| 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) |
| 2026-09-20 00:00 |
08:45:43.81 |
+13:39:58.1 |
HIP 42865 |
24.36 |
| 2026-09-20 12:00 |
08:46:05.14 |
+13:38:51.2 |
HIP 43018 |
23.07 |
| 2026-09-21 00:00 |
08:46:26.38 |
+13:37:44.4 |
HIP 43018 |
22.88 |
| 2026-09-21 12:00 |
08:46:47.53 |
+13:36:37.8 |
HIP 43018 |
23.88 |
| 2026-09-22 00:00 |
08:47:08.58 |
+13:35:31.3 |
HIP 43018 |
25.92 |
| 2026-09-22 12:00 |
08:47:29.54 |
+13:34:25.0 |
HIP 43018 |
28.76 |
| 2026-09-23 00:00 |
08:47:50.40 |
+13:33:18.9 |
HIP 43018 |
32.19 |
| 2026-09-23 12:00 |
08:48:11.17 |
+13:32:12.9 |
HIP 43343 |
34.02 |
| 2026-09-24 00:00 |
08:48:31.84 |
+13:31:07.2 |
HIP 43343 |
31.74 |
| 2026-09-24 12:00 |
08:48:52.41 |
+13:30:01.6 |
HIP 43343 |
30.18 |
| 2026-09-25 00:00 |
08:49:12.88 |
+13:28:56.2 |
HIP 43343 |
29.44 |
| 2026-09-25 12:00 |
08:49:33.25 |
+13:27:51.0 |
HIP 43343 |
29.57 |
| 2026-09-26 00:00 |
08:49:53.53 |
+13:26:46.0 |
HIP 43343 |
30.54 |
| 2026-09-26 12:00 |
08:50:13.70 |
+13:25:41.2 |
HIP 43441 |
28.09 |
| 2026-09-27 00:00 |
08:50:33.77 |
+13:24:36.7 |
HIP 43441 |
25.86 |
| 2026-09-27 12:00 |
08:50:53.74 |
+13:23:32.3 |
HIP 43569 |
23.94 |
| 2026-09-28 00:00 |
08:51:13.61 |
+13:22:28.2 |
HIP 43569 |
19.10 |
| 2026-09-28 12:00 |
08:51:33.37 |
+13:21:24.3 |
HIP 43569 |
14.37 |
| 2026-09-29 00:00 |
08:51:53.03 |
+13:20:20.7 |
HIP 43569 |
9.84 |
| 2026-09-29 12:00 |
08:52:12.59 |
+13:19:17.3 |
HIP 43569 |
5.96 |
| 2026-09-30 00:00 |
08:52:32.04 |
+13:18:14.1 |
HIP 43569 |
4.65 |
| 2026-09-30 12:00 |
08:52:51.38 |
+13:17:11.2 |
HIP 43569 |
7.37 |
| 2026-10-01 00:00 |
08:53:10.62 |
+13:16:08.6 |
HIP 43569 |
11.54 |
| 2026-10-01 12:00 |
08:53:29.74 |
+13:15:06.3 |
HIP 43569 |
16.03 |
| 2026-10-02 00:00 |
08:53:48.76 |
+13:14:04.2 |
HIP 43569 |
20.62 |
| 2026-10-02 12:00 |
08:54:07.67 |
+13:13:02.4 |
HIP 43755 |
22.67 |
| 2026-10-03 00:00 |
08:54:26.47 |
+13:12:00.9 |
HIP 43755 |
22.20 |
| 2026-10-03 12:00 |
08:54:45.16 |
+13:10:59.7 |
HIP 43755 |
22.70 |
| 2026-10-04 00:00 |
08:55:03.73 |
+13:09:58.8 |
HIP 43755 |
24.09 |
| 2026-10-04 12:00 |
08:55:22.19 |
+13:08:58.3 |
HIP 43755 |
26.23 |
| 2026-10-05 00:00 |
08:55:40.54 |
+13:07:58.0 |
HIP 43755 |
28.93 |
| 2026-10-05 12:00 |
08:55:58.77 |
+13:06:58.1 |
HIP 43755 |
32.03 |
| 2026-10-06 00:00 |
08:56:16.89 |
+13:05:58.5 |
HIP 43755 |
35.43 |
| 2026-10-06 12:00 |
08:56:34.89 |
+13:04:59.2 |
HIP 44102 |
35.31 |
| 2026-10-07 00:00 |
08:56:52.77 |
+13:04:00.3 |
HIP 44102 |
30.84 |
| 2026-10-07 12:00 |
08:57:10.53 |
+13:03:01.8 |
HIP 44102 |
26.41 |
| 2026-10-08 00:00 |
08:57:28.17 |
+13:02:03.6 |
HIP 44102 |
22.01 |
| 2026-10-08 12:00 |
08:57:45.69 |
+13:01:05.8 |
HIP 44102 |
17.64 |
| 2026-10-09 00:00 |
08:58:03.08 |
+13:00:08.4 |
HIP 44102 |
13.31 |
| 2026-10-09 12:00 |
08:58:20.36 |
+12:59:11.3 |
HIP 44102 |
9.01 |
| 2026-10-10 00:00 |
08:58:37.51 |
+12:58:14.7 |
HIP 44102 |
4.78 |
| 2026-10-10 12:00 |
08:58:54.54 |
+12:57:18.5 |
HIP 44102 |
1.09 |
| 2026-10-11 00:00 |
08:59:11.44 |
+12:56:22.6 |
HIP 44102 |
3.93 |