| Parameter |
Value |
| Designation |
338P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2016-11-21T23:54:59.846400Z |
| Orbit solution date (soln_date, UTC) |
2025-02-13T09:13:12Z |
| Obs used |
882 |
| NEO |
- |
| M1 |
15.500 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-02-14.0000000 |
| e |
0.41033494 |
| q (au) |
2.301407 |
| a (au) |
3.902905 |
| i (deg) |
25.350404 |
| Ω (om, deg) |
9.805290 |
| ω (w, deg) |
4.508283 |
| M (ma, deg) |
57.394693 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.883 + 5.284\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.883 |
| n |
5.284 |
| gf |
0.999 |
| gb |
-0.937 |
| k |
1.000 |
| δ90 |
9.998 |
| 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) |
| 2026-06-01 00:00 |
09:29:57.52 |
+32:15:31.6 |
HIP 46590 |
13.10 |
| 2026-06-01 12:00 |
09:30:17.77 |
+32:11:41.4 |
HIP 46590 |
9.73 |
| 2026-06-02 00:00 |
09:30:38.14 |
+32:07:51.3 |
HIP 46590 |
9.19 |
| 2026-06-02 12:00 |
09:30:58.62 |
+32:04:01.1 |
HIP 46590 |
11.89 |
| 2026-06-03 00:00 |
09:31:19.22 |
+32:00:11.1 |
HIP 46809 |
14.60 |
| 2026-06-03 12:00 |
09:31:39.94 |
+31:56:21.0 |
HIP 46809 |
8.92 |
| 2026-06-04 00:00 |
09:32:00.77 |
+31:52:31.1 |
HIP 46809 |
3.71 |
| 2026-06-04 12:00 |
09:32:21.70 |
+31:48:41.1 |
HIP 46809 |
4.05 |
| 2026-06-05 00:00 |
09:32:42.75 |
+31:44:51.2 |
HIP 46809 |
9.40 |
| 2026-06-05 12:00 |
09:33:03.91 |
+31:41:01.4 |
HIP 46809 |
15.17 |
| 2026-06-06 00:00 |
09:33:25.18 |
+31:37:11.6 |
HIP 46809 |
21.03 |
| 2026-06-06 12:00 |
09:33:46.56 |
+31:33:21.9 |
HIP 46809 |
26.94 |
| 2026-06-07 00:00 |
09:34:08.04 |
+31:29:32.2 |
HIP 47064 |
30.06 |
| 2026-06-07 12:00 |
09:34:29.62 |
+31:25:42.5 |
HIP 47064 |
24.34 |
| 2026-06-08 00:00 |
09:34:51.31 |
+31:21:52.9 |
HIP 47064 |
18.77 |
| 2026-06-08 12:00 |
09:35:13.10 |
+31:18:03.4 |
HIP 47064 |
13.56 |
| 2026-06-09 00:00 |
09:35:34.99 |
+31:14:13.9 |
HIP 47064 |
9.41 |
| 2026-06-09 12:00 |
09:35:56.99 |
+31:10:24.5 |
HIP 47064 |
8.16 |
| 2026-06-10 00:00 |
09:36:19.08 |
+31:06:35.1 |
HIP 47168 |
5.97 |
| 2026-06-10 12:00 |
09:36:41.27 |
+31:02:45.8 |
HIP 47168 |
6.96 |
| 2026-06-11 00:00 |
09:37:03.56 |
+30:58:56.5 |
HIP 47222 |
5.19 |
| 2026-06-11 12:00 |
09:37:25.94 |
+30:55:07.3 |
HIP 47222 |
2.32 |
| 2026-06-12 00:00 |
09:37:48.42 |
+30:51:18.2 |
HIP 47222 |
7.70 |
| 2026-06-12 12:00 |
09:38:11.00 |
+30:47:29.1 |
HIP 47324 |
5.61 |
| 2026-06-13 00:00 |
09:38:33.66 |
+30:43:40.1 |
HIP 47324 |
2.07 |
| 2026-06-13 12:00 |
09:38:56.42 |
+30:39:51.1 |
HIP 47324 |
7.34 |
| 2026-06-14 00:00 |
09:39:19.27 |
+30:36:02.2 |
HIP 47324 |
13.45 |
| 2026-06-14 12:00 |
09:39:42.21 |
+30:32:13.4 |
HIP 47361 |
18.22 |
| 2026-06-15 00:00 |
09:40:05.23 |
+30:28:24.7 |
HIP 47361 |
18.53 |
| 2026-06-15 12:00 |
09:40:28.34 |
+30:24:36.0 |
HIP 47361 |
20.83 |
| 2026-06-16 00:00 |
09:40:51.54 |
+30:20:47.4 |
HIP 47361 |
24.59 |
| 2026-06-16 12:00 |
09:41:14.83 |
+30:16:58.9 |
HIP 47636 |
21.96 |
| 2026-06-17 00:00 |
09:41:38.19 |
+30:13:10.4 |
HIP 47636 |
15.75 |
| 2026-06-17 12:00 |
09:42:01.64 |
+30:09:22.1 |
HIP 47636 |
9.66 |
| 2026-06-18 00:00 |
09:42:25.17 |
+30:05:33.8 |
HIP 47636 |
4.35 |
| 2026-06-18 12:00 |
09:42:48.78 |
+30:01:45.6 |
HIP 47636 |
5.01 |
| 2026-06-19 00:00 |
09:43:12.47 |
+29:57:57.5 |
HIP 47701 |
4.54 |
| 2026-06-19 12:00 |
09:43:36.24 |
+29:54:09.5 |
HIP 47701 |
4.37 |
| 2026-06-20 00:00 |
09:44:00.08 |
+29:50:21.5 |
HIP 47701 |
9.99 |
| 2026-06-20 12:00 |
09:44:24.00 |
+29:46:33.7 |
HIP 47701 |
16.22 |
| 2026-06-21 00:00 |
09:44:47.99 |
+29:42:46.0 |
HIP 47701 |
22.57 |
| 2026-06-21 12:00 |
09:45:12.05 |
+29:38:58.3 |
HIP 47701 |
28.98 |
| 2026-06-22 00:00 |
09:45:36.19 |
+29:35:10.8 |
HIP 48048 |
27.16 |