| Parameter |
Value |
| Designation |
220P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-12-10T19:12:44.254080Z |
| Orbit solution date (soln_date, UTC) |
2026-07-28T14:12:24Z |
| Obs used |
1004 |
| NEO |
- |
| M1 |
8.800 |
| K1 |
31.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-05-28.0000000 |
| e |
0.50165326 |
| q (au) |
1.552098 |
| a (au) |
3.114494 |
| i (deg) |
8.128033 |
| Ω (om, deg) |
150.112745 |
| ω (w, deg) |
180.580215 |
| M (ma, deg) |
259.080003 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.420 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.420 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
02:22:58.97 |
+09:10:00.7 |
HIP 11211 |
21.01 |
| 2026-07-29 12:00 |
02:24:01.10 |
+09:11:32.9 |
HIP 11211 |
7.03 |
| 2026-07-30 00:00 |
02:25:02.90 |
+09:13:02.0 |
HIP 11211 |
11.45 |
| 2026-07-30 12:00 |
02:26:04.39 |
+09:14:28.0 |
HIP 11211 |
26.05 |
| 2026-07-31 00:00 |
02:27:05.55 |
+09:15:50.8 |
HIP 11314 |
39.10 |
| 2026-07-31 12:00 |
02:28:06.38 |
+09:17:10.4 |
HIP 11603 |
27.61 |
| 2026-08-01 00:00 |
02:29:06.88 |
+09:18:26.9 |
HIP 11603 |
17.01 |
| 2026-08-01 12:00 |
02:30:07.05 |
+09:19:40.2 |
HIP 11603 |
16.27 |
| 2026-08-02 00:00 |
02:31:06.88 |
+09:20:50.4 |
HIP 11793 |
25.46 |
| 2026-08-02 12:00 |
02:32:06.37 |
+09:21:57.4 |
HIP 11793 |
21.12 |
| 2026-08-03 00:00 |
02:33:05.51 |
+09:23:01.3 |
HIP 11793 |
25.93 |
| 2026-08-03 12:00 |
02:34:04.31 |
+09:24:02.0 |
HIP 11793 |
36.33 |
| 2026-08-04 00:00 |
02:35:02.75 |
+09:24:59.5 |
HIP 12227 |
36.24 |
| 2026-08-04 12:00 |
02:36:00.83 |
+09:25:53.8 |
HIP 12227 |
22.27 |
| 2026-08-05 00:00 |
02:36:58.56 |
+09:26:45.0 |
HIP 12227 |
9.60 |
| 2026-08-05 12:00 |
02:37:55.92 |
+09:27:33.0 |
HIP 12227 |
9.72 |
| 2026-08-06 00:00 |
02:38:52.92 |
+09:28:17.8 |
HIP 12227 |
22.24 |
| 2026-08-06 12:00 |
02:39:49.54 |
+09:28:59.4 |
HIP 12529 |
26.91 |
| 2026-08-07 00:00 |
02:40:45.79 |
+09:29:37.8 |
HIP 12529 |
17.92 |
| 2026-08-07 12:00 |
02:41:41.66 |
+09:30:13.0 |
HIP 12529 |
17.43 |
| 2026-08-08 00:00 |
02:42:37.15 |
+09:30:45.1 |
HIP 12529 |
25.77 |
| 2026-08-08 12:00 |
02:43:32.25 |
+09:31:13.9 |
HIP 12794 |
21.85 |
| 2026-08-09 00:00 |
02:44:26.96 |
+09:31:39.6 |
HIP 12794 |
17.86 |
| 2026-08-09 12:00 |
02:45:21.27 |
+09:32:02.1 |
HIP 12853 |
14.24 |
| 2026-08-10 00:00 |
02:46:15.19 |
+09:32:21.4 |
HIP 12853 |
20.22 |
| 2026-08-10 12:00 |
02:47:08.70 |
+09:32:37.5 |
HIP 13018 |
14.59 |
| 2026-08-11 00:00 |
02:48:01.80 |
+09:32:50.4 |
HIP 13018 |
17.26 |
| 2026-08-11 12:00 |
02:48:54.49 |
+09:33:00.2 |
HIP 13018 |
26.84 |
| 2026-08-12 00:00 |
02:49:46.77 |
+09:33:06.8 |
HIP 13199 |
36.76 |
| 2026-08-12 12:00 |
02:50:38.63 |
+09:33:10.2 |
HIP 13199 |
38.52 |
| 2026-08-13 00:00 |
02:51:30.07 |
+09:33:10.4 |
HIP 13427 |
31.35 |
| 2026-08-13 12:00 |
02:52:21.08 |
+09:33:07.6 |
HIP 13495 |
24.67 |
| 2026-08-14 00:00 |
02:53:11.66 |
+09:33:01.5 |
HIP 13495 |
15.43 |
| 2026-08-14 12:00 |
02:54:01.82 |
+09:32:52.4 |
HIP 13495 |
13.29 |
| 2026-08-15 00:00 |
02:54:51.53 |
+09:32:40.1 |
HIP 13543 |
15.17 |
| 2026-08-15 12:00 |
02:55:40.81 |
+09:32:24.7 |
HIP 13690 |
17.20 |
| 2026-08-16 00:00 |
02:56:29.64 |
+09:32:06.2 |
HIP 13690 |
14.28 |
| 2026-08-16 12:00 |
02:57:18.03 |
+09:31:44.6 |
HIP 13690 |
19.94 |
| 2026-08-17 00:00 |
02:58:05.98 |
+09:31:19.9 |
HIP 13950 |
24.31 |
| 2026-08-17 12:00 |
02:58:53.46 |
+09:30:52.1 |
HIP 13950 |
13.71 |
| 2026-08-18 00:00 |
02:59:40.50 |
+09:30:21.3 |
HIP 13950 |
7.77 |
| 2026-08-18 12:00 |
03:00:27.08 |
+09:29:47.4 |
HIP 13950 |
14.15 |
| 2026-08-19 00:00 |
03:01:13.19 |
+09:29:10.5 |
HIP 13950 |
24.50 |