| 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) |
| 2026-05-12 00:00 |
04:56:10.92 |
-07:53:12.3 |
HIP 22909 |
6.28 |
| 2026-05-12 12:00 |
04:56:12.49 |
-07:53:04.3 |
HIP 22909 |
6.68 |
| 2026-05-13 00:00 |
04:56:14.06 |
-07:52:56.5 |
HIP 22909 |
7.08 |
| 2026-05-13 12:00 |
04:56:15.64 |
-07:52:48.8 |
HIP 22909 |
7.48 |
| 2026-05-14 00:00 |
04:56:17.22 |
-07:52:41.1 |
HIP 22909 |
7.88 |
| 2026-05-14 12:00 |
04:56:18.81 |
-07:52:33.6 |
HIP 22909 |
8.29 |
| 2026-05-15 00:00 |
04:56:20.40 |
-07:52:26.1 |
HIP 22909 |
8.70 |
| 2026-05-15 12:00 |
04:56:22.00 |
-07:52:18.8 |
HIP 22909 |
9.11 |
| 2026-05-16 00:00 |
04:56:23.60 |
-07:52:11.5 |
HIP 22909 |
9.52 |
| 2026-05-16 12:00 |
04:56:25.21 |
-07:52:04.4 |
HIP 22909 |
9.93 |
| 2026-05-17 00:00 |
04:56:26.83 |
-07:51:57.3 |
HIP 22909 |
10.34 |
| 2026-05-17 12:00 |
04:56:28.45 |
-07:51:50.4 |
HIP 22909 |
10.76 |
| 2026-05-18 00:00 |
04:56:30.07 |
-07:51:43.5 |
HIP 22909 |
11.17 |
| 2026-05-18 12:00 |
04:56:31.70 |
-07:51:36.8 |
HIP 22909 |
11.59 |
| 2026-05-19 00:00 |
04:56:33.33 |
-07:51:30.2 |
HIP 22909 |
12.01 |
| 2026-05-19 12:00 |
04:56:34.97 |
-07:51:23.6 |
HIP 22909 |
12.43 |
| 2026-05-20 00:00 |
04:56:36.61 |
-07:51:17.2 |
HIP 22909 |
12.85 |
| 2026-05-20 12:00 |
04:56:38.26 |
-07:51:10.9 |
HIP 22909 |
13.27 |
| 2026-05-21 00:00 |
04:56:39.91 |
-07:51:04.6 |
HIP 22909 |
13.69 |
| 2026-05-21 12:00 |
04:56:41.56 |
-07:50:58.5 |
HIP 22909 |
14.11 |
| 2026-05-22 00:00 |
04:56:43.22 |
-07:50:52.5 |
HIP 22909 |
14.53 |
| 2026-05-22 12:00 |
04:56:44.88 |
-07:50:46.6 |
HIP 22909 |
14.95 |
| 2026-05-23 00:00 |
04:56:46.54 |
-07:50:40.8 |
HIP 22909 |
15.38 |
| 2026-05-23 12:00 |
04:56:48.21 |
-07:50:35.1 |
HIP 22909 |
15.80 |
| 2026-05-24 00:00 |
04:56:49.88 |
-07:50:29.5 |
HIP 22909 |
16.22 |
| 2026-05-24 12:00 |
04:56:51.55 |
-07:50:24.0 |
HIP 22909 |
16.65 |
| 2026-05-25 00:00 |
04:56:53.23 |
-07:50:18.6 |
HIP 22909 |
17.07 |
| 2026-05-25 12:00 |
04:56:54.91 |
-07:50:13.3 |
HIP 22909 |
17.50 |
| 2026-05-26 00:00 |
04:56:56.59 |
-07:50:08.1 |
HIP 22909 |
17.92 |
| 2026-05-26 12:00 |
04:56:58.28 |
-07:50:03.1 |
HIP 22909 |
18.35 |
| 2026-05-27 00:00 |
04:56:59.97 |
-07:49:58.1 |
HIP 22909 |
18.77 |
| 2026-05-27 12:00 |
04:57:01.66 |
-07:49:53.2 |
HIP 22909 |
19.20 |
| 2026-05-28 00:00 |
04:57:03.35 |
-07:49:48.5 |
HIP 22909 |
19.63 |
| 2026-05-28 12:00 |
04:57:05.04 |
-07:49:43.8 |
HIP 22909 |
20.05 |
| 2026-05-29 00:00 |
04:57:06.74 |
-07:49:39.3 |
HIP 22909 |
20.48 |
| 2026-05-29 12:00 |
04:57:08.44 |
-07:49:34.9 |
HIP 22909 |
20.91 |
| 2026-05-30 00:00 |
04:57:10.14 |
-07:49:30.6 |
HIP 22909 |
21.34 |
| 2026-05-30 12:00 |
04:57:11.84 |
-07:49:26.4 |
HIP 22909 |
21.76 |
| 2026-05-31 00:00 |
04:57:13.55 |
-07:49:22.3 |
HIP 22909 |
22.19 |
| 2026-05-31 12:00 |
04:57:15.25 |
-07:49:18.3 |
HIP 22909 |
22.62 |
| 2026-06-01 00:00 |
04:57:16.96 |
-07:49:14.4 |
HIP 22909 |
23.04 |
| 2026-06-01 12:00 |
04:57:18.67 |
-07:49:10.6 |
HIP 22909 |
23.47 |
| 2026-06-02 00:00 |
04:57:20.38 |
-07:49:07.0 |
HIP 22909 |
23.90 |