| 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) |
| 2026-09-20 00:00 |
01:46:48.26 |
+67:30:59.4 |
HIP 8506 |
18.64 |
| 2026-09-20 12:00 |
01:46:39.82 |
+67:31:18.8 |
HIP 8506 |
19.21 |
| 2026-09-21 00:00 |
01:46:31.33 |
+67:31:37.9 |
HIP 8506 |
19.82 |
| 2026-09-21 12:00 |
01:46:22.79 |
+67:31:56.5 |
HIP 8506 |
20.45 |
| 2026-09-22 00:00 |
01:46:14.21 |
+67:32:14.6 |
HIP 8506 |
21.10 |
| 2026-09-22 12:00 |
01:46:05.58 |
+67:32:32.4 |
HIP 8506 |
21.77 |
| 2026-09-23 00:00 |
01:45:56.91 |
+67:32:49.7 |
HIP 8506 |
22.46 |
| 2026-09-23 12:00 |
01:45:48.20 |
+67:33:06.7 |
HIP 8506 |
23.17 |
| 2026-09-24 00:00 |
01:45:39.45 |
+67:33:23.2 |
HIP 8506 |
23.90 |
| 2026-09-24 12:00 |
01:45:30.66 |
+67:33:39.2 |
HIP 8506 |
24.64 |
| 2026-09-25 00:00 |
01:45:21.83 |
+67:33:54.9 |
HIP 8506 |
25.40 |
| 2026-09-25 12:00 |
01:45:12.95 |
+67:34:10.1 |
HIP 8506 |
26.17 |
| 2026-09-26 00:00 |
01:45:04.04 |
+67:34:24.9 |
HIP 8506 |
26.95 |
| 2026-09-26 12:00 |
01:44:55.09 |
+67:34:39.2 |
HIP 8506 |
27.74 |
| 2026-09-27 00:00 |
01:44:46.10 |
+67:34:53.2 |
HIP 8506 |
28.54 |
| 2026-09-27 12:00 |
01:44:37.08 |
+67:35:06.7 |
HIP 8506 |
29.35 |
| 2026-09-28 00:00 |
01:44:28.02 |
+67:35:19.7 |
HIP 7965 |
29.80 |
| 2026-09-28 12:00 |
01:44:18.92 |
+67:35:32.4 |
HIP 7965 |
29.26 |
| 2026-09-29 00:00 |
01:44:09.79 |
+67:35:44.6 |
HIP 7965 |
28.76 |
| 2026-09-29 12:00 |
01:44:00.63 |
+67:35:56.3 |
HIP 7965 |
28.27 |
| 2026-09-30 00:00 |
01:43:51.43 |
+67:36:07.6 |
HIP 7965 |
27.81 |
| 2026-09-30 12:00 |
01:43:42.20 |
+67:36:18.5 |
HIP 7965 |
27.38 |
| 2026-10-01 00:00 |
01:43:32.94 |
+67:36:29.0 |
HIP 7965 |
26.98 |
| 2026-10-01 12:00 |
01:43:23.64 |
+67:36:39.0 |
HIP 7965 |
26.61 |
| 2026-10-02 00:00 |
01:43:14.32 |
+67:36:48.5 |
HIP 7965 |
26.27 |
| 2026-10-02 12:00 |
01:43:04.96 |
+67:36:57.6 |
HIP 7965 |
25.96 |
| 2026-10-03 00:00 |
01:42:55.58 |
+67:37:06.3 |
HIP 7965 |
25.69 |
| 2026-10-03 12:00 |
01:42:46.17 |
+67:37:14.5 |
HIP 7965 |
25.46 |
| 2026-10-04 00:00 |
01:42:36.73 |
+67:37:22.3 |
HIP 7965 |
25.26 |
| 2026-10-04 12:00 |
01:42:27.26 |
+67:37:29.6 |
HIP 7965 |
25.10 |
| 2026-10-05 00:00 |
01:42:17.77 |
+67:37:36.4 |
HIP 7965 |
24.98 |
| 2026-10-05 12:00 |
01:42:08.26 |
+67:37:42.9 |
HIP 7965 |
24.90 |
| 2026-10-06 00:00 |
01:41:58.72 |
+67:37:48.8 |
HIP 7590 |
24.34 |
| 2026-10-06 12:00 |
01:41:49.15 |
+67:37:54.3 |
HIP 7590 |
23.44 |
| 2026-10-07 00:00 |
01:41:39.56 |
+67:37:59.4 |
HIP 7590 |
22.54 |
| 2026-10-07 12:00 |
01:41:29.96 |
+67:38:04.0 |
HIP 7590 |
21.64 |
| 2026-10-08 00:00 |
01:41:20.33 |
+67:38:08.1 |
HIP 7590 |
20.74 |
| 2026-10-08 12:00 |
01:41:10.68 |
+67:38:11.8 |
HIP 7590 |
19.84 |
| 2026-10-09 00:00 |
01:41:01.01 |
+67:38:15.1 |
HIP 7590 |
18.93 |
| 2026-10-09 12:00 |
01:40:51.32 |
+67:38:17.8 |
HIP 7590 |
18.03 |
| 2026-10-10 00:00 |
01:40:41.62 |
+67:38:20.2 |
HIP 7590 |
17.12 |
| 2026-10-10 12:00 |
01:40:31.90 |
+67:38:22.0 |
HIP 7590 |
16.22 |
| 2026-10-11 00:00 |
01:40:22.16 |
+67:38:23.4 |
HIP 7590 |
15.31 |