| 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) |
| 2026-06-01 00:00 |
12:40:07.48 |
+07:26:44.6 |
HIP 61754 |
13.51 |
| 2026-06-01 12:00 |
12:40:03.95 |
+07:26:19.2 |
HIP 61754 |
13.06 |
| 2026-06-02 00:00 |
12:40:00.62 |
+07:25:52.4 |
HIP 61754 |
12.72 |
| 2026-06-02 12:00 |
12:39:57.49 |
+07:25:24.1 |
HIP 61754 |
12.50 |
| 2026-06-03 00:00 |
12:39:54.56 |
+07:24:54.3 |
HIP 61754 |
12.38 |
| 2026-06-03 12:00 |
12:39:51.83 |
+07:24:23.1 |
HIP 61754 |
12.38 |
| 2026-06-04 00:00 |
12:39:49.29 |
+07:23:50.4 |
HIP 61754 |
12.49 |
| 2026-06-04 12:00 |
12:39:46.96 |
+07:23:16.4 |
HIP 61754 |
12.69 |
| 2026-06-05 00:00 |
12:39:44.83 |
+07:22:40.9 |
HIP 61754 |
12.98 |
| 2026-06-05 12:00 |
12:39:42.89 |
+07:22:04.0 |
HIP 61754 |
13.35 |
| 2026-06-06 00:00 |
12:39:41.16 |
+07:21:25.7 |
HIP 61754 |
13.80 |
| 2026-06-06 12:00 |
12:39:39.62 |
+07:20:45.9 |
HIP 61754 |
14.31 |
| 2026-06-07 00:00 |
12:39:38.29 |
+07:20:04.8 |
HIP 61754 |
14.88 |
| 2026-06-07 12:00 |
12:39:37.15 |
+07:19:22.3 |
HIP 61754 |
15.50 |
| 2026-06-08 00:00 |
12:39:36.21 |
+07:18:38.4 |
HIP 61754 |
16.16 |
| 2026-06-08 12:00 |
12:39:35.48 |
+07:17:53.1 |
HIP 61754 |
16.86 |
| 2026-06-09 00:00 |
12:39:34.94 |
+07:17:06.5 |
HIP 61754 |
17.60 |
| 2026-06-09 12:00 |
12:39:34.60 |
+07:16:18.5 |
HIP 61754 |
18.38 |
| 2026-06-10 00:00 |
12:39:34.46 |
+07:15:29.1 |
HIP 61754 |
19.19 |
| 2026-06-10 12:00 |
12:39:34.52 |
+07:14:38.4 |
HIP 61754 |
20.02 |
| 2026-06-11 00:00 |
12:39:34.77 |
+07:13:46.4 |
HIP 61754 |
20.89 |
| 2026-06-11 12:00 |
12:39:35.23 |
+07:12:53.0 |
HIP 61667 |
21.13 |
| 2026-06-12 00:00 |
12:39:35.88 |
+07:11:58.3 |
HIP 61667 |
20.68 |
| 2026-06-12 12:00 |
12:39:36.73 |
+07:11:02.3 |
HIP 61667 |
20.29 |
| 2026-06-13 00:00 |
12:39:37.78 |
+07:10:04.9 |
HIP 61667 |
19.98 |
| 2026-06-13 12:00 |
12:39:39.03 |
+07:09:06.3 |
HIP 61667 |
19.74 |
| 2026-06-14 00:00 |
12:39:40.48 |
+07:08:06.3 |
HIP 61667 |
19.58 |
| 2026-06-14 12:00 |
12:39:42.12 |
+07:07:05.1 |
HIP 61667 |
19.52 |
| 2026-06-15 00:00 |
12:39:43.96 |
+07:06:02.6 |
HIP 61667 |
19.56 |
| 2026-06-15 12:00 |
12:39:46.00 |
+07:04:58.8 |
HIP 61667 |
19.70 |
| 2026-06-16 00:00 |
12:39:48.23 |
+07:03:53.7 |
HIP 61667 |
19.95 |
| 2026-06-16 12:00 |
12:39:50.66 |
+07:02:47.4 |
HIP 61667 |
20.32 |
| 2026-06-17 00:00 |
12:39:53.28 |
+07:01:39.9 |
HIP 61667 |
20.81 |
| 2026-06-17 12:00 |
12:39:56.10 |
+07:00:31.1 |
HIP 61667 |
21.41 |
| 2026-06-18 00:00 |
12:39:59.12 |
+06:59:21.1 |
HIP 61667 |
22.12 |
| 2026-06-18 12:00 |
12:40:02.32 |
+06:58:09.8 |
HIP 61667 |
22.95 |
| 2026-06-19 00:00 |
12:40:05.72 |
+06:56:57.4 |
HIP 61667 |
23.88 |
| 2026-06-19 12:00 |
12:40:09.32 |
+06:55:43.8 |
HIP 61667 |
24.92 |
| 2026-06-20 00:00 |
12:40:13.10 |
+06:54:29.0 |
HIP 61667 |
26.05 |
| 2026-06-20 12:00 |
12:40:17.08 |
+06:53:13.0 |
HIP 61968 |
25.31 |
| 2026-06-21 00:00 |
12:40:21.24 |
+06:51:55.8 |
HIP 61968 |
24.07 |
| 2026-06-21 12:00 |
12:40:25.60 |
+06:50:37.5 |
HIP 61968 |
22.84 |
| 2026-06-22 00:00 |
12:40:30.14 |
+06:49:18.0 |
HIP 61968 |
21.62 |