| Parameter |
Value |
| Designation |
220P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-12-14T23:49:10.971840Z |
| Orbit solution date (soln_date, UTC) |
2026-05-05T09:12:21Z |
| Obs used |
499 |
| NEO |
- |
| M1 |
15.500 |
| K1 |
11.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-04-19.0000000 |
| e |
0.50191261 |
| q (au) |
1.550836 |
| a (au) |
3.113582 |
| i (deg) |
8.129976 |
| Ω (om, deg) |
150.126070 |
| ω (w, deg) |
180.755611 |
| M (ma, deg) |
153.564650 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-05-12 00:00 |
23:03:42.55 |
-03:17:28.4 |
HIP 113956 |
18.60 |
| 2026-05-12 12:00 |
23:05:05.87 |
-03:10:53.1 |
HIP 113956 |
19.96 |
| 2026-05-13 00:00 |
23:06:29.16 |
-03:04:17.9 |
HIP 113956 |
37.44 |
| 2026-05-13 12:00 |
23:07:52.43 |
-02:57:42.7 |
HIP 114313 |
30.46 |
| 2026-05-14 00:00 |
23:09:15.67 |
-02:51:07.7 |
HIP 114313 |
18.33 |
| 2026-05-14 12:00 |
23:10:38.90 |
-02:44:32.7 |
HIP 114510 |
25.96 |
| 2026-05-15 00:00 |
23:12:02.10 |
-02:37:57.9 |
HIP 114510 |
28.76 |
| 2026-05-15 12:00 |
23:13:25.27 |
-02:31:23.2 |
HIP 114700 |
12.27 |
| 2026-05-16 00:00 |
23:14:48.41 |
-02:24:48.8 |
HIP 114700 |
16.93 |
| 2026-05-16 12:00 |
23:16:11.53 |
-02:18:14.6 |
HIP 114700 |
37.03 |
| 2026-05-17 00:00 |
23:17:34.62 |
-02:11:40.7 |
HIP 115074 |
22.16 |
| 2026-05-17 12:00 |
23:18:57.68 |
-02:05:07.1 |
HIP 115091 |
10.65 |
| 2026-05-18 00:00 |
23:20:20.71 |
-01:58:33.8 |
HIP 115091 |
25.60 |
| 2026-05-18 12:00 |
23:21:43.70 |
-01:52:00.9 |
HIP 115302 |
18.21 |
| 2026-05-19 00:00 |
23:23:06.66 |
-01:45:28.4 |
HIP 115572 |
23.06 |
| 2026-05-19 12:00 |
23:24:29.59 |
-01:38:56.3 |
HIP 115572 |
6.00 |
| 2026-05-20 00:00 |
23:25:52.49 |
-01:32:24.6 |
HIP 115572 |
22.00 |
| 2026-05-20 12:00 |
23:27:15.34 |
-01:25:53.4 |
HIP 115752 |
9.09 |
| 2026-05-21 00:00 |
23:28:38.17 |
-01:19:22.7 |
HIP 115909 |
10.68 |
| 2026-05-21 12:00 |
23:30:00.95 |
-01:12:52.6 |
HIP 115951 |
13.18 |
| 2026-05-22 00:00 |
23:31:23.70 |
-01:06:23.0 |
HIP 116146 |
8.55 |
| 2026-05-22 12:00 |
23:32:46.41 |
-00:59:54.0 |
HIP 116209 |
9.34 |
| 2026-05-23 00:00 |
23:34:09.08 |
-00:53:25.6 |
HIP 116209 |
20.77 |
| 2026-05-23 12:00 |
23:35:31.71 |
-00:46:57.8 |
HIP 116320 |
30.16 |
| 2026-05-24 00:00 |
23:36:54.30 |
-00:40:30.7 |
HIP 116643 |
23.46 |
| 2026-05-24 12:00 |
23:38:16.85 |
-00:34:04.3 |
HIP 116643 |
18.05 |
| 2026-05-25 00:00 |
23:39:39.35 |
-00:27:38.6 |
HIP 116826 |
16.48 |
| 2026-05-25 12:00 |
23:41:01.82 |
-00:21:13.6 |
HIP 116826 |
5.12 |
| 2026-05-26 00:00 |
23:42:24.24 |
-00:14:49.5 |
HIP 117016 |
14.48 |
| 2026-05-26 12:00 |
23:43:46.62 |
-00:08:26.1 |
HIP 117016 |
7.25 |
| 2026-05-27 00:00 |
23:45:08.95 |
-00:02:03.5 |
HIP 117215 |
21.90 |
| 2026-05-27 12:00 |
23:46:31.23 |
+00:04:18.3 |
HIP 117215 |
13.82 |
| 2026-05-28 00:00 |
23:47:53.47 |
+00:10:39.1 |
HIP 117457 |
22.44 |
| 2026-05-28 12:00 |
23:49:15.66 |
+00:16:59.1 |
HIP 117457 |
10.30 |
| 2026-05-29 00:00 |
23:50:37.81 |
+00:23:18.1 |
HIP 117457 |
25.16 |
| 2026-05-29 12:00 |
23:51:59.90 |
+00:29:36.2 |
HIP 117832 |
28.73 |
| 2026-05-30 00:00 |
23:53:21.94 |
+00:35:53.3 |
HIP 117832 |
7.55 |
| 2026-05-30 12:00 |
23:54:43.94 |
+00:42:09.4 |
HIP 117960 |
13.00 |
| 2026-05-31 00:00 |
23:56:05.88 |
+00:48:24.4 |
HIP 117960 |
10.02 |
| 2026-05-31 12:00 |
23:57:27.76 |
+00:54:38.4 |
HIP 118035 |
24.61 |
| 2026-06-01 00:00 |
23:58:49.59 |
+01:00:51.3 |
HIP 1 |
18.21 |
| 2026-06-01 12:00 |
00:00:11.37 |
+01:07:03.1 |
HIP 1 |
3.27 |
| 2026-06-02 00:00 |
00:01:33.09 |
+01:13:13.7 |
HIP 51 |
17.34 |