| Parameter |
Value |
| Designation |
71P/Clark |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-06-30T08:48:25.663680Z |
| Orbit solution date (soln_date, UTC) |
2026-03-07T15:24:44Z |
| 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 |
+1.1015 |
-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) |
| 2026-06-01 00:00 |
06:32:15.91 |
+28:37:14.1 |
HIP 31219 |
19.28 |
| 2026-06-01 12:00 |
06:32:45.48 |
+28:36:51.5 |
HIP 31219 |
16.96 |
| 2026-06-02 00:00 |
06:33:15.10 |
+28:36:28.7 |
HIP 31219 |
16.99 |
| 2026-06-02 12:00 |
06:33:44.77 |
+28:36:05.7 |
HIP 31219 |
19.35 |
| 2026-06-03 00:00 |
06:34:14.50 |
+28:35:42.5 |
HIP 31444 |
16.23 |
| 2026-06-03 12:00 |
06:34:44.29 |
+28:35:19.0 |
HIP 31444 |
11.13 |
| 2026-06-04 00:00 |
06:35:14.13 |
+28:34:55.3 |
HIP 31444 |
8.37 |
| 2026-06-04 12:00 |
06:35:44.02 |
+28:34:31.4 |
HIP 31444 |
10.12 |
| 2026-06-05 00:00 |
06:36:13.96 |
+28:34:07.3 |
HIP 31444 |
14.89 |
| 2026-06-05 12:00 |
06:36:43.96 |
+28:33:42.9 |
HIP 31444 |
20.70 |
| 2026-06-06 00:00 |
06:37:14.01 |
+28:33:18.3 |
HIP 31767 |
19.83 |
| 2026-06-06 12:00 |
06:37:44.10 |
+28:32:53.5 |
HIP 31767 |
14.08 |
| 2026-06-07 00:00 |
06:38:14.25 |
+28:32:28.4 |
HIP 31767 |
9.52 |
| 2026-06-07 12:00 |
06:38:44.45 |
+28:32:03.1 |
HIP 31767 |
8.43 |
| 2026-06-08 00:00 |
06:39:14.69 |
+28:31:37.6 |
HIP 31856 |
10.45 |
| 2026-06-08 12:00 |
06:39:44.98 |
+28:31:11.8 |
HIP 31856 |
9.28 |
| 2026-06-09 00:00 |
06:40:15.32 |
+28:30:45.8 |
HIP 31856 |
12.33 |
| 2026-06-09 12:00 |
06:40:45.70 |
+28:30:19.6 |
HIP 31856 |
17.54 |
| 2026-06-10 00:00 |
06:41:16.13 |
+28:29:53.1 |
HIP 32019 |
18.12 |
| 2026-06-10 12:00 |
06:41:46.60 |
+28:29:26.4 |
HIP 32019 |
18.53 |
| 2026-06-11 00:00 |
06:42:17.12 |
+28:28:59.4 |
HIP 32225 |
18.47 |
| 2026-06-11 12:00 |
06:42:47.68 |
+28:28:32.2 |
HIP 32225 |
11.95 |
| 2026-06-12 00:00 |
06:43:18.29 |
+28:28:04.7 |
HIP 32225 |
5.90 |
| 2026-06-12 12:00 |
06:43:48.93 |
+28:27:37.1 |
HIP 32225 |
4.23 |
| 2026-06-13 00:00 |
06:44:19.62 |
+28:27:09.1 |
HIP 32279 |
5.01 |
| 2026-06-13 12:00 |
06:44:50.34 |
+28:26:41.0 |
HIP 32279 |
7.99 |
| 2026-06-14 00:00 |
06:45:21.11 |
+28:26:12.6 |
HIP 32279 |
13.95 |
| 2026-06-14 12:00 |
06:45:51.91 |
+28:25:43.9 |
HIP 32279 |
20.44 |
| 2026-06-15 00:00 |
06:46:22.75 |
+28:25:15.0 |
HIP 32279 |
27.08 |
| 2026-06-15 12:00 |
06:46:53.63 |
+28:24:45.9 |
HIP 32700 |
32.94 |
| 2026-06-16 00:00 |
06:47:24.54 |
+28:24:16.5 |
HIP 32700 |
26.53 |
| 2026-06-16 12:00 |
06:47:55.48 |
+28:23:46.9 |
HIP 32700 |
20.39 |
| 2026-06-17 00:00 |
06:48:26.47 |
+28:23:17.0 |
HIP 32700 |
14.83 |
| 2026-06-17 12:00 |
06:48:57.48 |
+28:22:46.9 |
HIP 32737 |
10.32 |
| 2026-06-18 00:00 |
06:49:28.52 |
+28:22:16.5 |
HIP 32737 |
4.26 |
| 2026-06-18 12:00 |
06:49:59.60 |
+28:21:45.9 |
HIP 32737 |
4.86 |
| 2026-06-19 00:00 |
06:50:30.71 |
+28:21:15.1 |
HIP 32737 |
11.11 |
| 2026-06-19 12:00 |
06:51:01.85 |
+28:20:44.0 |
HIP 32737 |
17.82 |
| 2026-06-20 00:00 |
06:51:33.01 |
+28:20:12.7 |
HIP 32737 |
24.63 |
| 2026-06-20 12:00 |
06:52:04.20 |
+28:19:41.2 |
HIP 33129 |
24.88 |
| 2026-06-21 00:00 |
06:52:35.43 |
+28:19:09.4 |
HIP 33129 |
18.22 |
| 2026-06-21 12:00 |
06:53:06.67 |
+28:18:37.3 |
HIP 33129 |
11.81 |
| 2026-06-22 00:00 |
06:53:37.95 |
+28:18:05.1 |
HIP 33129 |
6.51 |