| 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) |
| 2026-07-29 00:00 |
07:32:38.86 |
+27:28:01.3 |
HIP 36718 |
6.91 |
| 2026-07-29 12:00 |
07:33:10.22 |
+27:27:13.9 |
HIP 36718 |
1.24 |
| 2026-07-30 00:00 |
07:33:41.57 |
+27:26:26.3 |
HIP 36718 |
7.31 |
| 2026-07-30 12:00 |
07:34:12.89 |
+27:25:38.6 |
HIP 36718 |
14.25 |
| 2026-07-31 00:00 |
07:34:44.18 |
+27:24:50.8 |
HIP 36718 |
21.22 |
| 2026-07-31 12:00 |
07:35:15.45 |
+27:24:02.8 |
HIP 36718 |
28.20 |
| 2026-08-01 00:00 |
07:35:46.69 |
+27:23:14.8 |
HIP 36962 |
29.55 |
| 2026-08-01 12:00 |
07:36:17.91 |
+27:22:26.6 |
HIP 36962 |
29.12 |
| 2026-08-02 00:00 |
07:36:49.10 |
+27:21:38.3 |
HIP 37131 |
26.06 |
| 2026-08-02 12:00 |
07:37:20.27 |
+27:20:49.9 |
HIP 37131 |
24.24 |
| 2026-08-03 00:00 |
07:37:51.40 |
+27:20:01.4 |
HIP 37131 |
24.34 |
| 2026-08-03 12:00 |
07:38:22.51 |
+27:19:12.8 |
HIP 37131 |
26.35 |
| 2026-08-04 00:00 |
07:38:53.59 |
+27:18:24.1 |
HIP 37131 |
29.87 |
| 2026-08-04 12:00 |
07:39:24.64 |
+27:17:35.3 |
HIP 37195 |
32.85 |
| 2026-08-05 00:00 |
07:39:55.66 |
+27:16:46.4 |
HIP 37337 |
33.46 |
| 2026-08-05 12:00 |
07:40:26.65 |
+27:15:57.4 |
HIP 37337 |
33.47 |
| 2026-08-06 00:00 |
07:40:57.60 |
+27:15:08.4 |
HIP 37337 |
34.89 |
| 2026-08-06 12:00 |
07:41:28.53 |
+27:14:19.2 |
HIP 37337 |
37.55 |
| 2026-08-07 00:00 |
07:41:59.42 |
+27:13:30.0 |
HIP 37337 |
41.22 |
| 2026-08-07 12:00 |
07:42:30.28 |
+27:12:40.7 |
HIP 37642 |
39.22 |
| 2026-08-08 00:00 |
07:43:01.10 |
+27:11:51.3 |
HIP 37642 |
36.67 |
| 2026-08-08 12:00 |
07:43:31.89 |
+27:11:01.8 |
HIP 37642 |
35.32 |
| 2026-08-09 00:00 |
07:44:02.64 |
+27:10:12.3 |
HIP 37642 |
35.29 |
| 2026-08-09 12:00 |
07:44:33.36 |
+27:09:22.8 |
HIP 37886 |
31.36 |
| 2026-08-10 00:00 |
07:45:04.03 |
+27:08:33.1 |
HIP 37886 |
27.30 |
| 2026-08-10 12:00 |
07:45:34.67 |
+27:07:43.5 |
HIP 37886 |
24.53 |
| 2026-08-11 00:00 |
07:46:05.27 |
+27:06:53.7 |
HIP 37886 |
23.52 |
| 2026-08-11 12:00 |
07:46:35.83 |
+27:06:04.0 |
HIP 37886 |
24.47 |
| 2026-08-12 00:00 |
07:47:06.35 |
+27:05:14.2 |
HIP 37886 |
27.17 |
| 2026-08-12 12:00 |
07:47:36.83 |
+27:04:24.4 |
HIP 37886 |
31.16 |
| 2026-08-13 00:00 |
07:48:07.26 |
+27:03:34.5 |
HIP 38228 |
30.11 |
| 2026-08-13 12:00 |
07:48:37.65 |
+27:02:44.6 |
HIP 38228 |
25.67 |
| 2026-08-14 00:00 |
07:49:07.99 |
+27:01:54.7 |
HIP 38228 |
22.47 |
| 2026-08-14 12:00 |
07:49:38.30 |
+27:01:04.8 |
HIP 38228 |
21.05 |
| 2026-08-15 00:00 |
07:50:08.55 |
+27:00:14.9 |
HIP 38228 |
21.75 |
| 2026-08-15 12:00 |
07:50:38.76 |
+26:59:24.9 |
HIP 38228 |
24.40 |
| 2026-08-16 00:00 |
07:51:08.92 |
+26:58:35.0 |
HIP 38228 |
28.43 |
| 2026-08-16 12:00 |
07:51:39.03 |
+26:57:45.1 |
HIP 38538 |
27.38 |
| 2026-08-17 00:00 |
07:52:09.09 |
+26:56:55.2 |
HIP 38538 |
21.09 |
| 2026-08-17 12:00 |
07:52:39.11 |
+26:56:05.2 |
HIP 38538 |
15.19 |
| 2026-08-18 00:00 |
07:53:09.07 |
+26:55:15.4 |
HIP 38538 |
10.39 |
| 2026-08-18 12:00 |
07:53:38.98 |
+26:54:25.5 |
HIP 38538 |
8.72 |
| 2026-08-19 00:00 |
07:54:08.84 |
+26:53:35.6 |
HIP 38538 |
11.58 |