| Parameter |
Value |
| Designation |
508P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-01-15T03:13:20.297280Z |
| Orbit solution date (soln_date, UTC) |
2026-03-12T02:49:59Z |
| Obs used |
115 |
| NEO |
- |
| M1 |
14.400 |
| K1 |
23.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2005-05-03T17:19:54.624000Z |
| Discovery magnitude (MPC) |
17.60 T |
| Discovery observatory (MPC) |
E12 · Siding Spring Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-12-17.0000000 |
| e |
0.57045556 |
| q (au) |
1.533483 |
| a (au) |
3.570023 |
| i (deg) |
31.765073 |
| Ω (om, deg) |
268.821639 |
| ω (w, deg) |
339.031332 |
| M (ma, deg) |
195.746050 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.357 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.357 |
| n |
2.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
23:02:22.87 |
+19:26:43.3 |
HIP 113765 |
14.42 |
| 2026-03-26 12:00 |
23:03:07.94 |
+19:32:52.6 |
HIP 113765 |
13.86 |
| 2026-03-27 00:00 |
23:03:52.93 |
+19:39:01.8 |
HIP 113765 |
21.82 |
| 2026-03-27 12:00 |
23:04:37.82 |
+19:45:11.1 |
HIP 114096 |
28.41 |
| 2026-03-28 00:00 |
23:05:22.63 |
+19:51:20.4 |
HIP 114096 |
16.57 |
| 2026-03-28 12:00 |
23:06:07.36 |
+19:57:29.7 |
HIP 114096 |
6.39 |
| 2026-03-29 00:00 |
23:06:52.00 |
+20:03:38.9 |
HIP 114096 |
10.18 |
| 2026-03-29 12:00 |
23:07:36.55 |
+20:09:48.2 |
HIP 114282 |
19.51 |
| 2026-03-30 00:00 |
23:08:21.02 |
+20:15:57.4 |
HIP 114282 |
16.94 |
| 2026-03-30 12:00 |
23:09:05.40 |
+20:22:06.6 |
HIP 114282 |
22.06 |
| 2026-03-31 00:00 |
23:09:49.70 |
+20:28:15.8 |
HIP 114505 |
23.76 |
| 2026-03-31 12:00 |
23:10:33.91 |
+20:34:24.9 |
HIP 114505 |
12.79 |
| 2026-04-01 00:00 |
23:11:18.03 |
+20:40:34.1 |
HIP 114505 |
7.27 |
| 2026-04-01 12:00 |
23:12:02.07 |
+20:46:43.2 |
HIP 114505 |
15.19 |
| 2026-04-02 00:00 |
23:12:46.02 |
+20:52:52.2 |
HIP 114505 |
26.37 |
| 2026-04-02 12:00 |
23:13:29.88 |
+20:59:01.3 |
HIP 114759 |
18.37 |
| 2026-04-03 00:00 |
23:14:13.66 |
+21:05:10.3 |
HIP 114759 |
13.94 |
| 2026-04-03 12:00 |
23:14:57.35 |
+21:11:19.2 |
HIP 114759 |
18.33 |
| 2026-04-04 00:00 |
23:15:40.95 |
+21:17:28.1 |
HIP 114881 |
15.92 |
| 2026-04-04 12:00 |
23:16:24.47 |
+21:23:37.0 |
HIP 114953 |
8.18 |
| 2026-04-05 00:00 |
23:17:07.90 |
+21:29:45.9 |
HIP 114955 |
5.38 |
| 2026-04-05 12:00 |
23:17:51.24 |
+21:35:54.6 |
HIP 114955 |
16.28 |
| 2026-04-06 00:00 |
23:18:34.50 |
+21:42:03.4 |
HIP 114955 |
27.91 |
| 2026-04-06 12:00 |
23:19:17.67 |
+21:48:12.1 |
HIP 115268 |
23.22 |
| 2026-04-07 00:00 |
23:20:00.75 |
+21:54:20.7 |
HIP 115268 |
11.67 |
| 2026-04-07 12:00 |
23:20:43.74 |
+22:00:29.3 |
HIP 115268 |
2.97 |
| 2026-04-08 00:00 |
23:21:26.64 |
+22:06:37.8 |
HIP 115268 |
12.46 |
| 2026-04-08 12:00 |
23:22:09.46 |
+22:12:46.2 |
HIP 115419 |
10.26 |
| 2026-04-09 00:00 |
23:22:52.18 |
+22:18:54.6 |
HIP 115419 |
10.94 |
| 2026-04-09 12:00 |
23:23:34.82 |
+22:25:02.9 |
HIP 115558 |
16.18 |
| 2026-04-10 00:00 |
23:24:17.37 |
+22:31:11.2 |
HIP 115558 |
16.98 |
| 2026-04-10 12:00 |
23:24:59.83 |
+22:37:19.4 |
HIP 115558 |
24.16 |
| 2026-04-11 00:00 |
23:25:42.20 |
+22:43:27.5 |
HIP 115606 |
21.74 |
| 2026-04-11 12:00 |
23:26:24.47 |
+22:49:35.5 |
HIP 115606 |
22.76 |
| 2026-04-12 00:00 |
23:27:06.66 |
+22:55:43.4 |
HIP 115915 |
28.32 |
| 2026-04-12 12:00 |
23:27:48.76 |
+23:01:51.3 |
HIP 115915 |
17.73 |
| 2026-04-13 00:00 |
23:28:30.76 |
+23:07:59.1 |
HIP 115915 |
9.51 |
| 2026-04-13 12:00 |
23:29:12.68 |
+23:14:06.8 |
HIP 115962 |
7.94 |
| 2026-04-14 00:00 |
23:29:54.50 |
+23:20:14.4 |
HIP 115962 |
11.87 |
| 2026-04-14 12:00 |
23:30:36.22 |
+23:26:21.8 |
HIP 115962 |
21.85 |
| 2026-04-15 00:00 |
23:31:17.86 |
+23:32:29.2 |
HIP 116187 |
24.38 |
| 2026-04-15 12:00 |
23:31:59.40 |
+23:38:36.5 |
HIP 116187 |
13.79 |
| 2026-04-16 00:00 |
23:32:40.85 |
+23:44:43.7 |
HIP 116187 |
6.48 |