C/2012 Y3 (McNaught)
| Parameter |
Value |
| Designation |
C/2012 Y3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-08-25T20:18:44.000640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:30Z |
| Obs used |
150 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-02-01.0000000 |
| e |
0.93994217 |
| q (au) |
1.764843 |
| a (au) |
29.385733 |
| i (deg) |
73.231907 |
| Ω (om, deg) |
122.707962 |
| ω (w, deg) |
235.694296 |
| M (ma, deg) |
0.984727 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.507 + 5.732\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.507 |
| n |
5.732 |
| gf |
0.994 |
| 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) |
| 2026-02-03 00:00 |
09:58:09.92 |
+48:18:47.9 |
HIP 48871 |
5.75 |
| 2026-02-03 12:00 |
09:58:03.79 |
+48:19:20.1 |
HIP 48871 |
6.15 |
| 2026-02-04 00:00 |
09:57:57.64 |
+48:19:52.0 |
HIP 48871 |
6.71 |
| 2026-02-04 12:00 |
09:57:51.48 |
+48:20:23.5 |
HIP 48871 |
7.41 |
| 2026-02-05 00:00 |
09:57:45.30 |
+48:20:54.7 |
HIP 48871 |
8.21 |
| 2026-02-05 12:00 |
09:57:39.11 |
+48:21:25.6 |
HIP 48871 |
9.08 |
| 2026-02-06 00:00 |
09:57:32.91 |
+48:21:56.1 |
HIP 48871 |
10.00 |
| 2026-02-06 12:00 |
09:57:26.70 |
+48:22:26.2 |
HIP 48871 |
10.96 |
| 2026-02-07 00:00 |
09:57:20.48 |
+48:22:56.0 |
HIP 48871 |
11.95 |
| 2026-02-07 12:00 |
09:57:14.24 |
+48:23:25.5 |
HIP 48871 |
12.97 |
| 2026-02-08 00:00 |
09:57:08.00 |
+48:23:54.6 |
HIP 48871 |
14.00 |
| 2026-02-08 12:00 |
09:57:01.75 |
+48:24:23.3 |
HIP 48673 |
14.80 |
| 2026-02-09 00:00 |
09:56:55.48 |
+48:24:51.7 |
HIP 48673 |
13.67 |
| 2026-02-09 12:00 |
09:56:49.21 |
+48:25:19.7 |
HIP 48673 |
12.55 |
| 2026-02-10 00:00 |
09:56:42.93 |
+48:25:47.3 |
HIP 48673 |
11.43 |
| 2026-02-10 12:00 |
09:56:36.65 |
+48:26:14.6 |
HIP 48673 |
10.32 |
| 2026-02-11 00:00 |
09:56:30.36 |
+48:26:41.5 |
HIP 48673 |
9.21 |
| 2026-02-11 12:00 |
09:56:24.06 |
+48:27:08.1 |
HIP 48673 |
8.11 |
| 2026-02-12 00:00 |
09:56:17.76 |
+48:27:34.2 |
HIP 48673 |
7.02 |
| 2026-02-12 12:00 |
09:56:11.45 |
+48:28:00.0 |
HIP 48673 |
5.94 |
| 2026-02-13 00:00 |
09:56:05.14 |
+48:28:25.4 |
HIP 48673 |
4.89 |
| 2026-02-13 12:00 |
09:55:58.82 |
+48:28:50.5 |
HIP 48673 |
3.89 |
| 2026-02-14 00:00 |
09:55:52.51 |
+48:29:15.1 |
HIP 48673 |
2.97 |
| 2026-02-14 12:00 |
09:55:46.19 |
+48:29:39.4 |
HIP 48673 |
2.24 |
| 2026-02-15 00:00 |
09:55:39.86 |
+48:30:03.3 |
HIP 48673 |
1.93 |
| 2026-02-15 12:00 |
09:55:33.54 |
+48:30:26.8 |
HIP 48673 |
2.21 |
| 2026-02-16 00:00 |
09:55:27.22 |
+48:30:49.9 |
HIP 48673 |
2.92 |
| 2026-02-16 12:00 |
09:55:20.90 |
+48:31:12.7 |
HIP 48673 |
3.83 |
| 2026-02-17 00:00 |
09:55:14.58 |
+48:31:35.0 |
HIP 48673 |
4.82 |
| 2026-02-17 12:00 |
09:55:08.26 |
+48:31:56.9 |
HIP 48673 |
5.84 |
| 2026-02-18 00:00 |
09:55:01.94 |
+48:32:18.5 |
HIP 48673 |
6.89 |
| 2026-02-18 12:00 |
09:54:55.62 |
+48:32:39.6 |
HIP 48673 |
7.95 |
| 2026-02-19 00:00 |
09:54:49.31 |
+48:33:00.4 |
HIP 48673 |
9.02 |
| 2026-02-19 12:00 |
09:54:43.00 |
+48:33:20.8 |
HIP 48673 |
10.09 |
| 2026-02-20 00:00 |
09:54:36.70 |
+48:33:40.7 |
HIP 48673 |
11.16 |
| 2026-02-20 12:00 |
09:54:30.40 |
+48:34:00.3 |
HIP 48673 |
12.23 |
| 2026-02-21 00:00 |
09:54:24.11 |
+48:34:19.5 |
HIP 48673 |
13.30 |
| 2026-02-21 12:00 |
09:54:17.83 |
+48:34:38.2 |
HIP 48673 |
14.37 |
| 2026-02-22 00:00 |
09:54:11.55 |
+48:34:56.6 |
HIP 48673 |
15.44 |
| 2026-02-22 12:00 |
09:54:05.28 |
+48:35:14.5 |
HIP 48673 |
16.51 |
| 2026-02-23 00:00 |
09:53:59.02 |
+48:35:32.1 |
HIP 48673 |
17.57 |
| 2026-02-23 12:00 |
09:53:52.76 |
+48:35:49.2 |
HIP 48673 |
18.63 |
| 2026-02-24 00:00 |
09:53:46.52 |
+48:36:06.0 |
HIP 48673 |
19.69 |