| Parameter |
Value |
| Designation |
C/2005 H1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-10-28T12:40:07.613760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:48Z |
| Obs used |
169 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-05-28.0000000 |
| e |
0.89692366 |
| q (au) |
4.768597 |
| a (au) |
46.262766 |
| i (deg) |
81.512268 |
| Ω (om, deg) |
71.490714 |
| ω (w, deg) |
95.212944 |
| M (ma, deg) |
0.662384 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.636 + 5.458\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.636 |
| n |
5.458 |
| gf |
0.968 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.772 |
| 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) |
| 2026-03-26 00:00 |
17:52:50.75 |
-83:37:55.9 |
HIP 87931 |
25.25 |
| 2026-03-26 12:00 |
17:52:48.22 |
-83:38:44.6 |
HIP 87931 |
26.03 |
| 2026-03-27 00:00 |
17:52:45.41 |
-83:39:33.3 |
HIP 87931 |
26.82 |
| 2026-03-27 12:00 |
17:52:42.32 |
-83:40:21.9 |
HIP 87414 |
26.34 |
| 2026-03-28 00:00 |
17:52:38.96 |
-83:41:10.5 |
HIP 87414 |
25.52 |
| 2026-03-28 12:00 |
17:52:35.31 |
-83:41:59.1 |
HIP 87414 |
24.71 |
| 2026-03-29 00:00 |
17:52:31.38 |
-83:42:47.5 |
HIP 87414 |
23.90 |
| 2026-03-29 12:00 |
17:52:27.17 |
-83:43:35.9 |
HIP 87414 |
23.09 |
| 2026-03-30 00:00 |
17:52:22.68 |
-83:44:24.3 |
HIP 87414 |
22.28 |
| 2026-03-30 12:00 |
17:52:17.89 |
-83:45:12.5 |
HIP 87414 |
21.47 |
| 2026-03-31 00:00 |
17:52:12.82 |
-83:46:00.7 |
HIP 87414 |
20.66 |
| 2026-03-31 12:00 |
17:52:07.46 |
-83:46:48.9 |
HIP 87414 |
19.86 |
| 2026-04-01 00:00 |
17:52:01.81 |
-83:47:36.9 |
HIP 87414 |
19.05 |
| 2026-04-01 12:00 |
17:51:55.87 |
-83:48:24.9 |
HIP 87414 |
18.25 |
| 2026-04-02 00:00 |
17:51:49.64 |
-83:49:12.7 |
HIP 87414 |
17.46 |
| 2026-04-02 12:00 |
17:51:43.11 |
-83:50:00.5 |
HIP 87414 |
16.66 |
| 2026-04-03 00:00 |
17:51:36.29 |
-83:50:48.2 |
HIP 87414 |
15.87 |
| 2026-04-03 12:00 |
17:51:29.18 |
-83:51:35.8 |
HIP 87414 |
15.08 |
| 2026-04-04 00:00 |
17:51:21.76 |
-83:52:23.2 |
HIP 87414 |
14.30 |
| 2026-04-04 12:00 |
17:51:14.05 |
-83:53:10.6 |
HIP 87414 |
13.53 |
| 2026-04-05 00:00 |
17:51:06.03 |
-83:53:57.9 |
HIP 87414 |
12.76 |
| 2026-04-05 12:00 |
17:50:57.71 |
-83:54:45.0 |
HIP 87414 |
12.00 |
| 2026-04-06 00:00 |
17:50:49.10 |
-83:55:32.0 |
HIP 87414 |
11.25 |
| 2026-04-06 12:00 |
17:50:40.17 |
-83:56:18.9 |
HIP 87414 |
10.52 |
| 2026-04-07 00:00 |
17:50:30.95 |
-83:57:05.7 |
HIP 87414 |
9.80 |
| 2026-04-07 12:00 |
17:50:21.41 |
-83:57:52.4 |
HIP 87414 |
9.10 |
| 2026-04-08 00:00 |
17:50:11.57 |
-83:58:38.9 |
HIP 87414 |
8.43 |
| 2026-04-08 12:00 |
17:50:01.43 |
-83:59:25.3 |
HIP 87414 |
7.79 |
| 2026-04-09 00:00 |
17:49:50.97 |
-84:00:11.5 |
HIP 87414 |
7.19 |
| 2026-04-09 12:00 |
17:49:40.20 |
-84:00:57.6 |
HIP 87414 |
6.64 |
| 2026-04-10 00:00 |
17:49:29.12 |
-84:01:43.5 |
HIP 87414 |
6.16 |
| 2026-04-10 12:00 |
17:49:17.73 |
-84:02:29.3 |
HIP 87414 |
5.77 |
| 2026-04-11 00:00 |
17:49:06.02 |
-84:03:14.9 |
HIP 87414 |
5.47 |
| 2026-04-11 12:00 |
17:48:54.01 |
-84:04:00.4 |
HIP 87414 |
5.29 |
| 2026-04-12 00:00 |
17:48:41.67 |
-84:04:45.7 |
HIP 87414 |
5.25 |
| 2026-04-12 12:00 |
17:48:29.02 |
-84:05:30.8 |
HIP 87414 |
5.34 |
| 2026-04-13 00:00 |
17:48:16.06 |
-84:06:15.8 |
HIP 87414 |
5.55 |
| 2026-04-13 12:00 |
17:48:02.77 |
-84:07:00.5 |
HIP 87414 |
5.88 |
| 2026-04-14 00:00 |
17:47:49.17 |
-84:07:45.1 |
HIP 87414 |
6.31 |
| 2026-04-14 12:00 |
17:47:35.25 |
-84:08:29.5 |
HIP 87414 |
6.81 |
| 2026-04-15 00:00 |
17:47:21.01 |
-84:09:13.7 |
HIP 87414 |
7.38 |
| 2026-04-15 12:00 |
17:47:06.45 |
-84:09:57.7 |
HIP 87414 |
7.99 |
| 2026-04-16 00:00 |
17:46:51.57 |
-84:10:41.5 |
HIP 87414 |
8.65 |