| 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 |
0.999 |
| 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) |
| 2026-07-29 00:00 |
09:53:01.21 |
+46:38:30.7 |
HIP 48506 |
6.93 |
| 2026-07-29 12:00 |
09:53:06.94 |
+46:38:05.5 |
HIP 48506 |
5.93 |
| 2026-07-30 00:00 |
09:53:12.68 |
+46:37:40.5 |
HIP 48506 |
4.95 |
| 2026-07-30 12:00 |
09:53:18.44 |
+46:37:15.8 |
HIP 48506 |
4.02 |
| 2026-07-31 00:00 |
09:53:24.21 |
+46:36:51.2 |
HIP 48506 |
3.18 |
| 2026-07-31 12:00 |
09:53:29.99 |
+46:36:26.9 |
HIP 48506 |
2.53 |
| 2026-08-01 00:00 |
09:53:35.79 |
+46:36:02.8 |
HIP 48506 |
2.23 |
| 2026-08-01 12:00 |
09:53:41.59 |
+46:35:39.0 |
HIP 48506 |
2.43 |
| 2026-08-02 00:00 |
09:53:47.42 |
+46:35:15.3 |
HIP 48506 |
3.03 |
| 2026-08-02 12:00 |
09:53:53.25 |
+46:34:51.9 |
HIP 48506 |
3.84 |
| 2026-08-03 00:00 |
09:53:59.09 |
+46:34:28.7 |
HIP 48506 |
4.77 |
| 2026-08-03 12:00 |
09:54:04.95 |
+46:34:05.7 |
HIP 48506 |
5.74 |
| 2026-08-04 00:00 |
09:54:10.82 |
+46:33:43.0 |
HIP 48506 |
6.75 |
| 2026-08-04 12:00 |
09:54:16.69 |
+46:33:20.5 |
HIP 48506 |
7.78 |
| 2026-08-05 00:00 |
09:54:22.58 |
+46:32:58.2 |
HIP 48506 |
8.83 |
| 2026-08-05 12:00 |
09:54:28.48 |
+46:32:36.2 |
HIP 48506 |
9.88 |
| 2026-08-06 00:00 |
09:54:34.39 |
+46:32:14.3 |
HIP 48506 |
10.94 |
| 2026-08-06 12:00 |
09:54:40.31 |
+46:31:52.8 |
HIP 48506 |
12.00 |
| 2026-08-07 00:00 |
09:54:46.23 |
+46:31:31.4 |
HIP 48506 |
13.07 |
| 2026-08-07 12:00 |
09:54:52.17 |
+46:31:10.3 |
HIP 48506 |
14.14 |
| 2026-08-08 00:00 |
09:54:58.11 |
+46:30:49.5 |
HIP 48506 |
15.21 |
| 2026-08-08 12:00 |
09:55:04.06 |
+46:30:28.9 |
HIP 48506 |
16.28 |
| 2026-08-09 00:00 |
09:55:10.02 |
+46:30:08.5 |
HIP 48506 |
17.36 |
| 2026-08-09 12:00 |
09:55:15.99 |
+46:29:48.4 |
HIP 48506 |
18.43 |
| 2026-08-10 00:00 |
09:55:21.96 |
+46:29:28.6 |
HIP 48506 |
19.51 |
| 2026-08-10 12:00 |
09:55:27.95 |
+46:29:08.9 |
HIP 48506 |
20.59 |
| 2026-08-11 00:00 |
09:55:33.93 |
+46:28:49.6 |
HIP 48506 |
21.66 |
| 2026-08-11 12:00 |
09:55:39.93 |
+46:28:30.5 |
HIP 48506 |
22.74 |
| 2026-08-12 00:00 |
09:55:45.92 |
+46:28:11.6 |
HIP 48506 |
23.82 |
| 2026-08-12 12:00 |
09:55:51.93 |
+46:27:53.0 |
HIP 48506 |
24.90 |
| 2026-08-13 00:00 |
09:55:57.94 |
+46:27:34.7 |
HIP 48506 |
25.98 |
| 2026-08-13 12:00 |
09:56:03.95 |
+46:27:16.6 |
HIP 48506 |
27.05 |
| 2026-08-14 00:00 |
09:56:09.97 |
+46:26:58.8 |
HIP 48914 |
26.22 |
| 2026-08-14 12:00 |
09:56:15.99 |
+46:26:41.3 |
HIP 48914 |
25.20 |
| 2026-08-15 00:00 |
09:56:22.01 |
+46:26:24.0 |
HIP 48914 |
24.19 |
| 2026-08-15 12:00 |
09:56:28.04 |
+46:26:07.0 |
HIP 48914 |
23.17 |
| 2026-08-16 00:00 |
09:56:34.07 |
+46:25:50.3 |
HIP 48914 |
22.17 |
| 2026-08-16 12:00 |
09:56:40.10 |
+46:25:33.8 |
HIP 48914 |
21.17 |
| 2026-08-17 00:00 |
09:56:46.13 |
+46:25:17.6 |
HIP 48914 |
20.17 |
| 2026-08-17 12:00 |
09:56:52.16 |
+46:25:01.7 |
HIP 48914 |
19.18 |
| 2026-08-18 00:00 |
09:56:58.20 |
+46:24:46.1 |
HIP 48914 |
18.21 |
| 2026-08-18 12:00 |
09:57:04.24 |
+46:24:30.7 |
HIP 48914 |
17.24 |
| 2026-08-19 00:00 |
09:57:10.27 |
+46:24:15.6 |
HIP 48914 |
16.28 |