| Parameter |
Value |
| Designation |
C/2008 H1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-03-16T10:10:14.488320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:18Z |
| Obs used |
252 |
| NEO |
- |
| M1 |
13.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-05-16.0000000 |
| e |
0.94658786 |
| q (au) |
2.760294 |
| a (au) |
51.679144 |
| i (deg) |
75.492175 |
| Ω (om, deg) |
34.630430 |
| ω (w, deg) |
96.043511 |
| M (ma, deg) |
0.160706 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.423 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.423 |
| n |
2.000 |
| gf |
0.983 |
| gb |
-0.505 |
| k |
1.000 |
| δ90 |
9.932 |
| 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 |
11:42:37.04 |
-81:06:11.9 |
HIP 58032 |
27.07 |
| 2026-05-12 12:00 |
11:42:24.03 |
-81:05:29.6 |
HIP 58032 |
27.72 |
| 2026-05-13 00:00 |
11:42:11.21 |
-81:04:47.0 |
HIP 58032 |
28.38 |
| 2026-05-13 12:00 |
11:41:58.56 |
-81:04:04.1 |
HIP 58032 |
29.05 |
| 2026-05-14 00:00 |
11:41:46.11 |
-81:03:20.9 |
HIP 58032 |
29.72 |
| 2026-05-14 12:00 |
11:41:33.84 |
-81:02:37.6 |
HIP 58032 |
30.39 |
| 2026-05-15 00:00 |
11:41:21.75 |
-81:01:53.9 |
HIP 58032 |
31.07 |
| 2026-05-15 12:00 |
11:41:09.85 |
-81:01:10.1 |
HIP 58032 |
31.76 |
| 2026-05-16 00:00 |
11:40:58.14 |
-81:00:25.9 |
HIP 57192 |
32.07 |
| 2026-05-16 12:00 |
11:40:46.62 |
-80:59:41.6 |
HIP 57192 |
31.44 |
| 2026-05-17 00:00 |
11:40:35.28 |
-80:58:57.1 |
HIP 57192 |
30.82 |
| 2026-05-17 12:00 |
11:40:24.14 |
-80:58:12.3 |
HIP 57192 |
30.21 |
| 2026-05-18 00:00 |
11:40:13.18 |
-80:57:27.3 |
HIP 57192 |
29.61 |
| 2026-05-18 12:00 |
11:40:02.40 |
-80:56:42.1 |
HIP 57192 |
29.01 |
| 2026-05-19 00:00 |
11:39:51.82 |
-80:55:56.7 |
HIP 57192 |
28.43 |
| 2026-05-19 12:00 |
11:39:41.43 |
-80:55:11.1 |
HIP 57192 |
27.85 |
| 2026-05-20 00:00 |
11:39:31.22 |
-80:54:25.3 |
HIP 57192 |
27.29 |
| 2026-05-20 12:00 |
11:39:21.20 |
-80:53:39.3 |
HIP 57192 |
26.73 |
| 2026-05-21 00:00 |
11:39:11.37 |
-80:52:53.1 |
HIP 57192 |
26.19 |
| 2026-05-21 12:00 |
11:39:01.73 |
-80:52:06.7 |
HIP 57192 |
25.65 |
| 2026-05-22 00:00 |
11:38:52.28 |
-80:51:20.2 |
HIP 57192 |
25.13 |
| 2026-05-22 12:00 |
11:38:43.01 |
-80:50:33.5 |
HIP 57192 |
24.63 |
| 2026-05-23 00:00 |
11:38:33.93 |
-80:49:46.6 |
HIP 57192 |
24.14 |
| 2026-05-23 12:00 |
11:38:25.04 |
-80:48:59.6 |
HIP 57192 |
23.66 |
| 2026-05-24 00:00 |
11:38:16.34 |
-80:48:12.4 |
HIP 57192 |
23.20 |
| 2026-05-24 12:00 |
11:38:07.83 |
-80:47:25.1 |
HIP 57192 |
22.76 |
| 2026-05-25 00:00 |
11:37:59.50 |
-80:46:37.6 |
HIP 57192 |
22.34 |
| 2026-05-25 12:00 |
11:37:51.35 |
-80:45:49.9 |
HIP 57192 |
21.94 |
| 2026-05-26 00:00 |
11:37:43.40 |
-80:45:02.2 |
HIP 57192 |
21.56 |
| 2026-05-26 12:00 |
11:37:35.63 |
-80:44:14.2 |
HIP 57192 |
21.19 |
| 2026-05-27 00:00 |
11:37:28.04 |
-80:43:26.2 |
HIP 57192 |
20.86 |
| 2026-05-27 12:00 |
11:37:20.64 |
-80:42:38.1 |
HIP 57192 |
20.54 |
| 2026-05-28 00:00 |
11:37:13.42 |
-80:41:49.8 |
HIP 57192 |
20.25 |
| 2026-05-28 12:00 |
11:37:06.39 |
-80:41:01.4 |
HIP 57192 |
19.99 |
| 2026-05-29 00:00 |
11:36:59.54 |
-80:40:12.9 |
HIP 57192 |
19.76 |
| 2026-05-29 12:00 |
11:36:52.88 |
-80:39:24.2 |
HIP 57192 |
19.55 |
| 2026-05-30 00:00 |
11:36:46.40 |
-80:38:35.5 |
HIP 57192 |
19.37 |
| 2026-05-30 12:00 |
11:36:40.10 |
-80:37:46.7 |
HIP 57192 |
19.22 |
| 2026-05-31 00:00 |
11:36:33.98 |
-80:36:57.8 |
HIP 57192 |
19.10 |
| 2026-05-31 12:00 |
11:36:28.05 |
-80:36:08.7 |
HIP 57192 |
19.01 |
| 2026-06-01 00:00 |
11:36:22.30 |
-80:35:19.6 |
HIP 57192 |
18.95 |
| 2026-06-01 12:00 |
11:36:16.72 |
-80:34:30.5 |
HIP 57192 |
18.93 |
| 2026-06-02 00:00 |
11:36:11.33 |
-80:33:41.2 |
HIP 57192 |
18.93 |