| Parameter |
Value |
| Designation |
C/2003 H1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-02-22T14:57:51.929280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:29Z |
| Obs used |
1890 |
| NEO |
- |
| M1 |
11.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-08-30.0000000 |
| e |
0.99915679 |
| q (au) |
2.239626 |
| a (au) |
2656.070310 |
| i (deg) |
138.667213 |
| Ω (om, deg) |
19.000486 |
| ω (w, deg) |
196.139594 |
| M (ma, deg) |
359.998728 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.871 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.871 |
| n |
2.000 |
| gf |
0.989 |
| gb |
-0.730 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2003-04-24 |
2004-02-21 |
+3.5205 |
-2.057 |
| 2004-02-23 |
2005-02-07 |
+17.2256 |
-6.015 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
01:47:49.20 |
+03:55:57.6 |
HIP 8329 |
6.82 |
| 2026-03-26 12:00 |
01:47:51.43 |
+03:56:13.7 |
HIP 8329 |
7.41 |
| 2026-03-27 00:00 |
01:47:53.66 |
+03:56:29.8 |
HIP 8329 |
8.00 |
| 2026-03-27 12:00 |
01:47:55.90 |
+03:56:45.9 |
HIP 8329 |
8.60 |
| 2026-03-28 00:00 |
01:47:58.15 |
+03:57:02.0 |
HIP 8329 |
9.21 |
| 2026-03-28 12:00 |
01:48:00.40 |
+03:57:18.1 |
HIP 8329 |
9.81 |
| 2026-03-29 00:00 |
01:48:02.67 |
+03:57:34.3 |
HIP 8329 |
10.43 |
| 2026-03-29 12:00 |
01:48:04.94 |
+03:57:50.4 |
HIP 8329 |
11.04 |
| 2026-03-30 00:00 |
01:48:07.22 |
+03:58:06.5 |
HIP 8329 |
11.66 |
| 2026-03-30 12:00 |
01:48:09.50 |
+03:58:22.6 |
HIP 8329 |
12.28 |
| 2026-03-31 00:00 |
01:48:11.79 |
+03:58:38.7 |
HIP 8329 |
12.90 |
| 2026-03-31 12:00 |
01:48:14.09 |
+03:58:54.8 |
HIP 8329 |
13.53 |
| 2026-04-01 00:00 |
01:48:16.40 |
+03:59:10.8 |
HIP 8329 |
14.16 |
| 2026-04-01 12:00 |
01:48:18.71 |
+03:59:26.9 |
HIP 8329 |
14.79 |
| 2026-04-02 00:00 |
01:48:21.03 |
+03:59:43.0 |
HIP 8329 |
15.42 |
| 2026-04-02 12:00 |
01:48:23.35 |
+03:59:59.1 |
HIP 8329 |
16.05 |
| 2026-04-03 00:00 |
01:48:25.68 |
+04:00:15.1 |
HIP 8329 |
16.69 |
| 2026-04-03 12:00 |
01:48:28.02 |
+04:00:31.2 |
HIP 8329 |
17.33 |
| 2026-04-04 00:00 |
01:48:30.36 |
+04:00:47.2 |
HIP 8329 |
17.97 |
| 2026-04-04 12:00 |
01:48:32.71 |
+04:01:03.2 |
HIP 8329 |
18.61 |
| 2026-04-05 00:00 |
01:48:35.06 |
+04:01:19.2 |
HIP 8329 |
19.25 |
| 2026-04-05 12:00 |
01:48:37.42 |
+04:01:35.2 |
HIP 8329 |
19.89 |
| 2026-04-06 00:00 |
01:48:39.78 |
+04:01:51.2 |
HIP 8329 |
20.53 |
| 2026-04-06 12:00 |
01:48:42.15 |
+04:02:07.2 |
HIP 8329 |
21.18 |
| 2026-04-07 00:00 |
01:48:44.52 |
+04:02:23.1 |
HIP 8404 |
21.76 |
| 2026-04-07 12:00 |
01:48:46.90 |
+04:02:39.0 |
HIP 8404 |
22.15 |
| 2026-04-08 00:00 |
01:48:49.28 |
+04:02:54.9 |
HIP 8404 |
22.55 |
| 2026-04-08 12:00 |
01:48:51.67 |
+04:03:10.8 |
HIP 8404 |
22.96 |
| 2026-04-09 00:00 |
01:48:54.05 |
+04:03:26.7 |
HIP 8404 |
23.39 |
| 2026-04-09 12:00 |
01:48:56.45 |
+04:03:42.5 |
HIP 8404 |
23.83 |
| 2026-04-10 00:00 |
01:48:58.84 |
+04:03:58.3 |
HIP 8404 |
24.27 |
| 2026-04-10 12:00 |
01:49:01.24 |
+04:04:14.1 |
HIP 8404 |
24.72 |
| 2026-04-11 00:00 |
01:49:03.65 |
+04:04:29.9 |
HIP 8404 |
25.19 |
| 2026-04-11 12:00 |
01:49:06.05 |
+04:04:45.6 |
HIP 8404 |
25.66 |
| 2026-04-12 00:00 |
01:49:08.46 |
+04:05:01.3 |
HIP 8404 |
26.14 |
| 2026-04-12 12:00 |
01:49:10.88 |
+04:05:17.0 |
HIP 8404 |
26.62 |
| 2026-04-13 00:00 |
01:49:13.29 |
+04:05:32.7 |
HIP 8404 |
27.12 |
| 2026-04-13 12:00 |
01:49:15.71 |
+04:05:48.3 |
HIP 8605 |
27.28 |
| 2026-04-14 00:00 |
01:49:18.13 |
+04:06:03.9 |
HIP 8605 |
26.63 |
| 2026-04-14 12:00 |
01:49:20.55 |
+04:06:19.4 |
HIP 8605 |
25.98 |
| 2026-04-15 00:00 |
01:49:22.97 |
+04:06:34.9 |
HIP 8605 |
25.33 |
| 2026-04-15 12:00 |
01:49:25.40 |
+04:06:50.4 |
HIP 8605 |
24.68 |
| 2026-04-16 00:00 |
01:49:27.82 |
+04:07:05.9 |
HIP 8605 |
24.03 |