| Parameter |
Value |
| Designation |
438P/Christensen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2005-04-12T02:55:56.516160Z |
| Orbit solution date (soln_date, UTC) |
2026-06-09T11:12:48Z |
| Obs used |
115 |
| NEO |
- |
| M1 |
17.500 |
| K1 |
5.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-07-31T10:04:40.224000Z |
| Discovery magnitude (MPC) |
22.50 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-08-09.0000000 |
| e |
0.42236565 |
| q (au) |
2.209059 |
| a (au) |
3.824320 |
| i (deg) |
8.337130 |
| Ω (om, deg) |
260.604941 |
| ω (w, deg) |
58.403241 |
| M (ma, deg) |
160.105137 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.632 + 3.815\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.632 |
| n |
3.815 |
| gf |
1.000 |
| gb |
-0.930 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
13:45:18.25 |
-15:36:37.5 |
HIP 67139 |
10.25 |
| 2026-09-20 12:00 |
13:45:54.89 |
-15:39:17.2 |
HIP 67139 |
8.27 |
| 2026-09-21 00:00 |
13:46:31.64 |
-15:41:57.3 |
HIP 67139 |
14.21 |
| 2026-09-21 12:00 |
13:47:08.48 |
-15:44:37.7 |
HIP 67139 |
22.51 |
| 2026-09-22 00:00 |
13:47:45.42 |
-15:47:18.5 |
HIP 67328 |
16.89 |
| 2026-09-22 12:00 |
13:48:22.46 |
-15:49:59.5 |
HIP 67328 |
15.06 |
| 2026-09-23 00:00 |
13:48:59.60 |
-15:52:41.0 |
HIP 67328 |
18.48 |
| 2026-09-23 12:00 |
13:49:36.83 |
-15:55:22.7 |
HIP 67328 |
25.13 |
| 2026-09-24 00:00 |
13:50:14.17 |
-15:58:04.7 |
HIP 67328 |
33.12 |
| 2026-09-24 12:00 |
13:50:51.59 |
-16:00:47.1 |
HIP 67784 |
33.74 |
| 2026-09-25 00:00 |
13:51:29.12 |
-16:03:29.7 |
HIP 67784 |
24.96 |
| 2026-09-25 12:00 |
13:52:06.74 |
-16:06:12.7 |
HIP 67784 |
16.89 |
| 2026-09-26 00:00 |
13:52:44.45 |
-16:08:55.9 |
HIP 67784 |
11.19 |
| 2026-09-26 12:00 |
13:53:22.26 |
-16:11:39.4 |
HIP 67784 |
12.02 |
| 2026-09-27 00:00 |
13:54:00.17 |
-16:14:23.1 |
HIP 67784 |
18.55 |
| 2026-09-27 12:00 |
13:54:38.17 |
-16:17:07.2 |
HIP 68007 |
16.43 |
| 2026-09-28 00:00 |
13:55:16.26 |
-16:19:51.5 |
HIP 68007 |
12.23 |
| 2026-09-28 12:00 |
13:55:54.45 |
-16:22:36.0 |
HIP 68090 |
13.38 |
| 2026-09-29 00:00 |
13:56:32.74 |
-16:25:20.8 |
HIP 68090 |
13.64 |
| 2026-09-29 12:00 |
13:57:11.11 |
-16:28:05.8 |
HIP 68090 |
19.43 |
| 2026-09-30 00:00 |
13:57:49.59 |
-16:30:51.0 |
HIP 68090 |
27.47 |
| 2026-09-30 12:00 |
13:58:28.15 |
-16:33:36.5 |
HIP 68090 |
36.31 |
| 2026-10-01 00:00 |
13:59:06.81 |
-16:36:22.2 |
HIP 68451 |
30.13 |
| 2026-10-01 12:00 |
13:59:45.56 |
-16:39:08.1 |
HIP 68451 |
25.13 |
| 2026-10-02 00:00 |
14:00:24.41 |
-16:41:54.2 |
HIP 68451 |
23.30 |
| 2026-10-02 12:00 |
14:01:03.35 |
-16:44:40.5 |
HIP 68451 |
25.37 |
| 2026-10-03 00:00 |
14:01:42.38 |
-16:47:27.1 |
HIP 68451 |
30.57 |
| 2026-10-03 12:00 |
14:02:21.50 |
-16:50:13.7 |
HIP 68643 |
33.39 |
| 2026-10-04 00:00 |
14:03:00.71 |
-16:53:00.6 |
HIP 68643 |
29.02 |
| 2026-10-04 12:00 |
14:03:40.02 |
-16:55:47.7 |
HIP 68643 |
27.59 |
| 2026-10-05 00:00 |
14:04:19.42 |
-16:58:34.9 |
HIP 68643 |
29.53 |
| 2026-10-05 12:00 |
14:04:58.91 |
-17:01:22.2 |
HIP 68643 |
34.31 |
| 2026-10-06 00:00 |
14:05:38.49 |
-17:04:09.7 |
HIP 68918 |
26.64 |
| 2026-10-06 12:00 |
14:06:18.16 |
-17:06:57.4 |
HIP 68918 |
20.73 |
| 2026-10-07 00:00 |
14:06:57.92 |
-17:09:45.2 |
HIP 68918 |
18.58 |
| 2026-10-07 12:00 |
14:07:37.77 |
-17:12:33.1 |
HIP 68918 |
21.37 |
| 2026-10-08 00:00 |
14:08:17.71 |
-17:15:21.2 |
HIP 68918 |
27.68 |
| 2026-10-08 12:00 |
14:08:57.74 |
-17:18:09.3 |
HIP 69111 |
26.08 |
| 2026-10-09 00:00 |
14:09:37.86 |
-17:20:57.6 |
HIP 69111 |
25.81 |
| 2026-10-09 12:00 |
14:10:18.07 |
-17:23:45.9 |
HIP 69314 |
26.00 |
| 2026-10-10 00:00 |
14:10:58.36 |
-17:26:34.4 |
HIP 69314 |
25.36 |
| 2026-10-10 12:00 |
14:11:38.74 |
-17:29:22.9 |
HIP 69362 |
23.89 |
| 2026-10-11 00:00 |
14:12:19.21 |
-17:32:11.5 |
HIP 69362 |
21.75 |