| Parameter |
Value |
| Designation |
C/2013 O3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-09-09T23:40:11.818560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:38Z |
| Obs used |
103 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-10-05.0000000 |
| e |
0.99612066 |
| q (au) |
3.180104 |
| a (au) |
819.754366 |
| i (deg) |
102.839741 |
| Ω (om, deg) |
276.752114 |
| ω (w, deg) |
337.968517 |
| M (ma, deg) |
0.001050 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.626 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.626 |
| n |
2.000 |
| gf |
0.992 |
| gb |
-1.000 |
| k |
0.995 |
| 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) |
| 2026-07-29 00:00 |
10:33:47.26 |
+73:24:39.7 |
HIP 51521 |
11.44 |
| 2026-07-29 12:00 |
10:33:57.57 |
+73:24:01.4 |
HIP 51521 |
11.88 |
| 2026-07-30 00:00 |
10:34:07.92 |
+73:23:23.4 |
HIP 51521 |
12.38 |
| 2026-07-30 12:00 |
10:34:18.31 |
+73:22:45.7 |
HIP 51521 |
12.94 |
| 2026-07-31 00:00 |
10:34:28.74 |
+73:22:08.4 |
HIP 51521 |
13.56 |
| 2026-07-31 12:00 |
10:34:39.22 |
+73:21:31.5 |
HIP 51521 |
14.22 |
| 2026-08-01 00:00 |
10:34:49.74 |
+73:20:54.8 |
HIP 51521 |
14.91 |
| 2026-08-01 12:00 |
10:35:00.29 |
+73:20:18.5 |
HIP 51521 |
15.64 |
| 2026-08-02 00:00 |
10:35:10.89 |
+73:19:42.6 |
HIP 51521 |
16.40 |
| 2026-08-02 12:00 |
10:35:21.53 |
+73:19:07.0 |
HIP 51521 |
17.18 |
| 2026-08-03 00:00 |
10:35:32.20 |
+73:18:31.7 |
HIP 51521 |
17.99 |
| 2026-08-03 12:00 |
10:35:42.91 |
+73:17:56.8 |
HIP 51521 |
18.81 |
| 2026-08-04 00:00 |
10:35:53.66 |
+73:17:22.3 |
HIP 51521 |
19.65 |
| 2026-08-04 12:00 |
10:36:04.45 |
+73:16:48.0 |
HIP 51521 |
20.50 |
| 2026-08-05 00:00 |
10:36:15.27 |
+73:16:14.2 |
HIP 51521 |
21.36 |
| 2026-08-05 12:00 |
10:36:26.13 |
+73:15:40.7 |
HIP 51521 |
22.23 |
| 2026-08-06 00:00 |
10:36:37.02 |
+73:15:07.5 |
HIP 51521 |
23.12 |
| 2026-08-06 12:00 |
10:36:47.95 |
+73:14:34.7 |
HIP 51521 |
24.01 |
| 2026-08-07 00:00 |
10:36:58.91 |
+73:14:02.3 |
HIP 51521 |
24.90 |
| 2026-08-07 12:00 |
10:37:09.90 |
+73:13:30.3 |
HIP 51521 |
25.80 |
| 2026-08-08 00:00 |
10:37:20.93 |
+73:12:58.6 |
HIP 51521 |
26.71 |
| 2026-08-08 12:00 |
10:37:31.98 |
+73:12:27.2 |
HIP 52030 |
27.05 |
| 2026-08-09 00:00 |
10:37:43.07 |
+73:11:56.3 |
HIP 52030 |
26.50 |
| 2026-08-09 12:00 |
10:37:54.19 |
+73:11:25.7 |
HIP 52030 |
25.99 |
| 2026-08-10 00:00 |
10:38:05.34 |
+73:10:55.4 |
HIP 52030 |
25.51 |
| 2026-08-10 12:00 |
10:38:16.51 |
+73:10:25.6 |
HIP 52030 |
25.06 |
| 2026-08-11 00:00 |
10:38:27.72 |
+73:09:56.1 |
HIP 52030 |
24.65 |
| 2026-08-11 12:00 |
10:38:38.95 |
+73:09:27.1 |
HIP 52030 |
24.28 |
| 2026-08-12 00:00 |
10:38:50.21 |
+73:08:58.3 |
HIP 52030 |
23.94 |
| 2026-08-12 12:00 |
10:39:01.49 |
+73:08:30.0 |
HIP 52030 |
23.65 |
| 2026-08-13 00:00 |
10:39:12.80 |
+73:08:02.1 |
HIP 52030 |
23.40 |
| 2026-08-13 12:00 |
10:39:24.14 |
+73:07:34.5 |
HIP 52030 |
23.19 |
| 2026-08-14 00:00 |
10:39:35.49 |
+73:07:07.4 |
HIP 52030 |
23.02 |
| 2026-08-14 12:00 |
10:39:46.87 |
+73:06:40.6 |
HIP 52030 |
22.90 |
| 2026-08-15 00:00 |
10:39:58.28 |
+73:06:14.2 |
HIP 52030 |
22.83 |
| 2026-08-15 12:00 |
10:40:09.70 |
+73:05:48.2 |
HIP 52030 |
22.80 |
| 2026-08-16 00:00 |
10:40:21.15 |
+73:05:22.6 |
HIP 52030 |
22.82 |
| 2026-08-16 12:00 |
10:40:32.61 |
+73:04:57.4 |
HIP 52030 |
22.88 |
| 2026-08-17 00:00 |
10:40:44.10 |
+73:04:32.6 |
HIP 52030 |
22.99 |
| 2026-08-17 12:00 |
10:40:55.60 |
+73:04:08.2 |
HIP 52030 |
23.14 |
| 2026-08-18 00:00 |
10:41:07.13 |
+73:03:44.2 |
HIP 52030 |
23.33 |
| 2026-08-18 12:00 |
10:41:18.67 |
+73:03:20.6 |
HIP 52030 |
23.57 |
| 2026-08-19 00:00 |
10:41:30.22 |
+73:02:57.4 |
HIP 52030 |
23.85 |