C/1998 H1 (Stonehouse)
| Parameter |
Value |
| Designation |
C/1998 H1 (Stonehouse) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-04-14T10:13:23.263680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
407 |
| NEO |
- |
| M1 |
10.000 |
| K1 |
9.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-05-13.0000000 |
| e |
0.99794041 |
| q (au) |
1.487291 |
| a (au) |
722.129549 |
| i (deg) |
104.692960 |
| Ω (om, deg) |
222.109070 |
| ω (w, deg) |
1.325283 |
| M (ma, deg) |
0.001451 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.349 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.349 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
10.000 |
| 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 |
02:28:35.03 |
+33:12:23.0 |
HIP 11635 |
22.71 |
| 2026-02-03 12:00 |
02:28:35.24 |
+33:12:11.1 |
HIP 11635 |
22.78 |
| 2026-02-04 00:00 |
02:28:35.48 |
+33:11:59.3 |
HIP 11635 |
22.85 |
| 2026-02-04 12:00 |
02:28:35.73 |
+33:11:47.5 |
HIP 11635 |
22.91 |
| 2026-02-05 00:00 |
02:28:36.02 |
+33:11:35.9 |
HIP 11635 |
22.97 |
| 2026-02-05 12:00 |
02:28:36.32 |
+33:11:24.4 |
HIP 11635 |
23.02 |
| 2026-02-06 00:00 |
02:28:36.65 |
+33:11:13.0 |
HIP 11635 |
23.07 |
| 2026-02-06 12:00 |
02:28:37.00 |
+33:11:01.7 |
HIP 11635 |
23.12 |
| 2026-02-07 00:00 |
02:28:37.37 |
+33:10:50.5 |
HIP 11635 |
23.17 |
| 2026-02-07 12:00 |
02:28:37.77 |
+33:10:39.5 |
HIP 11635 |
23.21 |
| 2026-02-08 00:00 |
02:28:38.20 |
+33:10:28.5 |
HIP 11635 |
23.25 |
| 2026-02-08 12:00 |
02:28:38.64 |
+33:10:17.7 |
HIP 11635 |
23.28 |
| 2026-02-09 00:00 |
02:28:39.11 |
+33:10:06.9 |
HIP 11635 |
23.31 |
| 2026-02-09 12:00 |
02:28:39.60 |
+33:09:56.3 |
HIP 11635 |
23.34 |
| 2026-02-10 00:00 |
02:28:40.12 |
+33:09:45.8 |
HIP 11635 |
23.37 |
| 2026-02-10 12:00 |
02:28:40.65 |
+33:09:35.4 |
HIP 11635 |
23.39 |
| 2026-02-11 00:00 |
02:28:41.21 |
+33:09:25.2 |
HIP 11635 |
23.41 |
| 2026-02-11 12:00 |
02:28:41.80 |
+33:09:15.0 |
HIP 11635 |
23.42 |
| 2026-02-12 00:00 |
02:28:42.41 |
+33:09:05.0 |
HIP 11635 |
23.43 |
| 2026-02-12 12:00 |
02:28:43.04 |
+33:08:55.1 |
HIP 11635 |
23.44 |
| 2026-02-13 00:00 |
02:28:43.69 |
+33:08:45.3 |
HIP 11635 |
23.45 |
| 2026-02-13 12:00 |
02:28:44.36 |
+33:08:35.7 |
HIP 11635 |
23.45 |
| 2026-02-14 00:00 |
02:28:45.06 |
+33:08:26.1 |
HIP 11635 |
23.45 |
| 2026-02-14 12:00 |
02:28:45.78 |
+33:08:16.7 |
HIP 11635 |
23.45 |
| 2026-02-15 00:00 |
02:28:46.53 |
+33:08:07.4 |
HIP 11635 |
23.45 |
| 2026-02-15 12:00 |
02:28:47.29 |
+33:07:58.2 |
HIP 11635 |
23.44 |
| 2026-02-16 00:00 |
02:28:48.08 |
+33:07:49.1 |
HIP 11635 |
23.43 |
| 2026-02-16 12:00 |
02:28:48.89 |
+33:07:40.2 |
HIP 11635 |
23.41 |
| 2026-02-17 00:00 |
02:28:49.73 |
+33:07:31.4 |
HIP 11635 |
23.40 |
| 2026-02-17 12:00 |
02:28:50.58 |
+33:07:22.7 |
HIP 11635 |
23.38 |
| 2026-02-18 00:00 |
02:28:51.46 |
+33:07:14.2 |
HIP 11635 |
23.36 |
| 2026-02-18 12:00 |
02:28:52.36 |
+33:07:05.7 |
HIP 11635 |
23.34 |
| 2026-02-19 00:00 |
02:28:53.28 |
+33:06:57.4 |
HIP 11635 |
23.31 |
| 2026-02-19 12:00 |
02:28:54.23 |
+33:06:49.2 |
HIP 11635 |
23.28 |
| 2026-02-20 00:00 |
02:28:55.19 |
+33:06:41.2 |
HIP 11635 |
23.25 |
| 2026-02-20 12:00 |
02:28:56.18 |
+33:06:33.2 |
HIP 11635 |
23.22 |
| 2026-02-21 00:00 |
02:28:57.19 |
+33:06:25.4 |
HIP 11635 |
23.19 |
| 2026-02-21 12:00 |
02:28:58.22 |
+33:06:17.8 |
HIP 11635 |
23.15 |
| 2026-02-22 00:00 |
02:28:59.27 |
+33:06:10.2 |
HIP 11635 |
23.11 |
| 2026-02-22 12:00 |
02:29:00.34 |
+33:06:02.8 |
HIP 11635 |
23.08 |
| 2026-02-23 00:00 |
02:29:01.44 |
+33:05:55.5 |
HIP 11635 |
23.03 |
| 2026-02-23 12:00 |
02:29:02.55 |
+33:05:48.3 |
HIP 11635 |
22.99 |
| 2026-02-24 00:00 |
02:29:03.69 |
+33:05:41.3 |
HIP 11635 |
22.95 |