-08:32:35.0 |
HIP 22693 |
29.14 |
| 2026-02-07 00:00 |
04:54:40.14 |
-08:32:23.5 |
HIP 22693 |
28.97 |
| 2026-02-07 12:00 |
04:54:39.26 |
-08:32:12.0 |
HIP 22693 |
28.81 |
| 2026-02-08 00:00 |
04:54:38.40 |
-08:32:00.4 |
HIP 22693 |
28.65 |
| 2026-02-08 12:00 |
04:54:37.55 |
-08:31:48.7 |
HIP 22693 |
28.50 |
| 2026-02-09 00:00 |
04:54:36.71 |
-08:31:37.0 |
HIP 22693 |
28.35 |
| 2026-02-09 12:00 |
04:54:35.89 |
-08:31:25.1 |
HIP 22693 |
28.21 |
| 2026-02-10 00:00 |
04:54:35.08 |
-08:31:13.3 |
HIP 22693 |
28.08 |
| 2026-02-10 12:00 |
04:54:34.29 |
-08:31:01.3 |
HIP 22693 |
27.95 |
| 2026-02-11 00:00 |
04:54:33.51 |
-08:30:49.3 |
HIP 22693 |
27.83 |
| 2026-02-11 12:00 |
04:54:32.75 |
-08:30:37.2 |
HIP 22693 |
27.71 |
| 2026-02-12 00:00 |
04:54:32.00 |
-08:30:25.0 |
HIP 22693 |
27.60 |
| 2026-02-12 12:00 |
04:54:31.27 |
-08:30:12.8 |
HIP 22693 |
27.49 |
| 2026-02-13 00:00 |
04:54:30.55 |
-08:30:00.5 |
HIP 22693 |
27.40 |
| 2026-02-13 12:00 |
04:54:29.85 |
-08:29:48.1 |
HIP 22693 |
27.31 |
| 2026-02-14 00:00 |
04:54:29.16 |
-08:29:35.7 |
HIP 22693 |
27.22 |
| 2026-02-14 12:00 |
04:54:28.49 |
-08:29:23.2 |
HIP 22693 |
27.14 |
| 2026-02-15 00:00 |
04:54:27.84 |
-08:29:10.7 |
HIP 22693 |
27.07 |
| 2026-02-15 12:00 |
04:54:27.20 |
-08:28:58.1 |
HIP 22693 |
27.00 |
| 2026-02-16 00:00 |
04:54:26.57 |
-08:28:45.5 |
HIP 22693 |
26.94 |
| 2026-02-16 12:00 |
04:54:25.96 |
-08:28:32.7 |
HIP 22693 |
26.89 |
| 2026-02-17 00:00 |
04:54:25.37 |
-08:28:20.0 |
HIP 22693 |
26.84 |
| 2026-02-17 12:00 |
04:54:24.79 |
-08:28:07.1 |
HIP 22693 |
26.80 |
| 2026-02-18 00:00 |
04:54:24.22 |
-08:27:54.3 |
HIP 22693 |
26.76 |
| 2026-02-18 12:00 |
04:54:23.68 |
-08:27:41.3 |
HIP 22693 |
26.73 |
| 2026-02-19 00:00 |
04:54:23.14 |
-08:27:28.4 |
HIP 22693 |
26.71 |
| 2026-02-19 12:00 |
04:54:22.63 |
-08:27:15.3 |
HIP 22693 |
26.69 |
| 2026-02-20 00:00 |
04:54:22.13 |
-08:27:02.3 |
HIP 22693 |
26.68 |
| 2026-02-20 12:00 |
04:54:21.64 |
-08:26:49.1 |
HIP 22693 |
26.68 |
| 2026-02-21 00:00 |
04:54:21.17 |
-08:26:35.9 |
HIP 22693 |
26.68 |
| 2026-02-21 12:00 |
04:54:20.72 |
-08:26:22.7 |
HIP 22693 |
26.69 |
| 2026-02-22 00:00 |
04:54:20.28 |
-08:26:09.5 |
HIP 22693 |
26.70 |
| 2026-02-22 12:00 |
04:54:19.86 |
-08:25:56.1 |
HIP 22693 |
26.72 |
| 2026-02-23 00:00 |
04:54:19.46 |
-08:25:42.8 |
HIP 22693 |
26.75 |
| 2026-02-23 12:00 |
04:54:19.07 |
-08:25:29.4 |
HIP 22693 |
26.78 |
| 2026-02-24 00:00 |
04:54:18.69 |
-08:25:16.0 |
HIP 22693 |
26.82 |