| Parameter |
Value |
| Designation |
C/2007 T1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2007-12-12T12:43:02.167680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:12Z |
| Obs used |
321 |
| NEO |
- |
| M1 |
11.100 |
| K1 |
15.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2007-12-03.0000000 |
| e |
0.99975973 |
| q (au) |
0.968503 |
| a (au) |
4030.976593 |
| i (deg) |
117.642445 |
| Ω (om, deg) |
111.433284 |
| ω (w, deg) |
233.755132 |
| M (ma, deg) |
359.999963 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.423 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.423 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.980 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2007-10-09 |
2007-11-17 |
+26.4957 |
-3.984 |
| 2007-12-28 |
2008-03-01 |
+0.7703 |
-2.913 |
| 2008-03-01 |
2008-04-10 |
+33.3065 |
-10.740 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
06:08:37.21 |
+54:17:54.5 |
HIP 28841 |
30.08 |
| 2026-03-26 12:00 |
06:08:37.35 |
+54:17:31.9 |
HIP 28841 |
30.19 |
| 2026-03-27 00:00 |
06:08:37.55 |
+54:17:09.4 |
HIP 28841 |
30.31 |
| 2026-03-27 12:00 |
06:08:37.78 |
+54:16:46.9 |
HIP 28841 |
30.44 |
| 2026-03-28 00:00 |
06:08:38.07 |
+54:16:24.4 |
HIP 28841 |
30.57 |
| 2026-03-28 12:00 |
06:08:38.39 |
+54:16:02.0 |
HIP 28841 |
30.72 |
| 2026-03-29 00:00 |
06:08:38.77 |
+54:15:39.6 |
HIP 28841 |
30.88 |
| 2026-03-29 12:00 |
06:08:39.18 |
+54:15:17.2 |
HIP 28841 |
31.05 |
| 2026-03-30 00:00 |
06:08:39.65 |
+54:14:54.8 |
HIP 28841 |
31.23 |
| 2026-03-30 12:00 |
06:08:40.16 |
+54:14:32.5 |
HIP 28841 |
31.42 |
| 2026-03-31 00:00 |
06:08:40.71 |
+54:14:10.2 |
HIP 28841 |
31.62 |
| 2026-03-31 12:00 |
06:08:41.31 |
+54:13:47.9 |
HIP 28841 |
31.82 |
| 2026-04-01 00:00 |
06:08:41.95 |
+54:13:25.7 |
HIP 28841 |
32.04 |
| 2026-04-01 12:00 |
06:08:42.63 |
+54:13:03.5 |
HIP 28841 |
32.26 |
| 2026-04-02 00:00 |
06:08:43.36 |
+54:12:41.4 |
HIP 28841 |
32.50 |
| 2026-04-02 12:00 |
06:08:44.14 |
+54:12:19.2 |
HIP 28841 |
32.74 |
| 2026-04-03 00:00 |
06:08:44.96 |
+54:11:57.2 |
HIP 28841 |
32.99 |
| 2026-04-03 12:00 |
06:08:45.82 |
+54:11:35.1 |
HIP 28841 |
33.25 |
| 2026-04-04 00:00 |
06:08:46.73 |
+54:11:13.2 |
HIP 28841 |
33.52 |
| 2026-04-04 12:00 |
06:08:47.68 |
+54:10:51.2 |
HIP 28841 |
33.79 |
| 2026-04-05 00:00 |
06:08:48.67 |
+54:10:29.3 |
HIP 28841 |
34.08 |
| 2026-04-05 12:00 |
06:08:49.70 |
+54:10:07.5 |
HIP 29422 |
33.88 |
| 2026-04-06 00:00 |
06:08:50.78 |
+54:09:45.7 |
HIP 29422 |
33.54 |
| 2026-04-06 12:00 |
06:08:51.91 |
+54:09:24.0 |
HIP 29422 |
33.19 |
| 2026-04-07 00:00 |
06:08:53.07 |
+54:09:02.3 |
HIP 29422 |
32.84 |
| 2026-04-07 12:00 |
06:08:54.28 |
+54:08:40.7 |
HIP 29422 |
32.49 |
| 2026-04-08 00:00 |
06:08:55.53 |
+54:08:19.1 |
HIP 29422 |
32.14 |
| 2026-04-08 12:00 |
06:08:56.83 |
+54:07:57.6 |
HIP 29422 |
31.78 |
| 2026-04-09 00:00 |
06:08:58.16 |
+54:07:36.1 |
HIP 29422 |
31.41 |
| 2026-04-09 12:00 |
06:08:59.54 |
+54:07:14.8 |
HIP 29422 |
31.05 |
| 2026-04-10 00:00 |
06:09:00.96 |
+54:06:53.4 |
HIP 29422 |
30.68 |
| 2026-04-10 12:00 |
06:09:02.42 |
+54:06:32.2 |
HIP 29422 |
30.31 |
| 2026-04-11 00:00 |
06:09:03.93 |
+54:06:11.0 |
HIP 29422 |
29.93 |
| 2026-04-11 12:00 |
06:09:05.47 |
+54:05:49.9 |
HIP 29422 |
29.55 |
| 2026-04-12 00:00 |
06:09:07.06 |
+54:05:28.8 |
HIP 29422 |
29.17 |
| 2026-04-12 12:00 |
06:09:08.69 |
+54:05:07.8 |
HIP 29422 |
28.78 |
| 2026-04-13 00:00 |
06:09:10.36 |
+54:04:46.9 |
HIP 29422 |
28.39 |
| 2026-04-13 12:00 |
06:09:12.07 |
+54:04:26.1 |
HIP 29422 |
28.00 |
| 2026-04-14 00:00 |
06:09:13.82 |
+54:04:05.3 |
HIP 29422 |
27.60 |
| 2026-04-14 12:00 |
06:09:15.61 |
+54:03:44.6 |
HIP 29422 |
27.20 |
| 2026-04-15 00:00 |
06:09:17.44 |
+54:03:24.0 |
HIP 29422 |
26.79 |
| 2026-04-15 12:00 |
06:09:19.32 |
+54:03:03.5 |
HIP 29422 |
26.38 |
| 2026-04-16 00:00 |
06:09:21.23 |
+54:02:43.0 |
HIP 29422 |
25.97 |