| 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) |
| 2026-05-12 00:00 |
02:34:40.87 |
+33:12:20.4 |
HIP 12043 |
21.70 |
| 2026-05-12 12:00 |
02:34:43.45 |
+33:12:31.0 |
HIP 12043 |
21.70 |
| 2026-05-13 00:00 |
02:34:46.04 |
+33:12:41.7 |
HIP 12043 |
21.71 |
| 2026-05-13 12:00 |
02:34:48.61 |
+33:12:52.5 |
HIP 12043 |
21.74 |
| 2026-05-14 00:00 |
02:34:51.19 |
+33:13:03.4 |
HIP 12043 |
21.79 |
| 2026-05-14 12:00 |
02:34:53.76 |
+33:13:14.3 |
HIP 12043 |
21.85 |
| 2026-05-15 00:00 |
02:34:56.32 |
+33:13:25.2 |
HIP 12043 |
21.93 |
| 2026-05-15 12:00 |
02:34:58.88 |
+33:13:36.3 |
HIP 12043 |
22.02 |
| 2026-05-16 00:00 |
02:35:01.44 |
+33:13:47.4 |
HIP 12043 |
22.13 |
| 2026-05-16 12:00 |
02:35:03.99 |
+33:13:58.5 |
HIP 12043 |
22.25 |
| 2026-05-17 00:00 |
02:35:06.53 |
+33:14:09.8 |
HIP 12043 |
22.39 |
| 2026-05-17 12:00 |
02:35:09.07 |
+33:14:21.1 |
HIP 12043 |
22.54 |
| 2026-05-18 00:00 |
02:35:11.61 |
+33:14:32.4 |
HIP 12043 |
22.71 |
| 2026-05-18 12:00 |
02:35:14.13 |
+33:14:43.9 |
HIP 12043 |
22.89 |
| 2026-05-19 00:00 |
02:35:16.66 |
+33:14:55.3 |
HIP 12043 |
23.08 |
| 2026-05-19 12:00 |
02:35:19.17 |
+33:15:06.9 |
HIP 12043 |
23.29 |
| 2026-05-20 00:00 |
02:35:21.68 |
+33:15:18.5 |
HIP 12043 |
23.51 |
| 2026-05-20 12:00 |
02:35:24.18 |
+33:15:30.1 |
HIP 12043 |
23.74 |
| 2026-05-21 00:00 |
02:35:26.68 |
+33:15:41.9 |
HIP 12043 |
23.98 |
| 2026-05-21 12:00 |
02:35:29.17 |
+33:15:53.6 |
HIP 12043 |
24.24 |
| 2026-05-22 00:00 |
02:35:31.65 |
+33:16:05.4 |
HIP 12043 |
24.50 |
| 2026-05-22 12:00 |
02:35:34.12 |
+33:16:17.3 |
HIP 12043 |
24.78 |
| 2026-05-23 00:00 |
02:35:36.59 |
+33:16:29.2 |
HIP 12043 |
25.06 |
| 2026-05-23 12:00 |
02:35:39.05 |
+33:16:41.2 |
HIP 12043 |
25.36 |
| 2026-05-24 00:00 |
02:35:41.50 |
+33:16:53.3 |
HIP 12043 |
25.66 |
| 2026-05-24 12:00 |
02:35:43.95 |
+33:17:05.3 |
HIP 12043 |
25.97 |
| 2026-05-25 00:00 |
02:35:46.38 |
+33:17:17.5 |
HIP 12043 |
26.29 |
| 2026-05-25 12:00 |
02:35:48.81 |
+33:17:29.7 |
HIP 12043 |
26.62 |
| 2026-05-26 00:00 |
02:35:51.23 |
+33:17:41.9 |
HIP 12043 |
26.96 |
| 2026-05-26 12:00 |
02:35:53.64 |
+33:17:54.2 |
HIP 12043 |
27.30 |
| 2026-05-27 00:00 |
02:35:56.04 |
+33:18:06.5 |
HIP 12043 |
27.65 |
| 2026-05-27 12:00 |
02:35:58.43 |
+33:18:18.8 |
HIP 12043 |
28.00 |
| 2026-05-28 00:00 |
02:36:00.82 |
+33:18:31.2 |
HIP 12043 |
28.36 |
| 2026-05-28 12:00 |
02:36:03.19 |
+33:18:43.7 |
HIP 12200 |
28.54 |
| 2026-05-29 00:00 |
02:36:05.56 |
+33:18:56.2 |
HIP 12200 |
28.49 |
| 2026-05-29 12:00 |
02:36:07.92 |
+33:19:08.7 |
HIP 12200 |
28.46 |
| 2026-05-30 00:00 |
02:36:10.26 |
+33:19:21.3 |
HIP 12200 |
28.45 |
| 2026-05-30 12:00 |
02:36:12.60 |
+33:19:33.9 |
HIP 12200 |
28.44 |
| 2026-05-31 00:00 |
02:36:14.93 |
+33:19:46.6 |
HIP 12200 |
28.45 |
| 2026-05-31 12:00 |
02:36:17.25 |
+33:19:59.3 |
HIP 12200 |
28.46 |
| 2026-06-01 00:00 |
02:36:19.56 |
+33:20:12.0 |
HIP 12200 |
28.49 |
| 2026-06-01 12:00 |
02:36:21.85 |
+33:20:24.7 |
HIP 12200 |
28.53 |
| 2026-06-02 00:00 |
02:36:24.14 |
+33:20:37.5 |
HIP 12200 |
28.58 |