| Parameter |
Value |
| Designation |
C/2003 H3 (NEAT) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2003-04-24T05:32:24.740160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:29Z |
| Obs used |
765 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
5.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-08-01.0000000 |
| e |
0.99978175 |
| q (au) |
2.901439 |
| a (au) |
13294.090063 |
| i (deg) |
42.811675 |
| Ω (om, deg) |
269.417235 |
| ω (w, deg) |
6.477416 |
| M (ma, deg) |
0.000064 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.461 + 2.567\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.461 |
| n |
2.567 |
| gf |
1.000 |
| gb |
-0.709 |
| 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) |
| 2026-06-01 00:00 |
04:29:39.67 |
+37:27:06.4 |
HIP 21117 |
25.58 |
| 2026-06-01 12:00 |
04:29:43.14 |
+37:27:11.3 |
HIP 21117 |
24.94 |
| 2026-06-02 00:00 |
04:29:46.61 |
+37:27:16.3 |
HIP 21117 |
24.30 |
| 2026-06-02 12:00 |
04:29:50.07 |
+37:27:21.3 |
HIP 21117 |
23.66 |
| 2026-06-03 00:00 |
04:29:53.54 |
+37:27:26.4 |
HIP 21117 |
23.02 |
| 2026-06-03 12:00 |
04:29:57.00 |
+37:27:31.7 |
HIP 21117 |
22.39 |
| 2026-06-04 00:00 |
04:30:00.46 |
+37:27:36.9 |
HIP 21117 |
21.76 |
| 2026-06-04 12:00 |
04:30:03.92 |
+37:27:42.3 |
HIP 21117 |
21.13 |
| 2026-06-05 00:00 |
04:30:07.38 |
+37:27:47.8 |
HIP 21117 |
20.51 |
| 2026-06-05 12:00 |
04:30:10.84 |
+37:27:53.3 |
HIP 21117 |
19.89 |
| 2026-06-06 00:00 |
04:30:14.29 |
+37:27:58.9 |
HIP 21117 |
19.27 |
| 2026-06-06 12:00 |
04:30:17.74 |
+37:28:04.6 |
HIP 21117 |
18.66 |
| 2026-06-07 00:00 |
04:30:21.19 |
+37:28:10.4 |
HIP 21117 |
18.06 |
| 2026-06-07 12:00 |
04:30:24.63 |
+37:28:16.2 |
HIP 21117 |
17.46 |
| 2026-06-08 00:00 |
04:30:28.07 |
+37:28:22.2 |
HIP 21117 |
16.87 |
| 2026-06-08 12:00 |
04:30:31.51 |
+37:28:28.2 |
HIP 21117 |
16.28 |
| 2026-06-09 00:00 |
04:30:34.94 |
+37:28:34.2 |
HIP 21117 |
15.71 |
| 2026-06-09 12:00 |
04:30:38.37 |
+37:28:40.4 |
HIP 21117 |
15.14 |
| 2026-06-10 00:00 |
04:30:41.80 |
+37:28:46.6 |
HIP 21117 |
14.58 |
| 2026-06-10 12:00 |
04:30:45.22 |
+37:28:52.9 |
HIP 21117 |
14.04 |
| 2026-06-11 00:00 |
04:30:48.63 |
+37:28:59.3 |
HIP 21117 |
13.51 |
| 2026-06-11 12:00 |
04:30:52.05 |
+37:29:05.8 |
HIP 21117 |
12.99 |
| 2026-06-12 00:00 |
04:30:55.45 |
+37:29:12.3 |
HIP 21117 |
12.48 |
| 2026-06-12 12:00 |
04:30:58.85 |
+37:29:18.9 |
HIP 21117 |
12.00 |
| 2026-06-13 00:00 |
04:31:02.25 |
+37:29:25.6 |
HIP 21117 |
11.53 |
| 2026-06-13 12:00 |
04:31:05.64 |
+37:29:32.3 |
HIP 21117 |
11.09 |
| 2026-06-14 00:00 |
04:31:09.02 |
+37:29:39.2 |
HIP 21117 |
10.67 |
| 2026-06-14 12:00 |
04:31:12.40 |
+37:29:46.1 |
HIP 21117 |
10.27 |
| 2026-06-15 00:00 |
04:31:15.77 |
+37:29:53.0 |
HIP 21117 |
9.91 |
| 2026-06-15 12:00 |
04:31:19.14 |
+37:30:00.1 |
HIP 21117 |
9.58 |
| 2026-06-16 00:00 |
04:31:22.49 |
+37:30:07.2 |
HIP 21117 |
9.29 |
| 2026-06-16 12:00 |
04:31:25.84 |
+37:30:14.3 |
HIP 21117 |
9.04 |
| 2026-06-17 00:00 |
04:31:29.19 |
+37:30:21.6 |
HIP 21117 |
8.83 |
| 2026-06-17 12:00 |
04:31:32.52 |
+37:30:28.9 |
HIP 21117 |
8.67 |
| 2026-06-18 00:00 |
04:31:35.85 |
+37:30:36.3 |
HIP 21117 |
8.55 |
| 2026-06-18 12:00 |
04:31:39.17 |
+37:30:43.7 |
HIP 21117 |
8.49 |
| 2026-06-19 00:00 |
04:31:42.48 |
+37:30:51.2 |
HIP 21117 |
8.48 |
| 2026-06-19 12:00 |
04:31:45.78 |
+37:30:58.8 |
HIP 21117 |
8.52 |
| 2026-06-20 00:00 |
04:31:49.08 |
+37:31:06.5 |
HIP 21117 |
8.61 |
| 2026-06-20 12:00 |
04:31:52.36 |
+37:31:14.2 |
HIP 21117 |
8.74 |
| 2026-06-21 00:00 |
04:31:55.64 |
+37:31:21.9 |
HIP 21117 |
8.93 |
| 2026-06-21 12:00 |
04:31:58.90 |
+37:31:29.8 |
HIP 21117 |
9.15 |
| 2026-06-22 00:00 |
04:32:02.16 |
+37:31:37.7 |
HIP 21117 |
9.42 |