| Parameter |
Value |
| Designation |
C/2009 T1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2009-10-08T06:04:38.959680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:34Z |
| Obs used |
141 |
| NEO |
- |
| M1 |
8.100 |
| K1 |
7.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-04-02.0000000 |
| e |
0.99830743 |
| q (au) |
6.220409 |
| a (au) |
3675.119595 |
| i (deg) |
89.893932 |
| Ω (om, deg) |
54.407386 |
| ω (w, deg) |
282.529051 |
| M (ma, deg) |
0.000777 |
Magnitude
Scatter + Global Linear
$$
M_a = (1.546 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
1.546 |
| n |
6.000 |
| gf |
0.998 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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 |
01:55:48.90 |
+66:25:47.0 |
HIP 8867 |
18.37 |
| 2026-07-29 12:00 |
01:55:47.56 |
+66:26:35.7 |
HIP 8867 |
18.97 |
| 2026-07-30 00:00 |
01:55:46.14 |
+66:27:24.3 |
HIP 8867 |
19.58 |
| 2026-07-30 12:00 |
01:55:44.65 |
+66:28:12.7 |
HIP 9264 |
19.96 |
| 2026-07-31 00:00 |
01:55:43.09 |
+66:29:01.0 |
HIP 9264 |
20.07 |
| 2026-07-31 12:00 |
01:55:41.45 |
+66:29:49.2 |
HIP 9264 |
20.22 |
| 2026-08-01 00:00 |
01:55:39.74 |
+66:30:37.3 |
HIP 9264 |
20.41 |
| 2026-08-01 12:00 |
01:55:37.95 |
+66:31:25.3 |
HIP 9264 |
20.64 |
| 2026-08-02 00:00 |
01:55:36.09 |
+66:32:13.1 |
HIP 9264 |
20.90 |
| 2026-08-02 12:00 |
01:55:34.16 |
+66:33:00.8 |
HIP 9264 |
21.20 |
| 2026-08-03 00:00 |
01:55:32.15 |
+66:33:48.3 |
HIP 8717 |
21.27 |
| 2026-08-03 12:00 |
01:55:30.07 |
+66:34:35.7 |
HIP 8717 |
21.34 |
| 2026-08-04 00:00 |
01:55:27.91 |
+66:35:22.9 |
HIP 8717 |
21.43 |
| 2026-08-04 12:00 |
01:55:25.68 |
+66:36:10.0 |
HIP 8717 |
21.54 |
| 2026-08-05 00:00 |
01:55:23.37 |
+66:36:57.0 |
HIP 8717 |
21.68 |
| 2026-08-05 12:00 |
01:55:20.99 |
+66:37:43.7 |
HIP 8717 |
21.84 |
| 2026-08-06 00:00 |
01:55:18.53 |
+66:38:30.4 |
HIP 8717 |
22.02 |
| 2026-08-06 12:00 |
01:55:16.00 |
+66:39:16.8 |
HIP 8717 |
22.23 |
| 2026-08-07 00:00 |
01:55:13.40 |
+66:40:03.1 |
HIP 8717 |
22.45 |
| 2026-08-07 12:00 |
01:55:10.71 |
+66:40:49.3 |
HIP 8717 |
22.69 |
| 2026-08-08 00:00 |
01:55:07.96 |
+66:41:35.2 |
HIP 8717 |
22.95 |
| 2026-08-08 12:00 |
01:55:05.13 |
+66:42:21.0 |
HIP 8717 |
23.23 |
| 2026-08-09 00:00 |
01:55:02.22 |
+66:43:06.6 |
HIP 8717 |
23.53 |
| 2026-08-09 12:00 |
01:54:59.24 |
+66:43:52.0 |
HIP 8717 |
23.84 |
| 2026-08-10 00:00 |
01:54:56.18 |
+66:44:37.2 |
HIP 8717 |
24.17 |
| 2026-08-10 12:00 |
01:54:53.05 |
+66:45:22.3 |
HIP 8717 |
24.52 |
| 2026-08-11 00:00 |
01:54:49.84 |
+66:46:07.1 |
HIP 8717 |
24.88 |
| 2026-08-11 12:00 |
01:54:46.56 |
+66:46:51.8 |
HIP 8717 |
25.25 |
| 2026-08-12 00:00 |
01:54:43.21 |
+66:47:36.2 |
HIP 8717 |
25.64 |
| 2026-08-12 12:00 |
01:54:39.77 |
+66:48:20.5 |
HIP 8717 |
26.04 |
| 2026-08-13 00:00 |
01:54:36.27 |
+66:49:04.5 |
HIP 8717 |
26.45 |
| 2026-08-13 12:00 |
01:54:32.68 |
+66:49:48.3 |
HIP 8717 |
26.87 |
| 2026-08-14 00:00 |
01:54:29.03 |
+66:50:32.0 |
HIP 8717 |
27.31 |
| 2026-08-14 12:00 |
01:54:25.30 |
+66:51:15.4 |
HIP 8717 |
27.75 |
| 2026-08-15 00:00 |
01:54:21.49 |
+66:51:58.5 |
HIP 8717 |
28.21 |
| 2026-08-15 12:00 |
01:54:17.61 |
+66:52:41.5 |
HIP 8717 |
28.67 |
| 2026-08-16 00:00 |
01:54:13.66 |
+66:53:24.2 |
HIP 8717 |
29.15 |
| 2026-08-16 12:00 |
01:54:09.63 |
+66:54:06.7 |
HIP 8717 |
29.63 |
| 2026-08-17 00:00 |
01:54:05.53 |
+66:54:49.0 |
HIP 8717 |
30.12 |
| 2026-08-17 12:00 |
01:54:01.36 |
+66:55:31.0 |
HIP 8458 |
30.34 |
| 2026-08-18 00:00 |
01:53:57.11 |
+66:56:12.8 |
HIP 8458 |
30.13 |
| 2026-08-18 12:00 |
01:53:52.79 |
+66:56:54.3 |
HIP 8458 |
29.94 |
| 2026-08-19 00:00 |
01:53:48.39 |
+66:57:35.6 |
HIP 8458 |
29.76 |