| 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) |
| 2026-07-29 00:00 |
04:35:23.89 |
+37:43:34.5 |
HIP 21387 |
13.63 |
| 2026-07-29 12:00 |
04:35:25.92 |
+37:43:45.3 |
HIP 21387 |
13.81 |
| 2026-07-30 00:00 |
04:35:27.92 |
+37:43:56.2 |
HIP 21387 |
14.01 |
| 2026-07-30 12:00 |
04:35:29.90 |
+37:44:07.1 |
HIP 21387 |
14.21 |
| 2026-07-31 00:00 |
04:35:31.86 |
+37:44:18.0 |
HIP 21387 |
14.43 |
| 2026-07-31 12:00 |
04:35:33.79 |
+37:44:28.9 |
HIP 21387 |
14.65 |
| 2026-08-01 00:00 |
04:35:35.71 |
+37:44:39.8 |
HIP 21387 |
14.89 |
| 2026-08-01 12:00 |
04:35:37.60 |
+37:44:50.7 |
HIP 21387 |
15.13 |
| 2026-08-02 00:00 |
04:35:39.46 |
+37:45:01.6 |
HIP 21387 |
15.37 |
| 2026-08-02 12:00 |
04:35:41.30 |
+37:45:12.6 |
HIP 21387 |
15.63 |
| 2026-08-03 00:00 |
04:35:43.12 |
+37:45:23.5 |
HIP 21387 |
15.88 |
| 2026-08-03 12:00 |
04:35:44.92 |
+37:45:34.5 |
HIP 21387 |
16.15 |
| 2026-08-04 00:00 |
04:35:46.69 |
+37:45:45.5 |
HIP 21387 |
16.41 |
| 2026-08-04 12:00 |
04:35:48.43 |
+37:45:56.4 |
HIP 21387 |
16.68 |
| 2026-08-05 00:00 |
04:35:50.16 |
+37:46:07.4 |
HIP 21387 |
16.96 |
| 2026-08-05 12:00 |
04:35:51.86 |
+37:46:18.4 |
HIP 21387 |
17.24 |
| 2026-08-06 00:00 |
04:35:53.53 |
+37:46:29.4 |
HIP 21387 |
17.52 |
| 2026-08-06 12:00 |
04:35:55.18 |
+37:46:40.4 |
HIP 21387 |
17.80 |
| 2026-08-07 00:00 |
04:35:56.80 |
+37:46:51.3 |
HIP 21387 |
18.08 |
| 2026-08-07 12:00 |
04:35:58.40 |
+37:47:02.3 |
HIP 21387 |
18.37 |
| 2026-08-08 00:00 |
04:35:59.98 |
+37:47:13.3 |
HIP 21387 |
18.65 |
| 2026-08-08 12:00 |
04:36:01.53 |
+37:47:24.3 |
HIP 21387 |
18.94 |
| 2026-08-09 00:00 |
04:36:03.05 |
+37:47:35.3 |
HIP 21387 |
19.23 |
| 2026-08-09 12:00 |
04:36:04.55 |
+37:47:46.3 |
HIP 21387 |
19.51 |
| 2026-08-10 00:00 |
04:36:06.03 |
+37:47:57.3 |
HIP 21387 |
19.80 |
| 2026-08-10 12:00 |
04:36:07.48 |
+37:48:08.2 |
HIP 21387 |
20.09 |
| 2026-08-11 00:00 |
04:36:08.90 |
+37:48:19.2 |
HIP 21387 |
20.37 |
| 2026-08-11 12:00 |
04:36:10.29 |
+37:48:30.2 |
HIP 21387 |
20.66 |
| 2026-08-12 00:00 |
04:36:11.66 |
+37:48:41.1 |
HIP 21387 |
20.94 |
| 2026-08-12 12:00 |
04:36:13.01 |
+37:48:52.1 |
HIP 21387 |
21.22 |
| 2026-08-13 00:00 |
04:36:14.33 |
+37:49:03.0 |
HIP 21387 |
21.50 |
| 2026-08-13 12:00 |
04:36:15.62 |
+37:49:14.0 |
HIP 21387 |
21.78 |
| 2026-08-14 00:00 |
04:36:16.88 |
+37:49:24.9 |
HIP 21387 |
22.06 |
| 2026-08-14 12:00 |
04:36:18.12 |
+37:49:35.8 |
HIP 21387 |
22.34 |
| 2026-08-15 00:00 |
04:36:19.33 |
+37:49:46.7 |
HIP 21387 |
22.61 |
| 2026-08-15 12:00 |
04:36:20.52 |
+37:49:57.6 |
HIP 21387 |
22.88 |
| 2026-08-16 00:00 |
04:36:21.68 |
+37:50:08.5 |
HIP 21565 |
22.65 |
| 2026-08-16 12:00 |
04:36:22.81 |
+37:50:19.3 |
HIP 21565 |
22.37 |
| 2026-08-17 00:00 |
04:36:23.91 |
+37:50:30.2 |
HIP 21565 |
22.08 |
| 2026-08-17 12:00 |
04:36:24.99 |
+37:50:41.0 |
HIP 21565 |
21.81 |
| 2026-08-18 00:00 |
04:36:26.04 |
+37:50:51.8 |
HIP 21565 |
21.53 |
| 2026-08-18 12:00 |
04:36:27.06 |
+37:51:02.6 |
HIP 21565 |
21.26 |
| 2026-08-19 00:00 |
04:36:28.06 |
+37:51:13.4 |
HIP 21565 |
20.99 |