| 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) |
| 2026-03-26 00:00 |
12:13:52.62 |
-81:43:38.1 |
HIP 60573 |
24.60 |
| 2026-03-26 12:00 |
12:13:28.70 |
-81:43:36.9 |
HIP 60573 |
25.44 |
| 2026-03-27 00:00 |
12:13:04.79 |
-81:43:35.1 |
HIP 60573 |
26.28 |
| 2026-03-27 12:00 |
12:12:40.89 |
-81:43:32.8 |
HIP 60573 |
27.13 |
| 2026-03-28 00:00 |
12:12:17.00 |
-81:43:29.9 |
HIP 60573 |
27.97 |
| 2026-03-28 12:00 |
12:11:53.13 |
-81:43:26.5 |
HIP 60573 |
28.81 |
| 2026-03-29 00:00 |
12:11:29.27 |
-81:43:22.5 |
HIP 60573 |
29.65 |
| 2026-03-29 12:00 |
12:11:05.44 |
-81:43:18.0 |
HIP 60573 |
30.49 |
| 2026-03-30 00:00 |
12:10:41.63 |
-81:43:12.9 |
HIP 60573 |
31.34 |
| 2026-03-30 12:00 |
12:10:17.85 |
-81:43:07.3 |
HIP 60573 |
32.18 |
| 2026-03-31 00:00 |
12:09:54.10 |
-81:43:01.2 |
HIP 60573 |
33.02 |
| 2026-03-31 12:00 |
12:09:30.39 |
-81:42:54.5 |
HIP 59722 |
33.47 |
| 2026-04-01 00:00 |
12:09:06.71 |
-81:42:47.3 |
HIP 59722 |
33.68 |
| 2026-04-01 12:00 |
12:08:43.06 |
-81:42:39.5 |
HIP 58911 |
33.65 |
| 2026-04-02 00:00 |
12:08:19.46 |
-81:42:31.3 |
HIP 58911 |
33.59 |
| 2026-04-02 12:00 |
12:07:55.91 |
-81:42:22.4 |
HIP 58911 |
33.57 |
| 2026-04-03 00:00 |
12:07:32.40 |
-81:42:13.1 |
HIP 58911 |
33.57 |
| 2026-04-03 12:00 |
12:07:08.94 |
-81:42:03.2 |
HIP 58911 |
33.61 |
| 2026-04-04 00:00 |
12:06:45.53 |
-81:41:52.8 |
HIP 58104 |
33.37 |
| 2026-04-04 12:00 |
12:06:22.18 |
-81:41:41.9 |
HIP 58104 |
32.59 |
| 2026-04-05 00:00 |
12:05:58.89 |
-81:41:30.4 |
HIP 58104 |
31.82 |
| 2026-04-05 12:00 |
12:05:35.65 |
-81:41:18.4 |
HIP 58104 |
31.04 |
| 2026-04-06 00:00 |
12:05:12.48 |
-81:41:05.9 |
HIP 58104 |
30.26 |
| 2026-04-06 12:00 |
12:04:49.38 |
-81:40:52.9 |
HIP 58104 |
29.49 |
| 2026-04-07 00:00 |
12:04:26.34 |
-81:40:39.3 |
HIP 58104 |
28.72 |
| 2026-04-07 12:00 |
12:04:03.38 |
-81:40:25.3 |
HIP 58104 |
27.95 |
| 2026-04-08 00:00 |
12:03:40.49 |
-81:40:10.7 |
HIP 58104 |
27.18 |
| 2026-04-08 12:00 |
12:03:17.67 |
-81:39:55.6 |
HIP 58104 |
26.41 |
| 2026-04-09 00:00 |
12:02:54.94 |
-81:39:40.0 |
HIP 58104 |
25.65 |
| 2026-04-09 12:00 |
12:02:32.28 |
-81:39:23.9 |
HIP 58104 |
24.89 |
| 2026-04-10 00:00 |
12:02:09.72 |
-81:39:07.2 |
HIP 58104 |
24.13 |
| 2026-04-10 12:00 |
12:01:47.23 |
-81:38:50.1 |
HIP 58104 |
23.38 |
| 2026-04-11 00:00 |
12:01:24.84 |
-81:38:32.5 |
HIP 58104 |
22.63 |
| 2026-04-11 12:00 |
12:01:02.54 |
-81:38:14.3 |
HIP 58104 |
21.88 |
| 2026-04-12 00:00 |
12:00:40.33 |
-81:37:55.7 |
HIP 58104 |
21.14 |
| 2026-04-12 12:00 |
12:00:18.22 |
-81:37:36.6 |
HIP 58104 |
20.41 |
| 2026-04-13 00:00 |
11:59:56.21 |
-81:37:17.0 |
HIP 58104 |
19.68 |
| 2026-04-13 12:00 |
11:59:34.30 |
-81:36:56.8 |
HIP 58104 |
18.96 |
| 2026-04-14 00:00 |
11:59:12.50 |
-81:36:36.2 |
HIP 58104 |
18.24 |
| 2026-04-14 12:00 |
11:58:50.80 |
-81:36:15.1 |
HIP 58104 |
17.54 |
| 2026-04-15 00:00 |
11:58:29.21 |
-81:35:53.6 |
HIP 58104 |
16.84 |
| 2026-04-15 12:00 |
11:58:07.73 |
-81:35:31.5 |
HIP 58104 |
16.16 |
| 2026-04-16 00:00 |
11:57:46.37 |
-81:35:09.0 |
HIP 58104 |
15.49 |