442P/McNaught
| Parameter |
Value |
| Designation |
442P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-08-20T19:07:02.740800Z |
| Orbit solution date (soln_date, UTC) |
2024-07-07T00:42:22Z |
| Obs used |
452 |
| NEO |
- |
| M1 |
10.500 |
| K1 |
19.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-08-20.0000000 |
| e |
0.53159899 |
| q (au) |
2.328281 |
| a (au) |
4.970701 |
| i (deg) |
6.053247 |
| Ω (om, deg) |
32.033725 |
| ω (w, deg) |
310.972640 |
| M (ma, deg) |
229.993643 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.717 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.717 |
| n |
2.000 |
| gf |
0.983 |
| gb |
-0.900 |
| k |
0.999 |
| δ90 |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
09:27:42.71 |
+22:10:35.9 |
HIP 46276 |
35.61 |
| 2026-02-03 12:00 |
09:27:27.38 |
+22:11:45.9 |
HIP 46276 |
32.58 |
| 2026-02-04 00:00 |
09:27:12.04 |
+22:12:55.5 |
HIP 46276 |
29.71 |
| 2026-02-04 12:00 |
09:26:56.69 |
+22:14:04.8 |
HIP 46276 |
27.06 |
| 2026-02-05 00:00 |
09:26:41.32 |
+22:15:13.6 |
HIP 46276 |
24.69 |
| 2026-02-05 12:00 |
09:26:25.94 |
+22:16:22.1 |
HIP 46276 |
22.70 |
| 2026-02-06 00:00 |
09:26:10.55 |
+22:17:30.2 |
HIP 46276 |
21.20 |
| 2026-02-06 12:00 |
09:25:55.15 |
+22:18:37.8 |
HIP 46240 |
19.70 |
| 2026-02-07 00:00 |
09:25:39.74 |
+22:19:45.1 |
HIP 46240 |
18.19 |
| 2026-02-07 12:00 |
09:25:24.34 |
+22:20:51.9 |
HIP 46240 |
17.37 |
| 2026-02-08 00:00 |
09:25:08.93 |
+22:21:58.3 |
HIP 46240 |
17.34 |
| 2026-02-08 12:00 |
09:24:53.53 |
+22:23:04.2 |
HIP 46240 |
18.09 |
| 2026-02-09 00:00 |
09:24:38.13 |
+22:24:09.6 |
HIP 46240 |
19.55 |
| 2026-02-09 12:00 |
09:24:22.74 |
+22:25:14.6 |
HIP 46018 |
18.94 |
| 2026-02-10 00:00 |
09:24:07.35 |
+22:26:19.1 |
HIP 46018 |
16.18 |
| 2026-02-10 12:00 |
09:23:51.98 |
+22:27:23.2 |
HIP 46018 |
13.87 |
| 2026-02-11 00:00 |
09:23:36.62 |
+22:28:26.7 |
HIP 46018 |
12.26 |
| 2026-02-11 12:00 |
09:23:21.27 |
+22:29:29.7 |
HIP 46018 |
11.65 |
| 2026-02-12 00:00 |
09:23:05.94 |
+22:30:32.2 |
HIP 45954 |
10.81 |
| 2026-02-12 12:00 |
09:22:50.64 |
+22:31:34.2 |
HIP 45954 |
7.17 |
| 2026-02-13 00:00 |
09:22:35.35 |
+22:32:35.6 |
HIP 45954 |
3.62 |
| 2026-02-13 12:00 |
09:22:20.09 |
+22:33:36.5 |
HIP 45954 |
1.34 |
| 2026-02-14 00:00 |
09:22:04.86 |
+22:34:36.9 |
HIP 45954 |
4.16 |
| 2026-02-14 12:00 |
09:21:49.65 |
+22:35:36.7 |
HIP 45954 |
7.70 |
| 2026-02-15 00:00 |
09:21:34.48 |
+22:36:35.9 |
HIP 45907 |
9.44 |
| 2026-02-15 12:00 |
09:21:19.34 |
+22:37:34.5 |
HIP 45830 |
9.07 |
| 2026-02-16 00:00 |
09:21:04.24 |
+22:38:32.6 |
HIP 45830 |
5.50 |
| 2026-02-16 12:00 |
09:20:49.18 |
+22:39:30.0 |
HIP 45830 |
2.10 |
| 2026-02-17 00:00 |
09:20:34.16 |
+22:40:26.9 |
HIP 45830 |
2.13 |
| 2026-02-17 12:00 |
09:20:19.18 |
+22:41:23.2 |
HIP 45830 |
5.51 |
| 2026-02-18 00:00 |
09:20:04.24 |
+22:42:18.8 |
HIP 45830 |
9.03 |
| 2026-02-18 12:00 |
09:19:49.35 |
+22:43:13.8 |
HIP 45830 |
12.56 |
| 2026-02-19 00:00 |
09:19:34.52 |
+22:44:08.2 |
HIP 45830 |
16.09 |
| 2026-02-19 12:00 |
09:19:19.73 |
+22:45:01.9 |
HIP 45830 |
19.61 |
| 2026-02-20 00:00 |
09:19:05.00 |
+22:45:55.0 |
HIP 45830 |
23.11 |
| 2026-02-20 12:00 |
09:18:50.33 |
+22:46:47.5 |
HIP 45606 |
23.31 |
| 2026-02-21 00:00 |
09:18:35.71 |
+22:47:39.3 |
HIP 45606 |
20.60 |
| 2026-02-21 12:00 |
09:18:21.16 |
+22:48:30.4 |
HIP 45606 |
18.16 |
| 2026-02-22 00:00 |
09:18:06.66 |
+22:49:20.8 |
HIP 45606 |
16.12 |
| 2026-02-22 12:00 |
09:17:52.24 |
+22:50:10.6 |
HIP 45606 |
14.63 |
| 2026-02-23 00:00 |
09:17:37.88 |
+22:50:59.7 |
HIP 45606 |
13.85 |
| 2026-02-23 12:00 |
09:17:23.58 |
+22:51:48.1 |
HIP 45606 |
13.89 |
| 2026-02-24 00:00 |
09:17:09.36 |
+22:52:35.8 |
HIP 45606 |
14.73 |