| Parameter |
Value |
| Designation |
C/2012 T4 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-10-10T22:22:44.699520Z |
| Orbit solution date (soln_date, UTC) |
2022-06-07T21:44:03Z |
| Obs used |
49 |
| NEO |
- |
| M1 |
15.500 |
| K1 |
6.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-10-18.0000000 |
| e |
0.99118923 |
| q (au) |
1.955997 |
| a (au) |
222.000586 |
| i (deg) |
24.085273 |
| Ω (om, deg) |
99.368559 |
| ω (w, deg) |
219.915260 |
| M (ma, deg) |
0.002106 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.048 + 4.167\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.048 |
| n |
4.167 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.990 |
| 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) |
| 2026-09-20 00:00 |
07:36:33.50 |
+26:15:11.2 |
HIP 36912 |
26.48 |
| 2026-09-20 12:00 |
07:36:35.50 |
+26:15:12.7 |
HIP 36912 |
26.74 |
| 2026-09-21 00:00 |
07:36:37.46 |
+26:15:14.1 |
HIP 36912 |
27.00 |
| 2026-09-21 12:00 |
07:36:39.39 |
+26:15:15.7 |
HIP 36912 |
27.25 |
| 2026-09-22 00:00 |
07:36:41.29 |
+26:15:17.4 |
HIP 36912 |
27.51 |
| 2026-09-22 12:00 |
07:36:43.16 |
+26:15:19.2 |
HIP 36912 |
27.76 |
| 2026-09-23 00:00 |
07:36:45.00 |
+26:15:21.0 |
HIP 36912 |
28.01 |
| 2026-09-23 12:00 |
07:36:46.80 |
+26:15:23.0 |
HIP 36912 |
28.26 |
| 2026-09-24 00:00 |
07:36:48.57 |
+26:15:25.0 |
HIP 36912 |
28.50 |
| 2026-09-24 12:00 |
07:36:50.30 |
+26:15:27.1 |
HIP 36912 |
28.74 |
| 2026-09-25 00:00 |
07:36:52.01 |
+26:15:29.3 |
HIP 36912 |
28.98 |
| 2026-09-25 12:00 |
07:36:53.68 |
+26:15:31.6 |
HIP 36912 |
29.22 |
| 2026-09-26 00:00 |
07:36:55.31 |
+26:15:34.0 |
HIP 36912 |
29.45 |
| 2026-09-26 12:00 |
07:36:56.92 |
+26:15:36.4 |
HIP 36912 |
29.68 |
| 2026-09-27 00:00 |
07:36:58.49 |
+26:15:39.0 |
HIP 36912 |
29.91 |
| 2026-09-27 12:00 |
07:37:00.02 |
+26:15:41.7 |
HIP 36912 |
30.13 |
| 2026-09-28 00:00 |
07:37:01.53 |
+26:15:44.4 |
HIP 36912 |
30.35 |
| 2026-09-28 12:00 |
07:37:02.99 |
+26:15:47.2 |
HIP 36912 |
30.56 |
| 2026-09-29 00:00 |
07:37:04.43 |
+26:15:50.1 |
HIP 36912 |
30.77 |
| 2026-09-29 12:00 |
07:37:05.83 |
+26:15:53.1 |
HIP 36912 |
30.97 |
| 2026-09-30 00:00 |
07:37:07.19 |
+26:15:56.2 |
HIP 36912 |
31.17 |
| 2026-09-30 12:00 |
07:37:08.53 |
+26:15:59.4 |
HIP 36912 |
31.36 |
| 2026-10-01 00:00 |
07:37:09.82 |
+26:16:02.7 |
HIP 36912 |
31.55 |
| 2026-10-01 12:00 |
07:37:11.09 |
+26:16:06.1 |
HIP 36912 |
31.74 |
| 2026-10-02 00:00 |
07:37:12.31 |
+26:16:09.5 |
HIP 36912 |
31.91 |
| 2026-10-02 12:00 |
07:37:13.51 |
+26:16:13.1 |
HIP 36912 |
32.08 |
| 2026-10-03 00:00 |
07:37:14.67 |
+26:16:16.7 |
HIP 36912 |
32.25 |
| 2026-10-03 12:00 |
07:37:15.79 |
+26:16:20.4 |
HIP 37064 |
32.40 |
| 2026-10-04 00:00 |
07:37:16.88 |
+26:16:24.2 |
HIP 37064 |
32.49 |
| 2026-10-04 12:00 |
07:37:17.93 |
+26:16:28.1 |
HIP 37064 |
32.59 |
| 2026-10-05 00:00 |
07:37:18.94 |
+26:16:32.1 |
HIP 37064 |
32.68 |
| 2026-10-05 12:00 |
07:37:19.93 |
+26:16:36.2 |
HIP 37064 |
32.78 |
| 2026-10-06 00:00 |
07:37:20.87 |
+26:16:40.4 |
HIP 37064 |
32.88 |
| 2026-10-06 12:00 |
07:37:21.78 |
+26:16:44.6 |
HIP 37064 |
32.98 |
| 2026-10-07 00:00 |
07:37:22.65 |
+26:16:49.0 |
HIP 37064 |
33.08 |
| 2026-10-07 12:00 |
07:37:23.49 |
+26:16:53.4 |
HIP 37064 |
33.18 |
| 2026-10-08 00:00 |
07:37:24.29 |
+26:16:57.9 |
HIP 37064 |
33.29 |
| 2026-10-08 12:00 |
07:37:25.06 |
+26:17:02.6 |
HIP 37195 |
33.33 |
| 2026-10-09 00:00 |
07:37:25.78 |
+26:17:07.3 |
HIP 37195 |
33.19 |
| 2026-10-09 12:00 |
07:37:26.48 |
+26:17:12.1 |
HIP 37195 |
33.05 |
| 2026-10-10 00:00 |
07:37:27.13 |
+26:17:16.9 |
HIP 37195 |
32.92 |
| 2026-10-10 12:00 |
07:37:27.75 |
+26:17:21.9 |
HIP 37195 |
32.79 |
| 2026-10-11 00:00 |
07:37:28.33 |
+26:17:27.0 |
HIP 37195 |
32.66 |