C/1997 H2 (SOHO)
| Parameter |
Value |
| Designation |
C/1997 H2 (SOHO) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1997-05-03T04:04:48Z |
| Orbit solution date (soln_date, UTC) |
- |
| Obs used |
115 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1997-05-03.1700000 |
| e |
1.00000000 |
| q (au) |
0.136100 |
| a (au) |
- |
| i (deg) |
18.320000 |
| Ω (om, deg) |
225.820000 |
| ω (w, deg) |
201.470000 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-02-03 00:00 |
16:02:35.53 |
-15:46:34.3 |
HIP 78430 |
34.83 |
| 2026-02-03 12:00 |
16:02:36.30 |
-15:46:33.6 |
HIP 78430 |
34.96 |
| 2026-02-04 00:00 |
16:02:37.06 |
-15:46:32.9 |
HIP 78430 |
35.10 |
| 2026-02-04 12:00 |
16:02:37.79 |
-15:46:32.1 |
HIP 78430 |
35.23 |
| 2026-02-05 00:00 |
16:02:38.50 |
-15:46:31.3 |
HIP 78430 |
35.36 |
| 2026-02-05 12:00 |
16:02:39.20 |
-15:46:30.4 |
HIP 78430 |
35.48 |
| 2026-02-06 00:00 |
16:02:39.88 |
-15:46:29.4 |
HIP 78430 |
35.60 |
| 2026-02-06 12:00 |
16:02:40.54 |
-15:46:28.4 |
HIP 78430 |
35.71 |
| 2026-02-07 00:00 |
16:02:41.17 |
-15:46:27.3 |
HIP 78430 |
35.82 |
| 2026-02-07 12:00 |
16:02:41.79 |
-15:46:26.1 |
HIP 78430 |
35.93 |
| 2026-02-08 00:00 |
16:02:42.39 |
-15:46:24.9 |
HIP 78430 |
36.03 |
| 2026-02-08 12:00 |
16:02:42.97 |
-15:46:23.7 |
HIP 78430 |
36.13 |
| 2026-02-09 00:00 |
16:02:43.53 |
-15:46:22.3 |
HIP 78430 |
36.23 |
| 2026-02-09 12:00 |
16:02:44.08 |
-15:46:20.9 |
HIP 78430 |
36.32 |
| 2026-02-10 00:00 |
16:02:44.60 |
-15:46:19.4 |
HIP 78430 |
36.41 |
| 2026-02-10 12:00 |
16:02:45.10 |
-15:46:17.9 |
HIP 78430 |
36.49 |
| 2026-02-11 00:00 |
16:02:45.58 |
-15:46:16.3 |
HIP 78430 |
36.57 |
| 2026-02-11 12:00 |
16:02:46.05 |
-15:46:14.7 |
HIP 78430 |
36.64 |
| 2026-02-12 00:00 |
16:02:46.49 |
-15:46:13.0 |
HIP 78430 |
36.71 |
| 2026-02-12 12:00 |
16:02:46.92 |
-15:46:11.2 |
HIP 78430 |
36.78 |
| 2026-02-13 00:00 |
16:02:47.32 |
-15:46:09.4 |
HIP 78430 |
36.84 |
| 2026-02-13 12:00 |
16:02:47.70 |
-15:46:07.5 |
HIP 78430 |
36.89 |
| 2026-02-14 00:00 |
16:02:48.07 |
-15:46:05.5 |
HIP 78430 |
36.95 |
| 2026-02-14 12:00 |
16:02:48.41 |
-15:46:03.5 |
HIP 78430 |
37.00 |
| 2026-02-15 00:00 |
16:02:48.74 |
-15:46:01.4 |
HIP 78430 |
37.04 |
| 2026-02-15 12:00 |
16:02:49.04 |
-15:45:59.3 |
HIP 78430 |
37.08 |
| 2026-02-16 00:00 |
16:02:49.33 |
-15:45:57.1 |
HIP 78503 |
37.09 |
| 2026-02-16 12:00 |
16:02:49.59 |
-15:45:54.8 |
HIP 78503 |
37.09 |
| 2026-02-17 00:00 |
16:02:49.84 |
-15:45:52.5 |
HIP 78503 |
37.08 |
| 2026-02-17 12:00 |
16:02:50.06 |
-15:45:50.1 |
HIP 78503 |
37.07 |
| 2026-02-18 00:00 |
16:02:50.26 |
-15:45:47.6 |
HIP 78503 |
37.06 |
| 2026-02-18 12:00 |
16:02:50.45 |
-15:45:45.1 |
HIP 78503 |
37.04 |
| 2026-02-19 00:00 |
16:02:50.61 |
-15:45:42.6 |
HIP 78503 |
37.03 |
| 2026-02-19 12:00 |
16:02:50.76 |
-15:45:40.0 |
HIP 78503 |
37.01 |
| 2026-02-20 00:00 |
16:02:50.88 |
-15:45:37.3 |
HIP 78503 |
36.98 |
| 2026-02-20 12:00 |
16:02:50.98 |
-15:45:34.5 |
HIP 78503 |
36.95 |
| 2026-02-21 00:00 |
16:02:51.07 |
-15:45:31.7 |
HIP 78503 |
36.92 |
| 2026-02-21 12:00 |
16:02:51.13 |
-15:45:28.9 |
HIP 78503 |
36.89 |
| 2026-02-22 00:00 |
16:02:51.17 |
-15:45:26.0 |
HIP 78503 |
36.85 |
| 2026-02-22 12:00 |
16:02:51.20 |
-15:45:23.0 |
HIP 78503 |
36.81 |
| 2026-02-23 00:00 |
16:02:51.20 |
-15:45:19.9 |
HIP 78503 |
36.77 |
| 2026-02-23 12:00 |
16:02:51.18 |
-15:45:16.9 |
HIP 78503 |
36.72 |
| 2026-02-24 00:00 |
16:02:51.14 |
-15:45:13.7 |
HIP 78503 |
36.67 |