| Parameter |
Value |
| Designation |
170P/Christensen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2023-04-20T08:14:01.852800Z |
| Orbit solution date (soln_date, UTC) |
2025-04-11T15:35:57Z |
| Obs used |
987 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
13.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-05-22.0000000 |
| e |
0.30421190 |
| q (au) |
2.923152 |
| a (au) |
4.201211 |
| i (deg) |
10.124302 |
| Ω (om, deg) |
142.923756 |
| ω (w, deg) |
225.533342 |
| M (ma, deg) |
321.846548 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.260 + 5.247\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.260 |
| n |
5.247 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2021-06-30 |
2022-11-28 |
+5.3605 |
-1.798 |
| 2023-07-15 |
2024-03-18 |
-13.6949 |
+6.498 |
| 2024-03-18 |
2025-01-24 |
+9.8383 |
-5.868 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
10:03:58.88 |
+14:50:34.6 |
HIP 49214 |
18.31 |
| 2026-06-01 12:00 |
10:04:11.57 |
+14:49:33.4 |
HIP 49214 |
21.30 |
| 2026-06-02 00:00 |
10:04:24.38 |
+14:48:31.4 |
HIP 49395 |
21.71 |
| 2026-06-02 12:00 |
10:04:37.33 |
+14:47:28.6 |
HIP 49395 |
21.54 |
| 2026-06-03 00:00 |
10:04:50.41 |
+14:46:25.1 |
HIP 49395 |
21.88 |
| 2026-06-03 12:00 |
10:05:03.61 |
+14:45:20.9 |
HIP 49395 |
22.73 |
| 2026-06-04 00:00 |
10:05:16.95 |
+14:44:15.9 |
HIP 49395 |
24.03 |
| 2026-06-04 12:00 |
10:05:30.42 |
+14:43:10.2 |
HIP 49395 |
25.74 |
| 2026-06-05 00:00 |
10:05:44.01 |
+14:42:03.7 |
HIP 49395 |
27.79 |
| 2026-06-05 12:00 |
10:05:57.73 |
+14:40:56.6 |
HIP 49395 |
30.13 |
| 2026-06-06 00:00 |
10:06:11.57 |
+14:39:48.6 |
HIP 49395 |
32.70 |
| 2026-06-06 12:00 |
10:06:25.54 |
+14:38:40.0 |
HIP 49551 |
30.52 |
| 2026-06-07 00:00 |
10:06:39.63 |
+14:37:30.7 |
HIP 49551 |
28.57 |
| 2026-06-07 12:00 |
10:06:53.85 |
+14:36:20.6 |
HIP 49551 |
26.94 |
| 2026-06-08 00:00 |
10:07:08.18 |
+14:35:09.8 |
HIP 49551 |
25.72 |
| 2026-06-08 12:00 |
10:07:22.64 |
+14:33:58.3 |
HIP 49551 |
24.98 |
| 2026-06-09 00:00 |
10:07:37.22 |
+14:32:46.1 |
HIP 49551 |
24.77 |
| 2026-06-09 12:00 |
10:07:51.93 |
+14:31:33.2 |
HIP 49551 |
25.12 |
| 2026-06-10 00:00 |
10:08:06.74 |
+14:30:19.6 |
HIP 49551 |
26.03 |
| 2026-06-10 12:00 |
10:08:21.68 |
+14:29:05.3 |
HIP 49551 |
27.45 |
| 2026-06-11 00:00 |
10:08:36.74 |
+14:27:50.4 |
HIP 49551 |
29.32 |
| 2026-06-11 12:00 |
10:08:51.91 |
+14:26:34.7 |
HIP 49820 |
29.86 |
| 2026-06-12 00:00 |
10:09:07.20 |
+14:25:18.4 |
HIP 49820 |
26.54 |
| 2026-06-12 12:00 |
10:09:22.60 |
+14:24:01.3 |
HIP 49866 |
23.27 |
| 2026-06-13 00:00 |
10:09:38.12 |
+14:22:43.6 |
HIP 49866 |
19.98 |
| 2026-06-13 12:00 |
10:09:53.75 |
+14:21:25.3 |
HIP 49866 |
16.97 |
| 2026-06-14 00:00 |
10:10:09.49 |
+14:20:06.2 |
HIP 49866 |
14.43 |
| 2026-06-14 12:00 |
10:10:25.34 |
+14:18:46.5 |
HIP 49866 |
12.69 |
| 2026-06-15 00:00 |
10:10:41.31 |
+14:17:26.2 |
HIP 49866 |
12.11 |
| 2026-06-15 12:00 |
10:10:57.38 |
+14:16:05.2 |
HIP 49866 |
12.89 |
| 2026-06-16 00:00 |
10:11:13.56 |
+14:14:43.5 |
HIP 49866 |
14.84 |
| 2026-06-16 12:00 |
10:11:29.85 |
+14:13:21.2 |
HIP 49866 |
17.59 |
| 2026-06-17 00:00 |
10:11:46.25 |
+14:11:58.3 |
HIP 49866 |
20.84 |
| 2026-06-17 12:00 |
10:12:02.76 |
+14:10:34.7 |
HIP 49866 |
24.41 |
| 2026-06-18 00:00 |
10:12:19.36 |
+14:09:10.5 |
HIP 49866 |
28.19 |
| 2026-06-18 12:00 |
10:12:36.08 |
+14:07:45.7 |
HIP 50124 |
24.93 |
| 2026-06-19 00:00 |
10:12:52.89 |
+14:06:20.3 |
HIP 50124 |
20.89 |
| 2026-06-19 12:00 |
10:13:09.81 |
+14:04:54.3 |
HIP 50124 |
16.97 |
| 2026-06-20 00:00 |
10:13:26.83 |
+14:03:27.6 |
HIP 50124 |
13.29 |
| 2026-06-20 12:00 |
10:13:43.94 |
+14:02:00.3 |
HIP 50124 |
10.16 |
| 2026-06-21 00:00 |
10:14:01.16 |
+14:00:32.5 |
HIP 50124 |
8.27 |
| 2026-06-21 12:00 |
10:14:18.47 |
+13:59:04.0 |
HIP 50124 |
8.54 |
| 2026-06-22 00:00 |
10:14:35.89 |
+13:57:35.0 |
HIP 50124 |
10.84 |