| Parameter |
Value |
| Designation |
28P/Neujmin 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-03-12T00:38:40.790400Z |
| Orbit solution date (soln_date, UTC) |
2026-03-09T10:05:19Z |
| Obs used |
1223 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-27.0000000 |
| e |
0.77347686 |
| q (au) |
1.577970 |
| a (au) |
6.966042 |
| i (deg) |
14.311570 |
| Ω (om, deg) |
346.346563 |
| ω (w, deg) |
347.441651 |
| M (ma, deg) |
331.479408 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.747 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.747 |
| n |
2.000 |
| gf |
0.893 |
| gb |
-0.726 |
| k |
0.937 |
| δ90 |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
09:04:50.92 |
+24:03:40.7 |
HIP 44718 |
32.32 |
| 2026-05-12 12:00 |
09:04:54.03 |
+24:03:01.7 |
HIP 44718 |
32.16 |
| 2026-05-13 00:00 |
09:04:57.24 |
+24:02:22.4 |
HIP 44718 |
32.02 |
| 2026-05-13 12:00 |
09:05:00.53 |
+24:01:42.8 |
HIP 44718 |
31.90 |
| 2026-05-14 00:00 |
09:05:03.92 |
+24:01:03.0 |
HIP 44718 |
31.80 |
| 2026-05-14 12:00 |
09:05:07.39 |
+24:00:22.8 |
HIP 44718 |
31.73 |
| 2026-05-15 00:00 |
09:05:10.96 |
+23:59:42.3 |
HIP 44718 |
31.67 |
| 2026-05-15 12:00 |
09:05:14.61 |
+23:59:01.5 |
HIP 44718 |
31.64 |
| 2026-05-16 00:00 |
09:05:18.35 |
+23:58:20.5 |
HIP 44718 |
31.64 |
| 2026-05-16 12:00 |
09:05:22.18 |
+23:57:39.1 |
HIP 44718 |
31.67 |
| 2026-05-17 00:00 |
09:05:26.09 |
+23:56:57.5 |
HIP 44718 |
31.74 |
| 2026-05-17 12:00 |
09:05:30.09 |
+23:56:15.6 |
HIP 44718 |
31.83 |
| 2026-05-18 00:00 |
09:05:34.18 |
+23:55:33.4 |
HIP 44718 |
31.96 |
| 2026-05-18 12:00 |
09:05:38.36 |
+23:54:50.9 |
HIP 44718 |
32.13 |
| 2026-05-19 00:00 |
09:05:42.62 |
+23:54:08.1 |
HIP 44718 |
32.33 |
| 2026-05-19 12:00 |
09:05:46.96 |
+23:53:25.1 |
HIP 44718 |
32.58 |
| 2026-05-20 00:00 |
09:05:51.39 |
+23:52:41.8 |
HIP 44718 |
32.87 |
| 2026-05-20 12:00 |
09:05:55.90 |
+23:51:58.2 |
HIP 44718 |
33.20 |
| 2026-05-21 00:00 |
09:06:00.50 |
+23:51:14.3 |
HIP 44718 |
33.57 |
| 2026-05-21 12:00 |
09:06:05.18 |
+23:50:30.2 |
HIP 44740 |
33.61 |
| 2026-05-22 00:00 |
09:06:09.94 |
+23:49:45.8 |
HIP 44740 |
32.51 |
| 2026-05-22 12:00 |
09:06:14.78 |
+23:49:01.2 |
HIP 44740 |
31.41 |
| 2026-05-23 00:00 |
09:06:19.71 |
+23:48:16.3 |
HIP 44740 |
30.33 |
| 2026-05-23 12:00 |
09:06:24.71 |
+23:47:31.2 |
HIP 44740 |
29.25 |
| 2026-05-24 00:00 |
09:06:29.80 |
+23:46:45.8 |
HIP 44740 |
28.20 |
| 2026-05-24 12:00 |
09:06:34.96 |
+23:46:00.2 |
HIP 44740 |
27.16 |
| 2026-05-25 00:00 |
09:06:40.21 |
+23:45:14.3 |
HIP 44740 |
26.16 |
| 2026-05-25 12:00 |
09:06:45.53 |
+23:44:28.1 |
HIP 44740 |
25.18 |
| 2026-05-26 00:00 |
09:06:50.93 |
+23:43:41.8 |
HIP 44740 |
24.25 |
| 2026-05-26 12:00 |
09:06:56.41 |
+23:42:55.2 |
HIP 44740 |
23.37 |
| 2026-05-27 00:00 |
09:07:01.97 |
+23:42:08.3 |
HIP 44740 |
22.54 |
| 2026-05-27 12:00 |
09:07:07.60 |
+23:41:21.2 |
HIP 44740 |
21.78 |
| 2026-05-28 00:00 |
09:07:13.31 |
+23:40:33.9 |
HIP 44740 |
21.11 |
| 2026-05-28 12:00 |
09:07:19.10 |
+23:39:46.4 |
HIP 44740 |
20.52 |
| 2026-05-29 00:00 |
09:07:24.96 |
+23:38:58.6 |
HIP 44740 |
20.04 |
| 2026-05-29 12:00 |
09:07:30.90 |
+23:38:10.6 |
HIP 44740 |
19.67 |
| 2026-05-30 00:00 |
09:07:36.91 |
+23:37:22.4 |
HIP 44740 |
19.42 |
| 2026-05-30 12:00 |
09:07:42.99 |
+23:36:33.9 |
HIP 44740 |
19.31 |
| 2026-05-31 00:00 |
09:07:49.15 |
+23:35:45.2 |
HIP 44740 |
19.34 |
| 2026-05-31 12:00 |
09:07:55.38 |
+23:34:56.4 |
HIP 44941 |
18.68 |
| 2026-06-01 00:00 |
09:08:01.69 |
+23:34:07.3 |
HIP 44941 |
17.08 |
| 2026-06-01 12:00 |
09:08:08.06 |
+23:33:17.9 |
HIP 44941 |
15.48 |
| 2026-06-02 00:00 |
09:08:14.51 |
+23:32:28.4 |
HIP 44941 |
13.88 |