| Parameter |
Value |
| Designation |
287P/Christensen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2023-07-05T04:20:07.710720Z |
| Orbit solution date (soln_date, UTC) |
2025-10-30T09:37:11Z |
| Obs used |
270 |
| NEO |
- |
| M1 |
9.600 |
| K1 |
15.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-12-28.0000000 |
| e |
0.27096868 |
| q (au) |
3.038241 |
| a (au) |
4.167503 |
| i (deg) |
16.320345 |
| Ω (om, deg) |
139.045236 |
| ω (w, deg) |
188.874131 |
| M (ma, deg) |
253.514373 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.191 + 5.080\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.191 |
| n |
5.080 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2022-05-13 |
2023-07-04 |
+6.3005 |
-3.721 |
| 2023-07-12 |
2024-12-26 |
+1.9974 |
-0.830 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
08:01:38.53 |
+15:33:30.9 |
HIP 39125 |
21.42 |
| 2026-07-29 12:00 |
08:02:05.82 |
+15:32:38.0 |
HIP 39341 |
22.75 |
| 2026-07-30 00:00 |
08:02:33.08 |
+15:31:44.8 |
HIP 39341 |
21.05 |
| 2026-07-30 12:00 |
08:03:00.32 |
+15:30:51.2 |
HIP 39341 |
21.36 |
| 2026-07-31 00:00 |
08:03:27.53 |
+15:29:57.2 |
HIP 39515 |
18.10 |
| 2026-07-31 12:00 |
08:03:54.72 |
+15:29:02.9 |
HIP 39515 |
12.02 |
| 2026-08-01 00:00 |
08:04:21.88 |
+15:28:08.3 |
HIP 39515 |
6.98 |
| 2026-08-01 12:00 |
08:04:49.02 |
+15:27:13.3 |
HIP 39515 |
6.34 |
| 2026-08-02 00:00 |
08:05:16.14 |
+15:26:18.0 |
HIP 39515 |
10.90 |
| 2026-08-02 12:00 |
08:05:43.23 |
+15:25:22.3 |
HIP 39650 |
7.73 |
| 2026-08-03 00:00 |
08:06:10.29 |
+15:24:26.3 |
HIP 39650 |
3.65 |
| 2026-08-03 12:00 |
08:06:37.32 |
+15:23:30.0 |
HIP 39650 |
7.32 |
| 2026-08-04 00:00 |
08:07:04.32 |
+15:22:33.4 |
HIP 39708 |
13.30 |
| 2026-08-04 12:00 |
08:07:31.30 |
+15:21:36.4 |
HIP 39793 |
8.92 |
| 2026-08-05 00:00 |
08:07:58.24 |
+15:20:39.2 |
HIP 39793 |
8.28 |
| 2026-08-05 12:00 |
08:08:25.16 |
+15:19:41.6 |
HIP 39793 |
11.99 |
| 2026-08-06 00:00 |
08:08:52.05 |
+15:18:43.7 |
HIP 39793 |
17.47 |
| 2026-08-06 12:00 |
08:09:18.90 |
+15:17:45.5 |
HIP 39793 |
23.49 |
| 2026-08-07 00:00 |
08:09:45.72 |
+15:16:47.0 |
HIP 39793 |
29.74 |
| 2026-08-07 12:00 |
08:10:12.51 |
+15:15:48.2 |
HIP 39793 |
36.08 |
| 2026-08-08 00:00 |
08:10:39.27 |
+15:14:49.1 |
HIP 40058 |
37.35 |
| 2026-08-08 12:00 |
08:11:05.99 |
+15:13:49.7 |
HIP 40058 |
36.10 |
| 2026-08-09 00:00 |
08:11:32.68 |
+15:12:50.0 |
HIP 40058 |
36.00 |
| 2026-08-09 12:00 |
08:11:59.34 |
+15:11:50.1 |
HIP 40058 |
37.06 |
| 2026-08-10 00:00 |
08:12:25.95 |
+15:10:49.9 |
HIP 40194 |
35.64 |
| 2026-08-10 12:00 |
08:12:52.54 |
+15:09:49.3 |
HIP 40420 |
33.53 |
| 2026-08-11 00:00 |
08:13:19.08 |
+15:08:48.6 |
HIP 40420 |
27.06 |
| 2026-08-11 12:00 |
08:13:45.59 |
+15:07:47.5 |
HIP 40420 |
20.61 |
| 2026-08-12 00:00 |
08:14:12.05 |
+15:06:46.2 |
HIP 40420 |
14.19 |
| 2026-08-12 12:00 |
08:14:38.48 |
+15:05:44.6 |
HIP 40420 |
7.87 |
| 2026-08-13 00:00 |
08:15:04.87 |
+15:04:42.8 |
HIP 40420 |
2.41 |
| 2026-08-13 12:00 |
08:15:31.21 |
+15:03:40.8 |
HIP 40420 |
5.73 |
| 2026-08-14 00:00 |
08:15:57.52 |
+15:02:38.4 |
HIP 40420 |
11.95 |
| 2026-08-14 12:00 |
08:16:23.78 |
+15:01:35.9 |
HIP 40420 |
18.31 |
| 2026-08-15 00:00 |
08:16:50.00 |
+15:00:33.1 |
HIP 40420 |
24.69 |
| 2026-08-15 12:00 |
08:17:16.18 |
+14:59:30.1 |
HIP 40759 |
28.02 |
| 2026-08-16 00:00 |
08:17:42.31 |
+14:58:26.9 |
HIP 40759 |
21.83 |
| 2026-08-16 12:00 |
08:18:08.39 |
+14:57:23.4 |
HIP 40759 |
15.82 |
| 2026-08-17 00:00 |
08:18:34.43 |
+14:56:19.8 |
HIP 40759 |
10.30 |
| 2026-08-17 12:00 |
08:19:00.42 |
+14:55:15.9 |
HIP 40759 |
6.56 |
| 2026-08-18 00:00 |
08:19:26.37 |
+14:54:11.8 |
HIP 40759 |
7.82 |
| 2026-08-18 12:00 |
08:19:52.27 |
+14:53:07.5 |
HIP 40759 |
12.65 |
| 2026-08-19 00:00 |
08:20:18.12 |
+14:52:03.0 |
HIP 40759 |
18.41 |