| 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
$$
M_a = (1.547 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
1.547 |
| n |
6.000 |
| gf |
0.980 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.901 |
| 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) |
| 2026-05-12 00:00 |
01:46:48.70 |
+64:26:41.5 |
HIP 8315 |
25.58 |
| 2026-05-12 12:00 |
01:46:55.53 |
+64:27:14.1 |
HIP 8315 |
26.05 |
| 2026-05-13 00:00 |
01:47:02.33 |
+64:27:46.9 |
HIP 8315 |
26.56 |
| 2026-05-13 12:00 |
01:47:09.10 |
+64:28:20.0 |
HIP 8315 |
27.08 |
| 2026-05-14 00:00 |
01:47:15.86 |
+64:28:53.4 |
HIP 8315 |
27.64 |
| 2026-05-14 12:00 |
01:47:22.59 |
+64:29:27.1 |
HIP 8659 |
27.49 |
| 2026-05-15 00:00 |
01:47:29.30 |
+64:30:01.1 |
HIP 8659 |
26.71 |
| 2026-05-15 12:00 |
01:47:35.98 |
+64:30:35.3 |
HIP 8659 |
25.93 |
| 2026-05-16 00:00 |
01:47:42.64 |
+64:31:09.8 |
HIP 8659 |
25.17 |
| 2026-05-16 12:00 |
01:47:49.27 |
+64:31:44.6 |
HIP 8659 |
24.42 |
| 2026-05-17 00:00 |
01:47:55.87 |
+64:32:19.6 |
HIP 8659 |
23.69 |
| 2026-05-17 12:00 |
01:48:02.45 |
+64:32:55.0 |
HIP 8659 |
22.97 |
| 2026-05-18 00:00 |
01:48:09.00 |
+64:33:30.5 |
HIP 8659 |
22.27 |
| 2026-05-18 12:00 |
01:48:15.53 |
+64:34:06.4 |
HIP 8659 |
21.60 |
| 2026-05-19 00:00 |
01:48:22.02 |
+64:34:42.5 |
HIP 8659 |
20.94 |
| 2026-05-19 12:00 |
01:48:28.49 |
+64:35:18.9 |
HIP 8659 |
20.31 |
| 2026-05-20 00:00 |
01:48:34.93 |
+64:35:55.5 |
HIP 8659 |
19.71 |
| 2026-05-20 12:00 |
01:48:41.34 |
+64:36:32.4 |
HIP 8659 |
19.13 |
| 2026-05-21 00:00 |
01:48:47.72 |
+64:37:09.5 |
HIP 8659 |
18.59 |
| 2026-05-21 12:00 |
01:48:54.07 |
+64:37:46.9 |
HIP 8659 |
18.09 |
| 2026-05-22 00:00 |
01:49:00.39 |
+64:38:24.6 |
HIP 8659 |
17.62 |
| 2026-05-22 12:00 |
01:49:06.67 |
+64:39:02.5 |
HIP 8603 |
16.84 |
| 2026-05-23 00:00 |
01:49:12.93 |
+64:39:40.6 |
HIP 8603 |
15.91 |
| 2026-05-23 12:00 |
01:49:19.15 |
+64:40:19.0 |
HIP 8603 |
14.99 |
| 2026-05-24 00:00 |
01:49:25.34 |
+64:40:57.6 |
HIP 8603 |
14.07 |
| 2026-05-24 12:00 |
01:49:31.50 |
+64:41:36.4 |
HIP 8603 |
13.14 |
| 2026-05-25 00:00 |
01:49:37.63 |
+64:42:15.5 |
HIP 8603 |
12.22 |
| 2026-05-25 12:00 |
01:49:43.72 |
+64:42:54.8 |
HIP 8603 |
11.30 |
| 2026-05-26 00:00 |
01:49:49.78 |
+64:43:34.4 |
HIP 8603 |
10.37 |
| 2026-05-26 12:00 |
01:49:55.80 |
+64:44:14.2 |
HIP 8603 |
9.45 |
| 2026-05-27 00:00 |
01:50:01.79 |
+64:44:54.2 |
HIP 8603 |
8.53 |
| 2026-05-27 12:00 |
01:50:07.74 |
+64:45:34.4 |
HIP 8603 |
7.61 |
| 2026-05-28 00:00 |
01:50:13.66 |
+64:46:14.9 |
HIP 8603 |
6.68 |
| 2026-05-28 12:00 |
01:50:19.54 |
+64:46:55.5 |
HIP 8603 |
5.76 |
| 2026-05-29 00:00 |
01:50:25.39 |
+64:47:36.4 |
HIP 8603 |
4.85 |
| 2026-05-29 12:00 |
01:50:31.20 |
+64:48:17.6 |
HIP 8603 |
3.93 |
| 2026-05-30 00:00 |
01:50:36.97 |
+64:48:58.9 |
HIP 8603 |
3.02 |
| 2026-05-30 12:00 |
01:50:42.71 |
+64:49:40.4 |
HIP 8603 |
2.12 |
| 2026-05-31 00:00 |
01:50:48.40 |
+64:50:22.2 |
HIP 8603 |
1.27 |
| 2026-05-31 12:00 |
01:50:54.06 |
+64:51:04.2 |
HIP 8603 |
0.64 |
| 2026-06-01 00:00 |
01:50:59.68 |
+64:51:46.3 |
HIP 8603 |
0.96 |
| 2026-06-01 12:00 |
01:51:05.26 |
+64:52:28.7 |
HIP 8626 |
1.71 |
| 2026-06-02 00:00 |
01:51:10.80 |
+64:53:11.3 |
HIP 8632 |
1.74 |