| Parameter |
Value |
| Designation |
284P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-09-14T05:45:32.915520Z |
| Orbit solution date (soln_date, UTC) |
2024-02-21T14:09:44Z |
| Obs used |
1370 |
| NEO |
- |
| M1 |
9.300 |
| K1 |
17.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-07-22.0000000 |
| e |
0.37568432 |
| q (au) |
2.292800 |
| a (au) |
3.672500 |
| i (deg) |
11.859915 |
| Ω (om, deg) |
144.293116 |
| ω (w, deg) |
202.773845 |
| M (ma, deg) |
198.916990 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.012 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.012 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.551 |
| k |
0.800 |
| 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 |
| 2020-04-17 |
2021-09-14 |
+3.2889 |
-0.825 |
| 2021-09-14 |
2024-02-04 |
-0.6016 |
-0.069 |
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 |
12:53:59.98 |
+04:27:52.2 |
HIP 62917 |
14.47 |
| 2026-07-29 12:00 |
12:54:16.59 |
+04:25:29.8 |
HIP 62917 |
14.44 |
| 2026-07-30 00:00 |
12:54:33.34 |
+04:23:06.8 |
HIP 62917 |
15.94 |
| 2026-07-30 12:00 |
12:54:50.22 |
+04:20:43.2 |
HIP 62917 |
18.62 |
| 2026-07-31 00:00 |
12:55:07.22 |
+04:18:19.2 |
HIP 62917 |
22.08 |
| 2026-07-31 12:00 |
12:55:24.36 |
+04:15:54.5 |
HIP 63209 |
25.00 |
| 2026-08-01 00:00 |
12:55:41.62 |
+04:13:29.4 |
HIP 63209 |
20.40 |
| 2026-08-01 12:00 |
12:55:59.01 |
+04:11:03.8 |
HIP 63209 |
15.97 |
| 2026-08-02 00:00 |
12:56:16.52 |
+04:08:37.6 |
HIP 63209 |
11.93 |
| 2026-08-02 12:00 |
12:56:34.16 |
+04:06:10.9 |
HIP 63209 |
8.91 |
| 2026-08-03 00:00 |
12:56:51.93 |
+04:03:43.7 |
HIP 63209 |
8.19 |
| 2026-08-03 12:00 |
12:57:09.82 |
+04:01:16.0 |
HIP 63209 |
10.31 |
| 2026-08-04 00:00 |
12:57:27.84 |
+03:58:47.8 |
HIP 63209 |
14.07 |
| 2026-08-04 12:00 |
12:57:45.97 |
+03:56:19.2 |
HIP 63209 |
18.52 |
| 2026-08-05 00:00 |
12:58:04.23 |
+03:53:50.0 |
HIP 63209 |
23.30 |
| 2026-08-05 12:00 |
12:58:22.62 |
+03:51:20.4 |
HIP 63209 |
28.24 |
| 2026-08-06 00:00 |
12:58:41.12 |
+03:48:50.3 |
HIP 63487 |
29.99 |
| 2026-08-06 12:00 |
12:58:59.74 |
+03:46:19.7 |
HIP 63487 |
24.72 |
| 2026-08-07 00:00 |
12:59:18.49 |
+03:43:48.7 |
HIP 63487 |
19.43 |
| 2026-08-07 12:00 |
12:59:37.35 |
+03:41:17.2 |
HIP 63487 |
14.12 |
| 2026-08-08 00:00 |
12:59:56.33 |
+03:38:45.3 |
HIP 63487 |
8.82 |
| 2026-08-08 12:00 |
13:00:15.44 |
+03:36:12.9 |
HIP 63487 |
3.69 |
| 2026-08-09 00:00 |
13:00:34.65 |
+03:33:40.2 |
HIP 63487 |
2.81 |
| 2026-08-09 12:00 |
13:00:53.99 |
+03:31:06.9 |
HIP 63487 |
7.84 |
| 2026-08-10 00:00 |
13:01:13.44 |
+03:28:33.3 |
HIP 63487 |
13.25 |
| 2026-08-10 12:00 |
13:01:33.01 |
+03:25:59.2 |
HIP 63487 |
18.73 |
| 2026-08-11 00:00 |
13:01:52.69 |
+03:23:24.7 |
HIP 63487 |
24.25 |
| 2026-08-11 12:00 |
13:02:12.49 |
+03:20:49.9 |
HIP 63487 |
29.82 |
| 2026-08-12 00:00 |
13:02:32.40 |
+03:18:14.6 |
HIP 63487 |
35.41 |
| 2026-08-12 12:00 |
13:02:52.42 |
+03:15:38.9 |
HIP 63487 |
41.03 |
| 2026-08-13 00:00 |
13:03:12.55 |
+03:13:02.9 |
HIP 63487 |
46.68 |
| 2026-08-13 12:00 |
13:03:32.80 |
+03:10:26.5 |
HIP 63944 |
49.79 |
| 2026-08-14 00:00 |
13:03:53.15 |
+03:07:49.7 |
HIP 63944 |
44.13 |
| 2026-08-14 12:00 |
13:04:13.62 |
+03:05:12.6 |
HIP 63944 |
38.47 |
| 2026-08-15 00:00 |
13:04:34.19 |
+03:02:35.1 |
HIP 63944 |
32.81 |
| 2026-08-15 12:00 |
13:04:54.87 |
+02:59:57.2 |
HIP 63944 |
27.16 |
| 2026-08-16 00:00 |
13:05:15.66 |
+02:57:19.1 |
HIP 63944 |
21.58 |
| 2026-08-16 12:00 |
13:05:36.56 |
+02:54:40.6 |
HIP 63944 |
16.14 |
| 2026-08-17 00:00 |
13:05:57.56 |
+02:52:01.7 |
HIP 63944 |
11.12 |
| 2026-08-17 12:00 |
13:06:18.67 |
+02:49:22.6 |
HIP 63944 |
7.45 |
| 2026-08-18 00:00 |
13:06:39.88 |
+02:46:43.1 |
HIP 63944 |
7.57 |
| 2026-08-18 12:00 |
13:07:01.19 |
+02:44:03.4 |
HIP 63944 |
11.39 |
| 2026-08-19 00:00 |
13:07:22.61 |
+02:41:23.3 |
HIP 63944 |
16.56 |