| Parameter |
Value |
| Designation |
431P/Scotti |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-09-09T08:10:57.241920Z |
| Orbit solution date (soln_date, UTC) |
2025-01-02T20:13:02Z |
| Obs used |
519 |
| NEO |
- |
| M1 |
12.000 |
| K1 |
19.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-08-07.0000000 |
| e |
0.48795756 |
| q (au) |
1.762569 |
| a (au) |
3.442232 |
| i (deg) |
22.671799 |
| Ω (om, deg) |
203.270091 |
| ω (w, deg) |
199.435229 |
| M (ma, deg) |
107.668137 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.900 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.900 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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 |
| 2021-09-02 |
2022-03-01 |
+12.0411 |
-3.322 |
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 |
16:11:14.30 |
-04:13:44.2 |
HIP 79316 |
14.39 |
| 2026-09-20 12:00 |
16:11:31.85 |
-04:15:31.4 |
HIP 79316 |
16.77 |
| 2026-09-21 00:00 |
16:11:49.55 |
-04:17:18.5 |
HIP 79463 |
17.20 |
| 2026-09-21 12:00 |
16:12:07.40 |
-04:19:05.5 |
HIP 79463 |
13.59 |
| 2026-09-22 00:00 |
16:12:25.40 |
-04:20:52.3 |
HIP 79463 |
10.89 |
| 2026-09-22 12:00 |
16:12:43.56 |
-04:22:39.1 |
HIP 79463 |
9.95 |
| 2026-09-23 00:00 |
16:13:01.85 |
-04:24:25.7 |
HIP 79463 |
11.26 |
| 2026-09-23 12:00 |
16:13:20.30 |
-04:26:12.1 |
HIP 79463 |
14.24 |
| 2026-09-24 00:00 |
16:13:38.89 |
-04:27:58.4 |
HIP 79463 |
18.11 |
| 2026-09-24 12:00 |
16:13:57.63 |
-04:29:44.5 |
HIP 79567 |
20.35 |
| 2026-09-25 00:00 |
16:14:16.51 |
-04:31:30.4 |
HIP 79567 |
22.14 |
| 2026-09-25 12:00 |
16:14:35.53 |
-04:33:16.2 |
HIP 79567 |
24.84 |
| 2026-09-26 00:00 |
16:14:54.70 |
-04:35:01.8 |
HIP 79681 |
22.49 |
| 2026-09-26 12:00 |
16:15:14.01 |
-04:36:47.1 |
HIP 79681 |
18.64 |
| 2026-09-27 00:00 |
16:15:33.46 |
-04:38:32.3 |
HIP 79681 |
15.53 |
| 2026-09-27 12:00 |
16:15:53.05 |
-04:40:17.3 |
HIP 79681 |
13.72 |
| 2026-09-28 00:00 |
16:16:12.78 |
-04:42:02.1 |
HIP 79681 |
13.78 |
| 2026-09-28 12:00 |
16:16:32.65 |
-04:43:46.7 |
HIP 79681 |
15.71 |
| 2026-09-29 00:00 |
16:16:52.65 |
-04:45:31.0 |
HIP 79681 |
18.97 |
| 2026-09-29 12:00 |
16:17:12.80 |
-04:47:15.1 |
HIP 79882 |
17.51 |
| 2026-09-30 00:00 |
16:17:33.08 |
-04:48:59.0 |
HIP 79882 |
13.69 |
| 2026-09-30 12:00 |
16:17:53.50 |
-04:50:42.7 |
HIP 79882 |
11.18 |
| 2026-10-01 00:00 |
16:18:14.05 |
-04:52:26.0 |
HIP 79882 |
10.95 |
| 2026-10-01 12:00 |
16:18:34.74 |
-04:54:09.2 |
HIP 79882 |
13.18 |
| 2026-10-02 00:00 |
16:18:55.57 |
-04:55:52.1 |
HIP 79882 |
16.93 |
| 2026-10-02 12:00 |
16:19:16.52 |
-04:57:34.7 |
HIP 79882 |
21.46 |
| 2026-10-03 00:00 |
16:19:37.61 |
-04:59:17.0 |
HIP 79882 |
26.37 |
| 2026-10-03 12:00 |
16:19:58.84 |
-05:00:59.1 |
HIP 80037 |
27.84 |
| 2026-10-04 00:00 |
16:20:20.19 |
-05:02:40.9 |
HIP 80037 |
29.23 |
| 2026-10-04 12:00 |
16:20:41.68 |
-05:04:22.3 |
HIP 80037 |
31.56 |
| 2026-10-05 00:00 |
16:21:03.29 |
-05:06:03.5 |
HIP 80037 |
34.66 |
| 2026-10-05 12:00 |
16:21:25.04 |
-05:07:44.4 |
HIP 80191 |
35.43 |
| 2026-10-06 00:00 |
16:21:46.92 |
-05:09:25.0 |
HIP 80191 |
32.19 |
| 2026-10-06 12:00 |
16:22:08.92 |
-05:11:05.2 |
HIP 80191 |
29.70 |
| 2026-10-07 00:00 |
16:22:31.05 |
-05:12:45.1 |
HIP 80191 |
28.18 |
| 2026-10-07 12:00 |
16:22:53.31 |
-05:14:24.7 |
HIP 80191 |
27.81 |
| 2026-10-08 00:00 |
16:23:15.69 |
-05:16:03.9 |
HIP 80191 |
28.64 |
| 2026-10-08 12:00 |
16:23:38.20 |
-05:17:42.8 |
HIP 80191 |
30.60 |
| 2026-10-09 00:00 |
16:24:00.83 |
-05:19:21.3 |
HIP 80191 |
33.50 |
| 2026-10-09 12:00 |
16:24:23.59 |
-05:20:59.4 |
HIP 80191 |
37.14 |
| 2026-10-10 00:00 |
16:24:46.47 |
-05:22:37.2 |
HIP 80191 |
41.34 |
| 2026-10-10 12:00 |
16:25:09.47 |
-05:24:14.6 |
HIP 80494 |
42.71 |
| 2026-10-11 00:00 |
16:25:32.60 |
-05:25:51.6 |
HIP 80494 |
40.09 |