| Parameter |
Value |
| Designation |
66P/du Toit |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-05-20T11:15:17.081280Z |
| Orbit solution date (soln_date, UTC) |
2019-06-03T14:53:20Z |
| Obs used |
547 |
| NEO |
Yes |
| M1 |
15.700 |
| K1 |
7.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2014-10-31.0000000 |
| e |
0.78656817 |
| q (au) |
1.285451 |
| a (au) |
6.022773 |
| i (deg) |
18.668971 |
| Ω (om, deg) |
21.999851 |
| ω (w, deg) |
257.342734 |
| M (ma, deg) |
273.482032 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.128 + 5.614\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.128 |
| n |
5.614 |
| gf |
0.972 |
| gb |
-0.780 |
| k |
0.995 |
| δ90 |
9.986 |
| 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 |
| 2018-01-14 |
2018-05-20 |
+20.2694 |
-4.971 |
| 2018-05-21 |
2018-10-04 |
+19.3493 |
-5.821 |
| 2018-10-04 |
2018-11-10 |
-27.9513 |
+9.461 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
07:31:01.12 |
+39:55:01.4 |
HIP 36453 |
16.76 |
| 2026-09-20 12:00 |
07:31:08.54 |
+39:55:34.7 |
HIP 36443 |
17.77 |
| 2026-09-21 00:00 |
07:31:15.86 |
+39:56:08.3 |
HIP 36443 |
18.48 |
| 2026-09-21 12:00 |
07:31:23.08 |
+39:56:42.3 |
HIP 36443 |
19.27 |
| 2026-09-22 00:00 |
07:31:30.21 |
+39:57:16.6 |
HIP 36443 |
20.12 |
| 2026-09-22 12:00 |
07:31:37.25 |
+39:57:51.3 |
HIP 36443 |
21.02 |
| 2026-09-23 00:00 |
07:31:44.18 |
+39:58:26.4 |
HIP 36443 |
21.96 |
| 2026-09-23 12:00 |
07:31:51.02 |
+39:59:01.9 |
HIP 36443 |
22.93 |
| 2026-09-24 00:00 |
07:31:57.76 |
+39:59:37.7 |
HIP 36443 |
23.93 |
| 2026-09-24 12:00 |
07:32:04.40 |
+40:00:13.9 |
HIP 36443 |
24.95 |
| 2026-09-25 00:00 |
07:32:10.94 |
+40:00:50.5 |
HIP 36443 |
25.99 |
| 2026-09-25 12:00 |
07:32:17.38 |
+40:01:27.4 |
HIP 36443 |
27.04 |
| 2026-09-26 00:00 |
07:32:23.72 |
+40:02:04.7 |
HIP 36443 |
28.09 |
| 2026-09-26 12:00 |
07:32:29.96 |
+40:02:42.4 |
HIP 36443 |
29.15 |
| 2026-09-27 00:00 |
07:32:36.10 |
+40:03:20.5 |
HIP 36533 |
30.04 |
| 2026-09-27 12:00 |
07:32:42.13 |
+40:03:58.9 |
HIP 36533 |
30.30 |
| 2026-09-28 00:00 |
07:32:48.07 |
+40:04:37.6 |
HIP 36533 |
30.60 |
| 2026-09-28 12:00 |
07:32:53.90 |
+40:05:16.8 |
HIP 36533 |
30.93 |
| 2026-09-29 00:00 |
07:32:59.62 |
+40:05:56.2 |
HIP 36533 |
31.29 |
| 2026-09-29 12:00 |
07:33:05.25 |
+40:06:36.1 |
HIP 36533 |
31.68 |
| 2026-09-30 00:00 |
07:33:10.76 |
+40:07:16.3 |
HIP 36533 |
32.09 |
| 2026-09-30 12:00 |
07:33:16.18 |
+40:07:56.9 |
HIP 36906 |
32.03 |
| 2026-10-01 00:00 |
07:33:21.48 |
+40:08:37.8 |
HIP 36906 |
30.83 |
| 2026-10-01 12:00 |
07:33:26.68 |
+40:09:19.1 |
HIP 36906 |
29.65 |
| 2026-10-02 00:00 |
07:33:31.77 |
+40:10:00.8 |
HIP 36906 |
28.47 |
| 2026-10-02 12:00 |
07:33:36.76 |
+40:10:42.8 |
HIP 36906 |
27.30 |
| 2026-10-03 00:00 |
07:33:41.63 |
+40:11:25.1 |
HIP 36906 |
26.15 |
| 2026-10-03 12:00 |
07:33:46.40 |
+40:12:07.9 |
HIP 36906 |
25.01 |
| 2026-10-04 00:00 |
07:33:51.06 |
+40:12:50.9 |
HIP 36906 |
23.88 |
| 2026-10-04 12:00 |
07:33:55.60 |
+40:13:34.4 |
HIP 36906 |
22.76 |
| 2026-10-05 00:00 |
07:34:00.04 |
+40:14:18.1 |
HIP 36906 |
21.65 |
| 2026-10-05 12:00 |
07:34:04.36 |
+40:15:02.3 |
HIP 36906 |
20.55 |
| 2026-10-06 00:00 |
07:34:08.57 |
+40:15:46.7 |
HIP 36906 |
19.46 |
| 2026-10-06 12:00 |
07:34:12.67 |
+40:16:31.6 |
HIP 36906 |
18.39 |
| 2026-10-07 00:00 |
07:34:16.66 |
+40:17:16.7 |
HIP 36906 |
17.32 |
| 2026-10-07 12:00 |
07:34:20.53 |
+40:18:02.2 |
HIP 36906 |
16.26 |
| 2026-10-08 00:00 |
07:34:24.29 |
+40:18:48.1 |
HIP 36906 |
15.22 |
| 2026-10-08 12:00 |
07:34:27.93 |
+40:19:34.3 |
HIP 36906 |
14.18 |
| 2026-10-09 00:00 |
07:34:31.46 |
+40:20:20.8 |
HIP 36906 |
13.15 |
| 2026-10-09 12:00 |
07:34:34.87 |
+40:21:07.7 |
HIP 36906 |
12.14 |
| 2026-10-10 00:00 |
07:34:38.17 |
+40:21:54.9 |
HIP 36906 |
11.13 |
| 2026-10-10 12:00 |
07:34:41.35 |
+40:22:42.4 |
HIP 36906 |
10.14 |
| 2026-10-11 00:00 |
07:34:44.41 |
+40:23:30.2 |
HIP 36906 |
9.15 |