| Parameter |
Value |
| Designation |
C/2003 H2 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2003-05-17T23:15:08.225280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:29Z |
| Obs used |
189 |
| NEO |
- |
| M1 |
14.200 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-05-22.0000000 |
| e |
0.94291012 |
| q (au) |
2.178516 |
| a (au) |
38.159402 |
| i (deg) |
74.217540 |
| Ω (om, deg) |
79.838018 |
| ω (w, deg) |
155.082163 |
| M (ma, deg) |
0.016855 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.725 + 2.527\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.725 |
| n |
2.527 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.999 |
| 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) |
| 2026-05-12 00:00 |
04:39:18.45 |
-19:51:29.5 |
HIP 21722 |
14.43 |
| 2026-05-12 12:00 |
04:39:21.49 |
-19:51:11.9 |
HIP 21722 |
14.35 |
| 2026-05-13 00:00 |
04:39:24.55 |
-19:50:54.4 |
HIP 21722 |
14.31 |
| 2026-05-13 12:00 |
04:39:27.61 |
-19:50:37.2 |
HIP 21722 |
14.30 |
| 2026-05-14 00:00 |
04:39:30.68 |
-19:50:20.2 |
HIP 21722 |
14.33 |
| 2026-05-14 12:00 |
04:39:33.76 |
-19:50:03.4 |
HIP 21722 |
14.40 |
| 2026-05-15 00:00 |
04:39:36.84 |
-19:49:46.9 |
HIP 21722 |
14.51 |
| 2026-05-15 12:00 |
04:39:39.94 |
-19:49:30.6 |
HIP 21763 |
14.33 |
| 2026-05-16 00:00 |
04:39:43.04 |
-19:49:14.5 |
HIP 21763 |
13.60 |
| 2026-05-16 12:00 |
04:39:46.15 |
-19:48:58.7 |
HIP 21763 |
12.88 |
| 2026-05-17 00:00 |
04:39:49.26 |
-19:48:43.1 |
HIP 21763 |
12.17 |
| 2026-05-17 12:00 |
04:39:52.38 |
-19:48:27.8 |
HIP 21763 |
11.47 |
| 2026-05-18 00:00 |
04:39:55.51 |
-19:48:12.7 |
HIP 21763 |
10.78 |
| 2026-05-18 12:00 |
04:39:58.65 |
-19:47:57.8 |
HIP 21763 |
10.10 |
| 2026-05-19 00:00 |
04:40:01.79 |
-19:47:43.2 |
HIP 21763 |
9.45 |
| 2026-05-19 12:00 |
04:40:04.94 |
-19:47:28.9 |
HIP 21763 |
8.81 |
| 2026-05-20 00:00 |
04:40:08.09 |
-19:47:14.7 |
HIP 21763 |
8.21 |
| 2026-05-20 12:00 |
04:40:11.25 |
-19:47:00.8 |
HIP 21763 |
7.63 |
| 2026-05-21 00:00 |
04:40:14.42 |
-19:46:47.2 |
HIP 21763 |
7.10 |
| 2026-05-21 12:00 |
04:40:17.59 |
-19:46:33.8 |
HIP 21763 |
6.63 |
| 2026-05-22 00:00 |
04:40:20.76 |
-19:46:20.7 |
HIP 21763 |
6.22 |
| 2026-05-22 12:00 |
04:40:23.94 |
-19:46:07.8 |
HIP 21763 |
5.88 |
| 2026-05-23 00:00 |
04:40:27.12 |
-19:45:55.1 |
HIP 21763 |
5.64 |
| 2026-05-23 12:00 |
04:40:30.31 |
-19:45:42.7 |
HIP 21763 |
5.51 |
| 2026-05-24 00:00 |
04:40:33.50 |
-19:45:30.5 |
HIP 21763 |
5.49 |
| 2026-05-24 12:00 |
04:40:36.70 |
-19:45:18.6 |
HIP 21763 |
5.58 |
| 2026-05-25 00:00 |
04:40:39.90 |
-19:45:06.9 |
HIP 21763 |
5.78 |
| 2026-05-25 12:00 |
04:40:43.10 |
-19:44:55.5 |
HIP 21763 |
6.07 |
| 2026-05-26 00:00 |
04:40:46.30 |
-19:44:44.3 |
HIP 21763 |
6.45 |
| 2026-05-26 12:00 |
04:40:49.51 |
-19:44:33.4 |
HIP 21763 |
6.91 |
| 2026-05-27 00:00 |
04:40:52.72 |
-19:44:22.7 |
HIP 21763 |
7.41 |
| 2026-05-27 12:00 |
04:40:55.94 |
-19:44:12.3 |
HIP 21763 |
7.97 |
| 2026-05-28 00:00 |
04:40:59.15 |
-19:44:02.1 |
HIP 21763 |
8.56 |
| 2026-05-28 12:00 |
04:41:02.37 |
-19:43:52.2 |
HIP 21763 |
9.18 |
| 2026-05-29 00:00 |
04:41:05.59 |
-19:43:42.5 |
HIP 21763 |
9.82 |
| 2026-05-29 12:00 |
04:41:08.81 |
-19:43:33.1 |
HIP 21763 |
10.49 |
| 2026-05-30 00:00 |
04:41:12.04 |
-19:43:23.9 |
HIP 21763 |
11.17 |
| 2026-05-30 12:00 |
04:41:15.26 |
-19:43:15.0 |
HIP 21763 |
11.86 |
| 2026-05-31 00:00 |
04:41:18.49 |
-19:43:06.3 |
HIP 21763 |
12.56 |
| 2026-05-31 12:00 |
04:41:21.71 |
-19:42:57.9 |
HIP 21763 |
13.27 |
| 2026-06-01 00:00 |
04:41:24.94 |
-19:42:49.7 |
HIP 21763 |
13.99 |
| 2026-06-01 12:00 |
04:41:28.17 |
-19:42:41.8 |
HIP 21763 |
14.72 |
| 2026-06-02 00:00 |
04:41:31.40 |
-19:42:34.2 |
HIP 21763 |
15.45 |