| 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) |
| 2026-07-29 00:00 |
07:30:38.76 |
+26:20:05.5 |
HIP 36601 |
15.46 |
| 2026-07-29 12:00 |
07:30:43.03 |
+26:19:59.4 |
HIP 36601 |
14.69 |
| 2026-07-30 00:00 |
07:30:47.28 |
+26:19:53.3 |
HIP 36601 |
13.95 |
| 2026-07-30 12:00 |
07:30:51.53 |
+26:19:47.3 |
HIP 36601 |
13.23 |
| 2026-07-31 00:00 |
07:30:55.76 |
+26:19:41.3 |
HIP 36601 |
12.55 |
| 2026-07-31 12:00 |
07:30:59.98 |
+26:19:35.4 |
HIP 36601 |
11.91 |
| 2026-08-01 00:00 |
07:31:04.20 |
+26:19:29.5 |
HIP 36601 |
11.31 |
| 2026-08-01 12:00 |
07:31:08.40 |
+26:19:23.6 |
HIP 36601 |
10.76 |
| 2026-08-02 00:00 |
07:31:12.60 |
+26:19:17.9 |
HIP 36601 |
10.27 |
| 2026-08-02 12:00 |
07:31:16.78 |
+26:19:12.1 |
HIP 36601 |
9.85 |
| 2026-08-03 00:00 |
07:31:20.95 |
+26:19:06.4 |
HIP 36601 |
9.50 |
| 2026-08-03 12:00 |
07:31:25.11 |
+26:19:00.8 |
HIP 36601 |
9.23 |
| 2026-08-04 00:00 |
07:31:29.26 |
+26:18:55.2 |
HIP 36601 |
9.06 |
| 2026-08-04 12:00 |
07:31:33.40 |
+26:18:49.7 |
HIP 36601 |
8.98 |
| 2026-08-05 00:00 |
07:31:37.53 |
+26:18:44.2 |
HIP 36601 |
8.99 |
| 2026-08-05 12:00 |
07:31:41.64 |
+26:18:38.8 |
HIP 36601 |
9.10 |
| 2026-08-06 00:00 |
07:31:45.74 |
+26:18:33.4 |
HIP 36601 |
9.30 |
| 2026-08-06 12:00 |
07:31:49.83 |
+26:18:28.1 |
HIP 36601 |
9.58 |
| 2026-08-07 00:00 |
07:31:53.90 |
+26:18:22.8 |
HIP 36601 |
9.93 |
| 2026-08-07 12:00 |
07:31:57.97 |
+26:18:17.6 |
HIP 36601 |
10.36 |
| 2026-08-08 00:00 |
07:32:02.02 |
+26:18:12.5 |
HIP 36601 |
10.84 |
| 2026-08-08 12:00 |
07:32:06.05 |
+26:18:07.4 |
HIP 36601 |
11.37 |
| 2026-08-09 00:00 |
07:32:10.07 |
+26:18:02.3 |
HIP 36601 |
11.95 |
| 2026-08-09 12:00 |
07:32:14.08 |
+26:17:57.4 |
HIP 36601 |
12.56 |
| 2026-08-10 00:00 |
07:32:18.07 |
+26:17:52.4 |
HIP 36601 |
13.20 |
| 2026-08-10 12:00 |
07:32:22.04 |
+26:17:47.6 |
HIP 36601 |
13.87 |
| 2026-08-11 00:00 |
07:32:26.01 |
+26:17:42.8 |
HIP 36601 |
14.56 |
| 2026-08-11 12:00 |
07:32:29.95 |
+26:17:38.1 |
HIP 36725 |
14.45 |
| 2026-08-12 00:00 |
07:32:33.88 |
+26:17:33.4 |
HIP 36725 |
13.82 |
| 2026-08-12 12:00 |
07:32:37.80 |
+26:17:28.8 |
HIP 36725 |
13.22 |
| 2026-08-13 00:00 |
07:32:41.70 |
+26:17:24.2 |
HIP 36725 |
12.66 |
| 2026-08-13 12:00 |
07:32:45.58 |
+26:17:19.7 |
HIP 36725 |
12.14 |
| 2026-08-14 00:00 |
07:32:49.44 |
+26:17:15.3 |
HIP 36725 |
11.66 |
| 2026-08-14 12:00 |
07:32:53.29 |
+26:17:10.9 |
HIP 36725 |
11.23 |
| 2026-08-15 00:00 |
07:32:57.12 |
+26:17:06.6 |
HIP 36725 |
10.86 |
| 2026-08-15 12:00 |
07:33:00.94 |
+26:17:02.4 |
HIP 36725 |
10.55 |
| 2026-08-16 00:00 |
07:33:04.73 |
+26:16:58.2 |
HIP 36725 |
10.30 |
| 2026-08-16 12:00 |
07:33:08.51 |
+26:16:54.1 |
HIP 36725 |
10.12 |
| 2026-08-17 00:00 |
07:33:12.27 |
+26:16:50.1 |
HIP 36725 |
10.01 |
| 2026-08-17 12:00 |
07:33:16.01 |
+26:16:46.1 |
HIP 36725 |
9.97 |
| 2026-08-18 00:00 |
07:33:19.73 |
+26:16:42.2 |
HIP 36725 |
10.00 |
| 2026-08-18 12:00 |
07:33:23.43 |
+26:16:38.3 |
HIP 36725 |
10.10 |
| 2026-08-19 00:00 |
07:33:27.12 |
+26:16:34.6 |
HIP 36725 |
10.27 |