| 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) |
| 2026-03-26 00:00 |
13:10:11.39 |
+04:39:15.7 |
HIP 64265 |
21.38 |
| 2026-03-26 12:00 |
13:09:54.70 |
+04:41:44.1 |
HIP 64265 |
19.81 |
| 2026-03-27 00:00 |
13:09:37.93 |
+04:44:12.1 |
HIP 64265 |
19.37 |
| 2026-03-27 12:00 |
13:09:21.09 |
+04:46:39.9 |
HIP 64265 |
20.14 |
| 2026-03-28 00:00 |
13:09:04.18 |
+04:49:07.2 |
HIP 64265 |
22.00 |
| 2026-03-28 12:00 |
13:08:47.20 |
+04:51:34.1 |
HIP 64150 |
20.99 |
| 2026-03-29 00:00 |
13:08:30.16 |
+04:54:00.6 |
HIP 64150 |
19.23 |
| 2026-03-29 12:00 |
13:08:13.05 |
+04:56:26.6 |
HIP 64150 |
18.66 |
| 2026-03-30 00:00 |
13:07:55.89 |
+04:58:52.1 |
HIP 64150 |
19.36 |
| 2026-03-30 12:00 |
13:07:38.67 |
+05:01:17.2 |
HIP 64150 |
21.23 |
| 2026-03-31 00:00 |
13:07:21.39 |
+05:03:41.7 |
HIP 64150 |
23.99 |
| 2026-03-31 12:00 |
13:07:04.06 |
+05:06:05.7 |
HIP 64150 |
27.39 |
| 2026-04-01 00:00 |
13:06:46.69 |
+05:08:29.1 |
HIP 64150 |
31.21 |
| 2026-04-01 12:00 |
13:06:29.27 |
+05:10:51.9 |
HIP 64150 |
35.32 |
| 2026-04-02 00:00 |
13:06:11.81 |
+05:13:14.1 |
HIP 63756 |
31.67 |
| 2026-04-02 12:00 |
13:05:54.32 |
+05:15:35.7 |
HIP 63756 |
27.59 |
| 2026-04-03 00:00 |
13:05:36.78 |
+05:17:56.6 |
HIP 63756 |
23.83 |
| 2026-04-03 12:00 |
13:05:19.22 |
+05:20:16.8 |
HIP 63756 |
20.56 |
| 2026-04-04 00:00 |
13:05:01.62 |
+05:22:36.4 |
HIP 63756 |
18.08 |
| 2026-04-04 12:00 |
13:04:44.00 |
+05:24:55.2 |
HIP 63756 |
16.72 |
| 2026-04-05 00:00 |
13:04:26.35 |
+05:27:13.3 |
HIP 63756 |
16.76 |
| 2026-04-05 12:00 |
13:04:08.69 |
+05:29:30.6 |
HIP 63756 |
18.20 |
| 2026-04-06 00:00 |
13:03:51.00 |
+05:31:47.2 |
HIP 63756 |
20.74 |
| 2026-04-06 12:00 |
13:03:33.31 |
+05:34:02.9 |
HIP 63756 |
24.03 |
| 2026-04-07 00:00 |
13:03:15.60 |
+05:36:17.8 |
HIP 63663 |
21.79 |
| 2026-04-07 12:00 |
13:02:57.88 |
+05:38:31.9 |
HIP 63663 |
18.82 |
| 2026-04-08 00:00 |
13:02:40.16 |
+05:40:45.1 |
HIP 63663 |
16.82 |
| 2026-04-08 12:00 |
13:02:22.44 |
+05:42:57.4 |
HIP 63663 |
16.14 |
| 2026-04-09 00:00 |
13:02:04.72 |
+05:45:08.8 |
HIP 63663 |
16.95 |
| 2026-04-09 12:00 |
13:01:47.00 |
+05:47:19.2 |
HIP 63663 |
19.04 |
| 2026-04-10 00:00 |
13:01:29.29 |
+05:49:28.7 |
HIP 63663 |
22.06 |
| 2026-04-10 12:00 |
13:01:11.59 |
+05:51:37.3 |
HIP 63454 |
17.62 |
| 2026-04-11 00:00 |
13:00:53.91 |
+05:53:44.8 |
HIP 63454 |
12.74 |
| 2026-04-11 12:00 |
13:00:36.24 |
+05:55:51.4 |
HIP 63454 |
7.87 |
| 2026-04-12 00:00 |
13:00:18.59 |
+05:57:56.9 |
HIP 63454 |
3.02 |
| 2026-04-12 12:00 |
13:00:00.97 |
+06:00:01.3 |
HIP 63454 |
1.88 |
| 2026-04-13 00:00 |
12:59:43.37 |
+06:02:04.7 |
HIP 63454 |
6.69 |
| 2026-04-13 12:00 |
12:59:25.81 |
+06:04:07.0 |
HIP 63454 |
11.51 |
| 2026-04-14 00:00 |
12:59:08.27 |
+06:06:08.2 |
HIP 63454 |
16.31 |
| 2026-04-14 12:00 |
12:58:50.78 |
+06:08:08.2 |
HIP 63454 |
21.10 |
| 2026-04-15 00:00 |
12:58:33.32 |
+06:10:07.1 |
HIP 63386 |
23.35 |
| 2026-04-15 12:00 |
12:58:15.91 |
+06:12:04.9 |
HIP 63383 |
24.24 |
| 2026-04-16 00:00 |
12:57:58.54 |
+06:14:01.4 |
HIP 63383 |
25.95 |