| Parameter |
Value |
| Designation |
C/2003 E1 (NEAT) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-02-13T14:29:55.553280Z |
| Orbit solution date (soln_date, UTC) |
2026-07-06T12:12:23Z |
| Obs used |
238 |
| NEO |
- |
| M1 |
13.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-10-13.0000000 |
| e |
0.76358461 |
| q (au) |
3.244961 |
| a (au) |
13.725677 |
| i (deg) |
33.537822 |
| Ω (om, deg) |
137.069993 |
| ω (w, deg) |
103.859060 |
| M (ma, deg) |
357.604279 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.327 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.327 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.995 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2003-03-09 |
2004-02-05 |
+11.2722 |
-7.340 |
| 2004-02-21 |
2004-09-11 |
+21.5365 |
-11.046 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
04:22:54.87 |
-12:31:11.3 |
HIP 20523 |
14.48 |
| 2026-09-20 12:00 |
04:22:53.60 |
-12:31:51.6 |
HIP 20523 |
14.68 |
| 2026-09-21 00:00 |
04:22:52.29 |
-12:32:31.8 |
HIP 20523 |
14.93 |
| 2026-09-21 12:00 |
04:22:50.94 |
-12:33:12.1 |
HIP 20523 |
15.21 |
| 2026-09-22 00:00 |
04:22:49.54 |
-12:33:52.3 |
HIP 20523 |
15.54 |
| 2026-09-22 12:00 |
04:22:48.11 |
-12:34:32.5 |
HIP 20523 |
15.91 |
| 2026-09-23 00:00 |
04:22:46.63 |
-12:35:12.6 |
HIP 20523 |
16.31 |
| 2026-09-23 12:00 |
04:22:45.11 |
-12:35:52.7 |
HIP 20523 |
16.75 |
| 2026-09-24 00:00 |
04:22:43.56 |
-12:36:32.8 |
HIP 20523 |
17.22 |
| 2026-09-24 12:00 |
04:22:41.96 |
-12:37:12.8 |
HIP 20523 |
17.72 |
| 2026-09-25 00:00 |
04:22:40.32 |
-12:37:52.8 |
HIP 20523 |
18.24 |
| 2026-09-25 12:00 |
04:22:38.64 |
-12:38:32.7 |
HIP 20523 |
18.80 |
| 2026-09-26 00:00 |
04:22:36.93 |
-12:39:12.6 |
HIP 20523 |
19.38 |
| 2026-09-26 12:00 |
04:22:35.17 |
-12:39:52.4 |
HIP 20523 |
19.98 |
| 2026-09-27 00:00 |
04:22:33.37 |
-12:40:32.2 |
HIP 20523 |
20.61 |
| 2026-09-27 12:00 |
04:22:31.53 |
-12:41:11.9 |
HIP 20523 |
21.25 |
| 2026-09-28 00:00 |
04:22:29.65 |
-12:41:51.6 |
HIP 20523 |
21.92 |
| 2026-09-28 12:00 |
04:22:27.74 |
-12:42:31.1 |
HIP 20523 |
22.60 |
| 2026-09-29 00:00 |
04:22:25.78 |
-12:43:10.6 |
HIP 20523 |
23.29 |
| 2026-09-29 12:00 |
04:22:23.79 |
-12:43:50.1 |
HIP 20523 |
24.01 |
| 2026-09-30 00:00 |
04:22:21.75 |
-12:44:29.4 |
HIP 20523 |
24.73 |
| 2026-09-30 12:00 |
04:22:19.68 |
-12:45:08.7 |
HIP 20523 |
25.47 |
| 2026-10-01 00:00 |
04:22:17.56 |
-12:45:47.9 |
HIP 20523 |
26.23 |
| 2026-10-01 12:00 |
04:22:15.41 |
-12:46:27.0 |
HIP 20523 |
26.99 |
| 2026-10-02 00:00 |
04:22:13.22 |
-12:47:06.0 |
HIP 20523 |
27.77 |
| 2026-10-02 12:00 |
04:22:10.99 |
-12:47:44.9 |
HIP 20523 |
28.56 |
| 2026-10-03 00:00 |
04:22:08.72 |
-12:48:23.7 |
HIP 20523 |
29.36 |
| 2026-10-03 12:00 |
04:22:06.42 |
-12:49:02.4 |
HIP 20523 |
30.17 |
| 2026-10-04 00:00 |
04:22:04.07 |
-12:49:41.0 |
HIP 20523 |
30.99 |
| 2026-10-04 12:00 |
04:22:01.69 |
-12:50:19.6 |
HIP 20523 |
31.82 |
| 2026-10-05 00:00 |
04:21:59.27 |
-12:50:57.9 |
HIP 20523 |
32.65 |
| 2026-10-05 12:00 |
04:21:56.81 |
-12:51:36.2 |
HIP 20523 |
33.50 |
| 2026-10-06 00:00 |
04:21:54.32 |
-12:52:14.4 |
HIP 20523 |
34.35 |
| 2026-10-06 12:00 |
04:21:51.78 |
-12:52:52.4 |
HIP 20523 |
35.21 |
| 2026-10-07 00:00 |
04:21:49.21 |
-12:53:30.3 |
HIP 20523 |
36.08 |
| 2026-10-07 12:00 |
04:21:46.61 |
-12:54:08.1 |
HIP 20523 |
36.96 |
| 2026-10-08 00:00 |
04:21:43.96 |
-12:54:45.8 |
HIP 20523 |
37.84 |
| 2026-10-08 12:00 |
04:21:41.28 |
-12:55:23.3 |
HIP 20523 |
38.73 |
| 2026-10-09 00:00 |
04:21:38.57 |
-12:56:00.6 |
HIP 20523 |
39.63 |
| 2026-10-09 12:00 |
04:21:35.81 |
-12:56:37.9 |
HIP 20523 |
40.53 |
| 2026-10-10 00:00 |
04:21:33.02 |
-12:57:15.0 |
HIP 20212 |
41.19 |
| 2026-10-10 12:00 |
04:21:30.20 |
-12:57:51.9 |
HIP 20147 |
40.93 |
| 2026-10-11 00:00 |
04:21:27.34 |
-12:58:28.6 |
HIP 20147 |
40.01 |