| 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 |
0.950 |
| gb |
-0.999 |
| k |
1.000 |
| δ90 |
9.995 |
| 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) |
| 2026-09-20 00:00 |
12:06:53.21 |
-78:39:26.2 |
HIP 59093 |
5.07 |
| 2026-09-20 12:00 |
12:07:08.80 |
-78:39:30.3 |
HIP 59093 |
4.96 |
| 2026-09-21 00:00 |
12:07:24.40 |
-78:39:34.8 |
HIP 59093 |
4.97 |
| 2026-09-21 12:00 |
12:07:40.01 |
-78:39:39.6 |
HIP 59093 |
5.09 |
| 2026-09-22 00:00 |
12:07:55.62 |
-78:39:44.9 |
HIP 59093 |
5.31 |
| 2026-09-22 12:00 |
12:08:11.25 |
-78:39:50.5 |
HIP 59093 |
5.63 |
| 2026-09-23 00:00 |
12:08:26.88 |
-78:39:56.6 |
HIP 59093 |
6.02 |
| 2026-09-23 12:00 |
12:08:42.51 |
-78:40:03.0 |
HIP 59093 |
6.48 |
| 2026-09-24 00:00 |
12:08:58.15 |
-78:40:09.7 |
HIP 59243 |
6.73 |
| 2026-09-24 12:00 |
12:09:13.80 |
-78:40:16.9 |
HIP 59243 |
6.60 |
| 2026-09-25 00:00 |
12:09:29.45 |
-78:40:24.5 |
HIP 59243 |
6.56 |
| 2026-09-25 12:00 |
12:09:45.10 |
-78:40:32.4 |
HIP 59243 |
6.59 |
| 2026-09-26 00:00 |
12:10:00.76 |
-78:40:40.7 |
HIP 59243 |
6.72 |
| 2026-09-26 12:00 |
12:10:16.42 |
-78:40:49.4 |
HIP 59243 |
6.92 |
| 2026-09-27 00:00 |
12:10:32.08 |
-78:40:58.5 |
HIP 59243 |
7.20 |
| 2026-09-27 12:00 |
12:10:47.74 |
-78:41:08.0 |
HIP 59243 |
7.54 |
| 2026-09-28 00:00 |
12:11:03.40 |
-78:41:17.8 |
HIP 59243 |
7.94 |
| 2026-09-28 12:00 |
12:11:19.06 |
-78:41:28.1 |
HIP 59243 |
8.39 |
| 2026-09-29 00:00 |
12:11:34.72 |
-78:41:38.7 |
HIP 59243 |
8.88 |
| 2026-09-29 12:00 |
12:11:50.38 |
-78:41:49.6 |
HIP 59243 |
9.41 |
| 2026-09-30 00:00 |
12:12:06.04 |
-78:42:01.0 |
HIP 59647 |
9.33 |
| 2026-09-30 12:00 |
12:12:21.69 |
-78:42:12.8 |
HIP 59647 |
9.07 |
| 2026-10-01 00:00 |
12:12:37.34 |
-78:42:24.9 |
HIP 59647 |
8.88 |
| 2026-10-01 12:00 |
12:12:52.98 |
-78:42:37.4 |
HIP 59647 |
8.77 |
| 2026-10-02 00:00 |
12:13:08.63 |
-78:42:50.3 |
HIP 59647 |
8.73 |
| 2026-10-02 12:00 |
12:13:24.26 |
-78:43:03.5 |
HIP 59647 |
8.77 |
| 2026-10-03 00:00 |
12:13:39.89 |
-78:43:17.2 |
HIP 59647 |
8.89 |
| 2026-10-03 12:00 |
12:13:55.51 |
-78:43:31.2 |
HIP 59647 |
9.09 |
| 2026-10-04 00:00 |
12:14:11.13 |
-78:43:45.6 |
HIP 59647 |
9.35 |
| 2026-10-04 12:00 |
12:14:26.73 |
-78:44:00.3 |
HIP 59647 |
9.69 |
| 2026-10-05 00:00 |
12:14:42.33 |
-78:44:15.5 |
HIP 59647 |
10.08 |
| 2026-10-05 12:00 |
12:14:57.91 |
-78:44:31.0 |
HIP 59647 |
10.53 |
| 2026-10-06 00:00 |
12:15:13.49 |
-78:44:46.9 |
HIP 59647 |
11.02 |
| 2026-10-06 12:00 |
12:15:29.05 |
-78:45:03.2 |
HIP 59647 |
11.55 |
| 2026-10-07 00:00 |
12:15:44.61 |
-78:45:19.8 |
HIP 59647 |
12.12 |
| 2026-10-07 12:00 |
12:16:00.14 |
-78:45:36.8 |
HIP 59647 |
12.72 |
| 2026-10-08 00:00 |
12:16:15.67 |
-78:45:54.2 |
HIP 59647 |
13.35 |
| 2026-10-08 12:00 |
12:16:31.18 |
-78:46:12.0 |
HIP 59647 |
14.01 |
| 2026-10-09 00:00 |
12:16:46.67 |
-78:46:30.1 |
HIP 59647 |
14.68 |
| 2026-10-09 12:00 |
12:17:02.15 |
-78:46:48.7 |
HIP 59647 |
15.37 |
| 2026-10-10 00:00 |
12:17:17.61 |
-78:47:07.5 |
HIP 59647 |
16.08 |
| 2026-10-10 12:00 |
12:17:33.05 |
-78:47:26.8 |
HIP 59647 |
16.80 |
| 2026-10-11 00:00 |
12:17:48.47 |
-78:47:46.4 |
HIP 59647 |
17.53 |