170P/Christensen
| 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 |
0.999 |
| gb |
-0.588 |
| 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) |
| 2026-02-03 00:00 |
10:26:49.68 |
+11:31:35.8 |
HIP 51179 |
13.74 |
| 2026-02-03 12:00 |
10:26:34.73 |
+11:33:37.7 |
HIP 51179 |
17.26 |
| 2026-02-04 00:00 |
10:26:19.68 |
+11:35:40.1 |
HIP 51179 |
21.05 |
| 2026-02-04 12:00 |
10:26:04.53 |
+11:37:42.9 |
HIP 51179 |
24.99 |
| 2026-02-05 00:00 |
10:25:49.29 |
+11:39:46.2 |
HIP 51179 |
29.04 |
| 2026-02-05 12:00 |
10:25:33.94 |
+11:41:49.8 |
HIP 51179 |
33.17 |
| 2026-02-06 00:00 |
10:25:18.51 |
+11:43:53.8 |
HIP 51179 |
37.35 |
| 2026-02-06 12:00 |
10:25:02.98 |
+11:45:58.1 |
HIP 51179 |
41.58 |
| 2026-02-07 00:00 |
10:24:47.37 |
+11:48:02.8 |
HIP 50802 |
41.43 |
| 2026-02-07 12:00 |
10:24:31.67 |
+11:50:07.8 |
HIP 50802 |
37.06 |
| 2026-02-08 00:00 |
10:24:15.89 |
+11:52:13.1 |
HIP 50802 |
32.67 |
| 2026-02-08 12:00 |
10:24:00.03 |
+11:54:18.7 |
HIP 50802 |
28.27 |
| 2026-02-09 00:00 |
10:23:44.09 |
+11:56:24.5 |
HIP 50802 |
23.84 |
| 2026-02-09 12:00 |
10:23:28.08 |
+11:58:30.6 |
HIP 50802 |
19.41 |
| 2026-02-10 00:00 |
10:23:12.00 |
+12:00:36.9 |
HIP 50802 |
14.96 |
| 2026-02-10 12:00 |
10:22:55.85 |
+12:02:43.4 |
HIP 50802 |
10.51 |
| 2026-02-11 00:00 |
10:22:39.64 |
+12:04:50.0 |
HIP 50802 |
6.07 |
| 2026-02-11 12:00 |
10:22:23.36 |
+12:06:56.9 |
HIP 50802 |
1.93 |
| 2026-02-12 00:00 |
10:22:07.03 |
+12:09:03.8 |
HIP 50802 |
3.35 |
| 2026-02-12 12:00 |
10:21:50.64 |
+12:11:10.9 |
HIP 50802 |
7.73 |
| 2026-02-13 00:00 |
10:21:34.19 |
+12:13:18.1 |
HIP 50802 |
12.23 |
| 2026-02-13 12:00 |
10:21:17.70 |
+12:15:25.4 |
HIP 50802 |
16.77 |
| 2026-02-14 00:00 |
10:21:01.16 |
+12:17:32.7 |
HIP 50802 |
21.32 |
| 2026-02-14 12:00 |
10:20:44.57 |
+12:19:40.1 |
HIP 50802 |
25.89 |
| 2026-02-15 00:00 |
10:20:27.94 |
+12:21:47.5 |
HIP 50802 |
30.47 |
| 2026-02-15 12:00 |
10:20:11.28 |
+12:23:54.8 |
HIP 50473 |
29.95 |
| 2026-02-16 00:00 |
10:19:54.58 |
+12:26:02.2 |
HIP 50473 |
25.35 |
| 2026-02-16 12:00 |
10:19:37.85 |
+12:28:09.5 |
HIP 50473 |
20.75 |
| 2026-02-17 00:00 |
10:19:21.09 |
+12:30:16.7 |
HIP 50473 |
16.15 |
| 2026-02-17 12:00 |
10:19:04.31 |
+12:32:23.9 |
HIP 50473 |
11.54 |
| 2026-02-18 00:00 |
10:18:47.51 |
+12:34:30.9 |
HIP 50473 |
6.93 |
| 2026-02-18 12:00 |
10:18:30.68 |
+12:36:37.8 |
HIP 50473 |
2.34 |
| 2026-02-19 00:00 |
10:18:13.85 |
+12:38:44.6 |
HIP 50473 |
2.37 |
| 2026-02-19 12:00 |
10:17:57.00 |
+12:40:51.1 |
HIP 50473 |
6.96 |
| 2026-02-20 00:00 |
10:17:40.14 |
+12:42:57.5 |
HIP 50473 |
11.57 |
| 2026-02-20 12:00 |
10:17:23.27 |
+12:45:03.7 |
HIP 50357 |
11.72 |
| 2026-02-21 00:00 |
10:17:06.41 |
+12:47:09.6 |
HIP 50357 |
8.02 |
| 2026-02-21 12:00 |
10:16:49.54 |
+12:49:15.3 |
HIP 50357 |
5.82 |
| 2026-02-22 00:00 |
10:16:32.68 |
+12:51:20.7 |
HIP 50357 |
6.78 |
| 2026-02-22 12:00 |
10:16:15.83 |
+12:53:25.9 |
HIP 50357 |
10.03 |
| 2026-02-23 00:00 |
10:15:58.99 |
+12:55:30.7 |
HIP 50357 |
14.06 |
| 2026-02-23 12:00 |
10:15:42.16 |
+12:57:35.1 |
HIP 50357 |
18.35 |
| 2026-02-24 00:00 |
10:15:25.35 |
+12:59:39.3 |
HIP 50357 |
22.75 |