| 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) |
| 2026-07-29 00:00 |
05:00:13.77 |
-07:54:16.3 |
HIP 23230 |
6.97 |
| 2026-07-29 12:00 |
05:00:14.87 |
-07:54:24.9 |
HIP 23230 |
7.26 |
| 2026-07-30 00:00 |
05:00:15.95 |
-07:54:33.7 |
HIP 23230 |
7.55 |
| 2026-07-30 12:00 |
05:00:17.01 |
-07:54:42.5 |
HIP 23230 |
7.85 |
| 2026-07-31 00:00 |
05:00:18.07 |
-07:54:51.5 |
HIP 23230 |
8.14 |
| 2026-07-31 12:00 |
05:00:19.12 |
-07:55:00.5 |
HIP 23230 |
8.43 |
| 2026-08-01 00:00 |
05:00:20.15 |
-07:55:09.6 |
HIP 23230 |
8.73 |
| 2026-08-01 12:00 |
05:00:21.18 |
-07:55:18.8 |
HIP 23230 |
9.02 |
| 2026-08-02 00:00 |
05:00:22.19 |
-07:55:28.1 |
HIP 23230 |
9.31 |
| 2026-08-02 12:00 |
05:00:23.19 |
-07:55:37.5 |
HIP 23230 |
9.60 |
| 2026-08-03 00:00 |
05:00:24.18 |
-07:55:46.9 |
HIP 23230 |
9.89 |
| 2026-08-03 12:00 |
05:00:25.16 |
-07:55:56.5 |
HIP 23230 |
10.17 |
| 2026-08-04 00:00 |
05:00:26.12 |
-07:56:06.1 |
HIP 23230 |
10.46 |
| 2026-08-04 12:00 |
05:00:27.07 |
-07:56:15.8 |
HIP 23230 |
10.74 |
| 2026-08-05 00:00 |
05:00:28.01 |
-07:56:25.6 |
HIP 23230 |
11.03 |
| 2026-08-05 12:00 |
05:00:28.94 |
-07:56:35.4 |
HIP 23230 |
11.31 |
| 2026-08-06 00:00 |
05:00:29.86 |
-07:56:45.4 |
HIP 23230 |
11.59 |
| 2026-08-06 12:00 |
05:00:30.76 |
-07:56:55.4 |
HIP 23230 |
11.87 |
| 2026-08-07 00:00 |
05:00:31.65 |
-07:57:05.5 |
HIP 23230 |
12.14 |
| 2026-08-07 12:00 |
05:00:32.53 |
-07:57:15.7 |
HIP 23230 |
12.42 |
| 2026-08-08 00:00 |
05:00:33.40 |
-07:57:26.0 |
HIP 23230 |
12.70 |
| 2026-08-08 12:00 |
05:00:34.26 |
-07:57:36.3 |
HIP 23230 |
12.97 |
| 2026-08-09 00:00 |
05:00:35.10 |
-07:57:46.7 |
HIP 23230 |
13.24 |
| 2026-08-09 12:00 |
05:00:35.93 |
-07:57:57.2 |
HIP 23230 |
13.51 |
| 2026-08-10 00:00 |
05:00:36.74 |
-07:58:07.8 |
HIP 23230 |
13.78 |
| 2026-08-10 12:00 |
05:00:37.54 |
-07:58:18.4 |
HIP 23230 |
14.04 |
| 2026-08-11 00:00 |
05:00:38.33 |
-07:58:29.2 |
HIP 23230 |
14.31 |
| 2026-08-11 12:00 |
05:00:39.11 |
-07:58:39.9 |
HIP 23230 |
14.57 |
| 2026-08-12 00:00 |
05:00:39.87 |
-07:58:50.8 |
HIP 23230 |
14.83 |
| 2026-08-12 12:00 |
05:00:40.62 |
-07:59:01.8 |
HIP 23230 |
15.09 |
| 2026-08-13 00:00 |
05:00:41.36 |
-07:59:12.8 |
HIP 23230 |
15.35 |
| 2026-08-13 12:00 |
05:00:42.09 |
-07:59:23.9 |
HIP 23230 |
15.61 |
| 2026-08-14 00:00 |
05:00:42.80 |
-07:59:35.0 |
HIP 23230 |
15.86 |
| 2026-08-14 12:00 |
05:00:43.49 |
-07:59:46.2 |
HIP 23230 |
16.11 |
| 2026-08-15 00:00 |
05:00:44.18 |
-07:59:57.5 |
HIP 23230 |
16.36 |
| 2026-08-15 12:00 |
05:00:44.85 |
-08:00:08.9 |
HIP 23230 |
16.61 |
| 2026-08-16 00:00 |
05:00:45.50 |
-08:00:20.3 |
HIP 23230 |
16.86 |
| 2026-08-16 12:00 |
05:00:46.14 |
-08:00:31.8 |
HIP 23230 |
17.10 |
| 2026-08-17 00:00 |
05:00:46.77 |
-08:00:43.3 |
HIP 23230 |
17.35 |
| 2026-08-17 12:00 |
05:00:47.39 |
-08:00:54.9 |
HIP 23230 |
17.59 |
| 2026-08-18 00:00 |
05:00:47.99 |
-08:01:06.6 |
HIP 23230 |
17.83 |
| 2026-08-18 12:00 |
05:00:48.57 |
-08:01:18.4 |
HIP 23230 |
18.07 |
| 2026-08-19 00:00 |
05:00:49.15 |
-08:01:30.2 |
HIP 23230 |
18.30 |