C/2007 T1 (McNaught)
| 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) |
| 2026-02-03 00:00 |
06:12:22.48 |
+54:52:06.3 |
HIP 29085 |
36.69 |
| 2026-02-03 12:00 |
06:12:18.15 |
+54:51:51.8 |
HIP 29085 |
36.09 |
| 2026-02-04 00:00 |
06:12:13.86 |
+54:51:37.2 |
HIP 29085 |
35.49 |
| 2026-02-04 12:00 |
06:12:09.60 |
+54:51:22.5 |
HIP 29085 |
34.91 |
| 2026-02-05 00:00 |
06:12:05.37 |
+54:51:07.5 |
HIP 29085 |
34.33 |
| 2026-02-05 12:00 |
06:12:01.19 |
+54:50:52.4 |
HIP 29085 |
33.77 |
| 2026-02-06 00:00 |
06:11:57.03 |
+54:50:37.1 |
HIP 29085 |
33.21 |
| 2026-02-06 12:00 |
06:11:52.92 |
+54:50:21.7 |
HIP 29085 |
32.66 |
| 2026-02-07 00:00 |
06:11:48.84 |
+54:50:06.1 |
HIP 29085 |
32.12 |
| 2026-02-07 12:00 |
06:11:44.79 |
+54:49:50.3 |
HIP 29085 |
31.58 |
| 2026-02-08 00:00 |
06:11:40.79 |
+54:49:34.4 |
HIP 29085 |
31.06 |
| 2026-02-08 12:00 |
06:11:36.82 |
+54:49:18.3 |
HIP 29085 |
30.55 |
| 2026-02-09 00:00 |
06:11:32.89 |
+54:49:02.1 |
HIP 29085 |
30.05 |
| 2026-02-09 12:00 |
06:11:28.99 |
+54:48:45.7 |
HIP 29085 |
29.55 |
| 2026-02-10 00:00 |
06:11:25.14 |
+54:48:29.1 |
HIP 29085 |
29.07 |
| 2026-02-10 12:00 |
06:11:21.32 |
+54:48:12.4 |
HIP 29085 |
28.60 |
| 2026-02-11 00:00 |
06:11:17.55 |
+54:47:55.5 |
HIP 29085 |
28.15 |
| 2026-02-11 12:00 |
06:11:13.81 |
+54:47:38.5 |
HIP 29085 |
27.70 |
| 2026-02-12 00:00 |
06:11:10.11 |
+54:47:21.4 |
HIP 29085 |
27.27 |
| 2026-02-12 12:00 |
06:11:06.45 |
+54:47:04.1 |
HIP 29085 |
26.84 |
| 2026-02-13 00:00 |
06:11:02.83 |
+54:46:46.6 |
HIP 29085 |
26.44 |
| 2026-02-13 12:00 |
06:10:59.25 |
+54:46:29.0 |
HIP 29085 |
26.04 |
| 2026-02-14 00:00 |
06:10:55.71 |
+54:46:11.3 |
HIP 29085 |
25.66 |
| 2026-02-14 12:00 |
06:10:52.21 |
+54:45:53.4 |
HIP 29085 |
25.29 |
| 2026-02-15 00:00 |
06:10:48.76 |
+54:45:35.4 |
HIP 29085 |
24.94 |
| 2026-02-15 12:00 |
06:10:45.34 |
+54:45:17.3 |
HIP 29085 |
24.60 |
| 2026-02-16 00:00 |
06:10:41.97 |
+54:44:59.0 |
HIP 29085 |
24.28 |
| 2026-02-16 12:00 |
06:10:38.63 |
+54:44:40.6 |
HIP 29085 |
23.97 |
| 2026-02-17 00:00 |
06:10:35.34 |
+54:44:22.1 |
HIP 29085 |
23.68 |
| 2026-02-17 12:00 |
06:10:32.10 |
+54:44:03.4 |
HIP 29085 |
23.41 |
| 2026-02-18 00:00 |
06:10:28.89 |
+54:43:44.6 |
HIP 29085 |
23.15 |
| 2026-02-18 12:00 |
06:10:25.73 |
+54:43:25.7 |
HIP 29085 |
22.91 |
| 2026-02-19 00:00 |
06:10:22.61 |
+54:43:06.7 |
HIP 29085 |
22.69 |
| 2026-02-19 12:00 |
06:10:19.53 |
+54:42:47.6 |
HIP 29085 |
22.48 |
| 2026-02-20 00:00 |
06:10:16.50 |
+54:42:28.3 |
HIP 29085 |
22.29 |
| 2026-02-20 12:00 |
06:10:13.51 |
+54:42:08.9 |
HIP 29085 |
22.12 |
| 2026-02-21 00:00 |
06:10:10.56 |
+54:41:49.5 |
HIP 29085 |
21.97 |
| 2026-02-21 12:00 |
06:10:07.66 |
+54:41:29.9 |
HIP 29085 |
21.84 |
| 2026-02-22 00:00 |
06:10:04.80 |
+54:41:10.2 |
HIP 29085 |
21.72 |
| 2026-02-22 12:00 |
06:10:01.98 |
+54:40:50.4 |
HIP 29085 |
21.62 |
| 2026-02-23 00:00 |
06:09:59.21 |
+54:40:30.4 |
HIP 29085 |
21.54 |
| 2026-02-23 12:00 |
06:09:56.49 |
+54:40:10.4 |
HIP 29085 |
21.48 |
| 2026-02-24 00:00 |
06:09:53.80 |
+54:39:50.3 |
HIP 29085 |
21.44 |