C/2013 O3 (McNaught)
| 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 |
0.994 |
| 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) |
| 2026-02-03 00:00 |
11:13:56.53 |
+76:31:20.3 |
HIP 55312 |
29.43 |
| 2026-02-03 12:00 |
11:13:39.98 |
+76:32:01.1 |
HIP 55312 |
30.59 |
| 2026-02-04 00:00 |
11:13:23.31 |
+76:32:41.4 |
HIP 54560 |
30.82 |
| 2026-02-04 12:00 |
11:13:06.54 |
+76:33:21.1 |
HIP 54560 |
29.84 |
| 2026-02-05 00:00 |
11:12:49.66 |
+76:34:00.4 |
HIP 54560 |
28.89 |
| 2026-02-05 12:00 |
11:12:32.68 |
+76:34:39.2 |
HIP 54560 |
27.95 |
| 2026-02-06 00:00 |
11:12:15.60 |
+76:35:17.4 |
HIP 54560 |
27.04 |
| 2026-02-06 12:00 |
11:11:58.42 |
+76:35:55.1 |
HIP 54560 |
26.16 |
| 2026-02-07 00:00 |
11:11:41.14 |
+76:36:32.3 |
HIP 54560 |
25.30 |
| 2026-02-07 12:00 |
11:11:23.76 |
+76:37:08.9 |
HIP 54560 |
24.48 |
| 2026-02-08 00:00 |
11:11:06.28 |
+76:37:45.0 |
HIP 54560 |
23.70 |
| 2026-02-08 12:00 |
11:10:48.72 |
+76:38:20.6 |
HIP 54560 |
22.96 |
| 2026-02-09 00:00 |
11:10:31.06 |
+76:38:55.6 |
HIP 54560 |
22.26 |
| 2026-02-09 12:00 |
11:10:13.30 |
+76:39:30.1 |
HIP 54560 |
21.61 |
| 2026-02-10 00:00 |
11:09:55.46 |
+76:40:04.0 |
HIP 54560 |
21.02 |
| 2026-02-10 12:00 |
11:09:37.53 |
+76:40:37.4 |
HIP 54560 |
20.48 |
| 2026-02-11 00:00 |
11:09:19.52 |
+76:41:10.2 |
HIP 54560 |
20.01 |
| 2026-02-11 12:00 |
11:09:01.42 |
+76:41:42.4 |
HIP 54560 |
19.60 |
| 2026-02-12 00:00 |
11:08:43.24 |
+76:42:14.1 |
HIP 54560 |
19.27 |
| 2026-02-12 12:00 |
11:08:24.98 |
+76:42:45.2 |
HIP 54560 |
19.01 |
| 2026-02-13 00:00 |
11:08:06.64 |
+76:43:15.7 |
HIP 54560 |
18.83 |
| 2026-02-13 12:00 |
11:07:48.23 |
+76:43:45.6 |
HIP 54560 |
18.73 |
| 2026-02-14 00:00 |
11:07:29.73 |
+76:44:15.0 |
HIP 54560 |
18.71 |
| 2026-02-14 12:00 |
11:07:11.17 |
+76:44:43.8 |
HIP 54560 |
18.77 |
| 2026-02-15 00:00 |
11:06:52.54 |
+76:45:12.0 |
HIP 54560 |
18.91 |
| 2026-02-15 12:00 |
11:06:33.83 |
+76:45:39.6 |
HIP 54560 |
19.13 |
| 2026-02-16 00:00 |
11:06:15.06 |
+76:46:06.6 |
HIP 54560 |
19.43 |
| 2026-02-16 12:00 |
11:05:56.23 |
+76:46:33.0 |
HIP 54560 |
19.80 |
| 2026-02-17 00:00 |
11:05:37.33 |
+76:46:58.9 |
HIP 54560 |
20.24 |
| 2026-02-17 12:00 |
11:05:18.37 |
+76:47:24.1 |
HIP 53775 |
20.03 |
| 2026-02-18 00:00 |
11:04:59.36 |
+76:47:48.7 |
HIP 53775 |
19.28 |
| 2026-02-18 12:00 |
11:04:40.28 |
+76:48:12.7 |
HIP 53775 |
18.56 |
| 2026-02-19 00:00 |
11:04:21.15 |
+76:48:36.1 |
HIP 53775 |
17.88 |
| 2026-02-19 12:00 |
11:04:01.97 |
+76:48:58.8 |
HIP 53775 |
17.24 |
| 2026-02-20 00:00 |
11:03:42.74 |
+76:49:21.0 |
HIP 53775 |
16.66 |
| 2026-02-20 12:00 |
11:03:23.47 |
+76:49:42.6 |
HIP 53775 |
16.13 |
| 2026-02-21 00:00 |
11:03:04.14 |
+76:50:03.5 |
HIP 53775 |
15.66 |
| 2026-02-21 12:00 |
11:02:44.77 |
+76:50:23.8 |
HIP 53775 |
15.25 |
| 2026-02-22 00:00 |
11:02:25.36 |
+76:50:43.5 |
HIP 53775 |
14.91 |
| 2026-02-22 12:00 |
11:02:05.92 |
+76:51:02.5 |
HIP 53775 |
14.65 |
| 2026-02-23 00:00 |
11:01:46.43 |
+76:51:21.0 |
HIP 53775 |
14.47 |
| 2026-02-23 12:00 |
11:01:26.91 |
+76:51:38.8 |
HIP 53775 |
14.36 |
| 2026-02-24 00:00 |
11:01:07.36 |
+76:51:56.0 |
HIP 53775 |
14.34 |