| 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) |
| 2026-03-26 00:00 |
04:54:24.89 |
-08:11:15.5 |
HIP 22909 |
26.65 |
| 2026-03-26 12:00 |
04:54:25.46 |
-08:11:01.5 |
HIP 22909 |
26.39 |
| 2026-03-27 00:00 |
04:54:26.04 |
-08:10:47.7 |
HIP 22909 |
26.13 |
| 2026-03-27 12:00 |
04:54:26.64 |
-08:10:33.8 |
HIP 22909 |
25.86 |
| 2026-03-28 00:00 |
04:54:27.25 |
-08:10:19.9 |
HIP 22909 |
25.60 |
| 2026-03-28 12:00 |
04:54:27.88 |
-08:10:06.1 |
HIP 22909 |
25.33 |
| 2026-03-29 00:00 |
04:54:28.51 |
-08:09:52.3 |
HIP 22909 |
25.06 |
| 2026-03-29 12:00 |
04:54:29.17 |
-08:09:38.6 |
HIP 22909 |
24.79 |
| 2026-03-30 00:00 |
04:54:29.83 |
-08:09:24.9 |
HIP 22909 |
24.52 |
| 2026-03-30 12:00 |
04:54:30.51 |
-08:09:11.2 |
HIP 22909 |
24.24 |
| 2026-03-31 00:00 |
04:54:31.21 |
-08:08:57.5 |
HIP 22909 |
23.96 |
| 2026-03-31 12:00 |
04:54:31.92 |
-08:08:43.9 |
HIP 22909 |
23.68 |
| 2026-04-01 00:00 |
04:54:32.64 |
-08:08:30.3 |
HIP 22909 |
23.40 |
| 2026-04-01 12:00 |
04:54:33.38 |
-08:08:16.7 |
HIP 22909 |
23.12 |
| 2026-04-02 00:00 |
04:54:34.12 |
-08:08:03.2 |
HIP 22909 |
22.83 |
| 2026-04-02 12:00 |
04:54:34.89 |
-08:07:49.7 |
HIP 22909 |
22.54 |
| 2026-04-03 00:00 |
04:54:35.66 |
-08:07:36.3 |
HIP 22909 |
22.25 |
| 2026-04-03 12:00 |
04:54:36.45 |
-08:07:22.9 |
HIP 22909 |
21.96 |
| 2026-04-04 00:00 |
04:54:37.26 |
-08:07:09.5 |
HIP 22909 |
21.67 |
| 2026-04-04 12:00 |
04:54:38.07 |
-08:06:56.2 |
HIP 22909 |
21.37 |
| 2026-04-05 00:00 |
04:54:38.90 |
-08:06:42.9 |
HIP 22909 |
21.07 |
| 2026-04-05 12:00 |
04:54:39.74 |
-08:06:29.6 |
HIP 22909 |
20.77 |
| 2026-04-06 00:00 |
04:54:40.60 |
-08:06:16.4 |
HIP 22909 |
20.47 |
| 2026-04-06 12:00 |
04:54:41.47 |
-08:06:03.2 |
HIP 22909 |
20.16 |
| 2026-04-07 00:00 |
04:54:42.35 |
-08:05:50.1 |
HIP 22909 |
19.86 |
| 2026-04-07 12:00 |
04:54:43.24 |
-08:05:37.1 |
HIP 22909 |
19.55 |
| 2026-04-08 00:00 |
04:54:44.15 |
-08:05:24.0 |
HIP 22909 |
19.24 |
| 2026-04-08 12:00 |
04:54:45.07 |
-08:05:11.1 |
HIP 22909 |
18.93 |
| 2026-04-09 00:00 |
04:54:46.00 |
-08:04:58.1 |
HIP 22909 |
18.61 |
| 2026-04-09 12:00 |
04:54:46.95 |
-08:04:45.2 |
HIP 22909 |
18.29 |
| 2026-04-10 00:00 |
04:54:47.90 |
-08:04:32.4 |
HIP 22909 |
17.98 |
| 2026-04-10 12:00 |
04:54:48.87 |
-08:04:19.6 |
HIP 22909 |
17.66 |
| 2026-04-11 00:00 |
04:54:49.85 |
-08:04:06.9 |
HIP 22909 |
17.33 |
| 2026-04-11 12:00 |
04:54:50.85 |
-08:03:54.2 |
HIP 22909 |
17.01 |
| 2026-04-12 00:00 |
04:54:51.85 |
-08:03:41.6 |
HIP 22909 |
16.69 |
| 2026-04-12 12:00 |
04:54:52.87 |
-08:03:29.0 |
HIP 22909 |
16.36 |
| 2026-04-13 00:00 |
04:54:53.90 |
-08:03:16.5 |
HIP 22909 |
16.03 |
| 2026-04-13 12:00 |
04:54:54.95 |
-08:03:04.0 |
HIP 22909 |
15.70 |
| 2026-04-14 00:00 |
04:54:56.00 |
-08:02:51.6 |
HIP 22909 |
15.36 |
| 2026-04-14 12:00 |
04:54:57.07 |
-08:02:39.3 |
HIP 22909 |
15.03 |
| 2026-04-15 00:00 |
04:54:58.14 |
-08:02:27.0 |
HIP 22909 |
14.69 |
| 2026-04-15 12:00 |
04:54:59.23 |
-08:02:14.8 |
HIP 22909 |
14.36 |
| 2026-04-16 00:00 |
04:55:00.33 |
-08:02:02.6 |
HIP 22909 |
14.02 |