C/2003 E1 (NEAT)
| Parameter |
Value |
| Designation |
C/2003 E1 (NEAT) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-02-13T14:31:17.322240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:26Z |
| Obs used |
235 |
| NEO |
- |
| M1 |
13.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-10-15.0000000 |
| e |
0.76358329 |
| q (au) |
3.244959 |
| a (au) |
13.725590 |
| i (deg) |
33.537820 |
| Ω (om, deg) |
137.069987 |
| ω (w, deg) |
103.859277 |
| M (ma, deg) |
357.643002 |
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 |
-0.500 |
| 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 |
-7.341 |
| 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) |
| 2026-02-03 00:00 |
04:01:08.17 |
-13:28:07.4 |
HIP 18796 |
22.55 |
| 2026-02-03 12:00 |
04:01:07.03 |
-13:27:28.9 |
HIP 18796 |
23.24 |
| 2026-02-04 00:00 |
04:01:05.93 |
-13:26:50.2 |
HIP 18796 |
23.94 |
| 2026-02-04 12:00 |
04:01:04.87 |
-13:26:11.3 |
HIP 18796 |
24.64 |
| 2026-02-05 00:00 |
04:01:03.85 |
-13:25:32.3 |
HIP 18796 |
25.33 |
| 2026-02-05 12:00 |
04:01:02.88 |
-13:24:53.0 |
HIP 18796 |
26.03 |
| 2026-02-06 00:00 |
04:01:01.95 |
-13:24:13.6 |
HIP 18796 |
26.72 |
| 2026-02-06 12:00 |
04:01:01.06 |
-13:23:34.0 |
HIP 18796 |
27.42 |
| 2026-02-07 00:00 |
04:01:00.21 |
-13:22:54.3 |
HIP 18796 |
28.11 |
| 2026-02-07 12:00 |
04:00:59.41 |
-13:22:14.3 |
HIP 18796 |
28.80 |
| 2026-02-08 00:00 |
04:00:58.66 |
-13:21:34.2 |
HIP 18796 |
29.50 |
| 2026-02-08 12:00 |
04:00:57.94 |
-13:20:53.9 |
HIP 18722 |
29.65 |
| 2026-02-09 00:00 |
04:00:57.27 |
-13:20:13.5 |
HIP 18722 |
28.96 |
| 2026-02-09 12:00 |
04:00:56.64 |
-13:19:32.9 |
HIP 18722 |
28.27 |
| 2026-02-10 00:00 |
04:00:56.06 |
-13:18:52.1 |
HIP 18722 |
27.57 |
| 2026-02-10 12:00 |
04:00:55.52 |
-13:18:11.2 |
HIP 18722 |
26.88 |
| 2026-02-11 00:00 |
04:00:55.02 |
-13:17:30.1 |
HIP 18722 |
26.18 |
| 2026-02-11 12:00 |
04:00:54.57 |
-13:16:48.9 |
HIP 18722 |
25.49 |
| 2026-02-12 00:00 |
04:00:54.16 |
-13:16:07.5 |
HIP 18722 |
24.79 |
| 2026-02-12 12:00 |
04:00:53.79 |
-13:15:26.0 |
HIP 18722 |
24.09 |
| 2026-02-13 00:00 |
04:00:53.47 |
-13:14:44.4 |
HIP 18722 |
23.40 |
| 2026-02-13 12:00 |
04:00:53.19 |
-13:14:02.6 |
HIP 18722 |
22.70 |
| 2026-02-14 00:00 |
04:00:52.96 |
-13:13:20.7 |
HIP 18722 |
22.00 |
| 2026-02-14 12:00 |
04:00:52.77 |
-13:12:38.7 |
HIP 18722 |
21.30 |
| 2026-02-15 00:00 |
04:00:52.62 |
-13:11:56.5 |
HIP 18722 |
20.60 |
| 2026-02-15 12:00 |
04:00:52.52 |
-13:11:14.2 |
HIP 18722 |
19.90 |
| 2026-02-16 00:00 |
04:00:52.46 |
-13:10:31.8 |
HIP 18722 |
19.20 |
| 2026-02-16 12:00 |
04:00:52.45 |
-13:09:49.3 |
HIP 18722 |
18.50 |
| 2026-02-17 00:00 |
04:00:52.48 |
-13:09:06.7 |
HIP 18722 |
17.80 |
| 2026-02-17 12:00 |
04:00:52.55 |
-13:08:23.9 |
HIP 18722 |
17.10 |
| 2026-02-18 00:00 |
04:00:52.66 |
-13:07:41.1 |
HIP 18722 |
16.40 |
| 2026-02-18 12:00 |
04:00:52.82 |
-13:06:58.2 |
HIP 18722 |
15.71 |
| 2026-02-19 00:00 |
04:00:53.03 |
-13:06:15.1 |
HIP 18722 |
15.01 |
| 2026-02-19 12:00 |
04:00:53.28 |
-13:05:32.0 |
HIP 18722 |
14.33 |
| 2026-02-20 00:00 |
04:00:53.57 |
-13:04:48.7 |
HIP 18722 |
13.64 |
| 2026-02-20 12:00 |
04:00:53.90 |
-13:04:05.4 |
HIP 18722 |
12.96 |
| 2026-02-21 00:00 |
04:00:54.28 |
-13:03:22.0 |
HIP 18722 |
12.29 |
| 2026-02-21 12:00 |
04:00:54.70 |
-13:02:38.5 |
HIP 18722 |
11.63 |
| 2026-02-22 00:00 |
04:00:55.17 |
-13:01:55.0 |
HIP 18722 |
10.98 |
| 2026-02-22 12:00 |
04:00:55.67 |
-13:01:11.4 |
HIP 18722 |
10.34 |
| 2026-02-23 00:00 |
04:00:56.22 |
-13:00:27.7 |
HIP 18722 |
9.72 |
| 2026-02-23 12:00 |
04:00:56.82 |
-12:59:43.9 |
HIP 18722 |
9.12 |
| 2026-02-24 00:00 |
04:00:57.46 |
-12:59:00.1 |
HIP 18722 |
8.55 |