| Parameter |
Value |
| Designation |
C/2026 H3 (Bok) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-05-23T01:14:31.597440Z |
| Orbit solution date (soln_date, UTC) |
2026-05-19T10:12:02Z |
| Obs used |
59 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
11.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2026-04-27T11:09:21.312000Z |
| Discovery magnitude (MPC) |
20.88 G |
| Discovery observatory (MPC) |
V00 · Kitt Peak-Bok |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2026-03-05.0000000 |
| e |
1.00372394 |
| q (au) |
7.728219 |
| a (au) |
-2075.279272 |
| i (deg) |
142.567608 |
| Ω (om, deg) |
352.490926 |
| ω (w, deg) |
98.493167 |
| M (ma, deg) |
-0.000824 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.113 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.113 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-09-20 00:00 |
16:00:55.45 |
+13:53:40.1 |
HIP 78439 |
20.13 |
| 2026-09-20 12:00 |
16:00:54.29 |
+13:51:29.1 |
HIP 78439 |
17.93 |
| 2026-09-21 00:00 |
16:00:53.25 |
+13:49:18.5 |
HIP 78439 |
15.74 |
| 2026-09-21 12:00 |
16:00:52.32 |
+13:47:08.3 |
HIP 78439 |
13.57 |
| 2026-09-22 00:00 |
16:00:51.51 |
+13:44:58.6 |
HIP 78439 |
11.39 |
| 2026-09-22 12:00 |
16:00:50.80 |
+13:42:49.2 |
HIP 78439 |
9.23 |
| 2026-09-23 00:00 |
16:00:50.21 |
+13:40:40.2 |
HIP 78439 |
7.08 |
| 2026-09-23 12:00 |
16:00:49.73 |
+13:38:31.6 |
HIP 78439 |
4.93 |
| 2026-09-24 00:00 |
16:00:49.36 |
+13:36:23.5 |
HIP 78439 |
2.80 |
| 2026-09-24 12:00 |
16:00:49.10 |
+13:34:15.8 |
HIP 78439 |
0.67 |
| 2026-09-25 00:00 |
16:00:48.94 |
+13:32:08.5 |
HIP 78439 |
1.45 |
| 2026-09-25 12:00 |
16:00:48.89 |
+13:30:01.7 |
HIP 78439 |
3.57 |
| 2026-09-26 00:00 |
16:00:48.95 |
+13:27:55.4 |
HIP 78439 |
5.67 |
| 2026-09-26 12:00 |
16:00:49.12 |
+13:25:49.4 |
HIP 78439 |
7.77 |
| 2026-09-27 00:00 |
16:00:49.39 |
+13:23:44.0 |
HIP 78446 |
7.52 |
| 2026-09-27 12:00 |
16:00:49.77 |
+13:21:39.0 |
HIP 78446 |
5.45 |
| 2026-09-28 00:00 |
16:00:50.24 |
+13:19:34.5 |
HIP 78446 |
3.41 |
| 2026-09-28 12:00 |
16:00:50.82 |
+13:17:30.4 |
HIP 78446 |
1.45 |
| 2026-09-29 00:00 |
16:00:51.51 |
+13:15:26.9 |
HIP 78446 |
1.07 |
| 2026-09-29 12:00 |
16:00:52.29 |
+13:13:23.8 |
HIP 78446 |
2.94 |
| 2026-09-30 00:00 |
16:00:53.18 |
+13:11:21.2 |
HIP 78446 |
4.96 |
| 2026-09-30 12:00 |
16:00:54.16 |
+13:09:19.1 |
HIP 78446 |
6.98 |
| 2026-10-01 00:00 |
16:00:55.25 |
+13:07:17.5 |
HIP 78446 |
9.02 |
| 2026-10-01 12:00 |
16:00:56.43 |
+13:05:16.4 |
HIP 78446 |
11.04 |
| 2026-10-02 00:00 |
16:00:57.71 |
+13:03:15.9 |
HIP 78446 |
13.07 |
| 2026-10-02 12:00 |
16:00:59.09 |
+13:01:15.8 |
HIP 78446 |
15.09 |
| 2026-10-03 00:00 |
16:01:00.56 |
+12:59:16.3 |
HIP 78446 |
17.10 |
| 2026-10-03 12:00 |
16:01:02.13 |
+12:57:17.3 |
HIP 78446 |
19.11 |
| 2026-10-04 00:00 |
16:01:03.80 |
+12:55:18.8 |
HIP 78446 |
21.12 |
| 2026-10-04 12:00 |
16:01:05.56 |
+12:53:20.9 |
HIP 78446 |
23.12 |
| 2026-10-05 00:00 |
16:01:07.41 |
+12:51:23.6 |
HIP 78444 |
23.12 |
| 2026-10-05 12:00 |
16:01:09.35 |
+12:49:26.7 |
HIP 78444 |
21.29 |
| 2026-10-06 00:00 |
16:01:11.39 |
+12:47:30.5 |
HIP 78444 |
19.52 |
| 2026-10-06 12:00 |
16:01:13.52 |
+12:45:34.8 |
HIP 78444 |
17.81 |
| 2026-10-07 00:00 |
16:01:15.73 |
+12:43:39.7 |
HIP 78444 |
16.18 |
| 2026-10-07 12:00 |
16:01:18.04 |
+12:41:45.1 |
HIP 78444 |
14.65 |
| 2026-10-08 00:00 |
16:01:20.44 |
+12:39:51.2 |
HIP 78444 |
13.28 |
| 2026-10-08 12:00 |
16:01:22.92 |
+12:37:57.8 |
HIP 78444 |
12.09 |
| 2026-10-09 00:00 |
16:01:25.49 |
+12:36:05.0 |
HIP 78444 |
11.16 |
| 2026-10-09 12:00 |
16:01:28.14 |
+12:34:12.9 |
HIP 78444 |
10.54 |
| 2026-10-10 00:00 |
16:01:30.88 |
+12:32:21.3 |
HIP 78444 |
10.30 |
| 2026-10-10 12:00 |
16:01:33.71 |
+12:30:30.4 |
HIP 78444 |
10.46 |
| 2026-10-11 00:00 |
16:01:36.62 |
+12:28:40.0 |
HIP 78444 |
10.99 |