71P/Clark
| Parameter |
Value |
| Designation |
71P/Clark |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-06-30T08:48:25.663680Z |
| Orbit solution date (soln_date, UTC) |
2024-12-04T09:48:22Z |
| Obs used |
1360 |
| NEO |
- |
| M1 |
11.100 |
| K1 |
14.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-06-01.0000000 |
| e |
0.49450343 |
| q (au) |
1.586677 |
| a (au) |
3.138847 |
| i (deg) |
9.444491 |
| Ω (om, deg) |
59.443537 |
| ω (w, deg) |
208.969656 |
| M (ma, deg) |
124.176492 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.843 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.843 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.916 |
| 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 |
| 2022-01-06 |
2023-06-09 |
+13.0262 |
-5.820 |
| 2023-06-09 |
2023-01-22 |
+8.6983 |
-3.636 |
| 2023-01-22 |
2024-12-03 |
+1.1016 |
-0.517 |
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 |
05:39:15.48 |
+29:42:10.1 |
HIP 26619 |
8.44 |
| 2026-02-03 12:00 |
05:39:03.38 |
+29:41:49.2 |
HIP 26619 |
10.00 |
| 2026-02-04 00:00 |
05:38:51.54 |
+29:41:28.1 |
HIP 26619 |
11.91 |
| 2026-02-04 12:00 |
05:38:39.96 |
+29:41:06.8 |
HIP 26619 |
14.00 |
| 2026-02-05 00:00 |
05:38:28.65 |
+29:40:45.4 |
HIP 26619 |
16.18 |
| 2026-02-05 12:00 |
05:38:17.59 |
+29:40:23.9 |
HIP 26619 |
18.38 |
| 2026-02-06 00:00 |
05:38:06.80 |
+29:40:02.1 |
HIP 26619 |
20.59 |
| 2026-02-06 12:00 |
05:37:56.28 |
+29:39:40.3 |
HIP 26619 |
22.78 |
| 2026-02-07 00:00 |
05:37:46.02 |
+29:39:18.3 |
HIP 26619 |
24.94 |
| 2026-02-07 12:00 |
05:37:36.03 |
+29:38:56.2 |
HIP 26619 |
27.07 |
| 2026-02-08 00:00 |
05:37:26.30 |
+29:38:34.0 |
HIP 26619 |
29.15 |
| 2026-02-08 12:00 |
05:37:16.84 |
+29:38:11.7 |
HIP 26619 |
31.19 |
| 2026-02-09 00:00 |
05:37:07.65 |
+29:37:49.3 |
HIP 26227 |
32.21 |
| 2026-02-09 12:00 |
05:36:58.72 |
+29:37:26.8 |
HIP 26227 |
30.53 |
| 2026-02-10 00:00 |
05:36:50.07 |
+29:37:04.2 |
HIP 26227 |
28.93 |
| 2026-02-10 12:00 |
05:36:41.68 |
+29:36:41.6 |
HIP 26227 |
27.41 |
| 2026-02-11 00:00 |
05:36:33.57 |
+29:36:18.9 |
HIP 26227 |
25.97 |
| 2026-02-11 12:00 |
05:36:25.72 |
+29:35:56.1 |
HIP 26227 |
24.62 |
| 2026-02-12 00:00 |
05:36:18.15 |
+29:35:33.3 |
HIP 26227 |
23.34 |
| 2026-02-12 12:00 |
05:36:10.84 |
+29:35:10.4 |
HIP 26227 |
22.16 |
| 2026-02-13 00:00 |
05:36:03.81 |
+29:34:47.6 |
HIP 26227 |
21.06 |
| 2026-02-13 12:00 |
05:35:57.05 |
+29:34:24.7 |
HIP 26227 |
20.05 |
| 2026-02-14 00:00 |
05:35:50.56 |
+29:34:01.8 |
HIP 26227 |
19.14 |
| 2026-02-14 12:00 |
05:35:44.34 |
+29:33:38.8 |
HIP 26227 |
18.31 |
| 2026-02-15 00:00 |
05:35:38.40 |
+29:33:15.9 |
HIP 26227 |
17.57 |
| 2026-02-15 12:00 |
05:35:32.72 |
+29:32:53.0 |
HIP 26227 |
16.91 |
| 2026-02-16 00:00 |
05:35:27.32 |
+29:32:30.0 |
HIP 26227 |
16.35 |
| 2026-02-16 12:00 |
05:35:22.19 |
+29:32:07.1 |
HIP 26227 |
15.86 |
| 2026-02-17 00:00 |
05:35:17.34 |
+29:31:44.3 |
HIP 26227 |
15.44 |
| 2026-02-17 12:00 |
05:35:12.75 |
+29:31:21.4 |
HIP 26227 |
15.10 |
| 2026-02-18 00:00 |
05:35:08.44 |
+29:30:58.6 |
HIP 26227 |
14.82 |
| 2026-02-18 12:00 |
05:35:04.40 |
+29:30:35.8 |
HIP 26227 |
14.59 |
| 2026-02-19 00:00 |
05:35:00.63 |
+29:30:13.1 |
HIP 26227 |
14.41 |
| 2026-02-19 12:00 |
05:34:57.13 |
+29:29:50.4 |
HIP 26227 |
14.26 |
| 2026-02-20 00:00 |
05:34:53.90 |
+29:29:27.8 |
HIP 26227 |
14.14 |
| 2026-02-20 12:00 |
05:34:50.95 |
+29:29:05.2 |
HIP 26227 |
14.05 |
| 2026-02-21 00:00 |
05:34:48.26 |
+29:28:42.7 |
HIP 26227 |
13.97 |
| 2026-02-21 12:00 |
05:34:45.84 |
+29:28:20.3 |
HIP 26227 |
13.89 |
| 2026-02-22 00:00 |
05:34:43.69 |
+29:27:57.9 |
HIP 26227 |
13.81 |
| 2026-02-22 12:00 |
05:34:41.81 |
+29:27:35.6 |
HIP 26227 |
13.73 |
| 2026-02-23 00:00 |
05:34:40.19 |
+29:27:13.4 |
HIP 26227 |
13.63 |
| 2026-02-23 12:00 |
05:34:38.85 |
+29:26:51.3 |
HIP 26227 |
13.52 |
| 2026-02-24 00:00 |
05:34:37.77 |
+29:26:29.3 |
HIP 26227 |
13.39 |