| Parameter |
Value |
| Designation |
C/2005 E2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2006-02-23T11:21:44.352000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:47Z |
| Obs used |
1317 |
| NEO |
- |
| M1 |
9.200 |
| K1 |
7.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2006-05-09.0000000 |
| e |
1.00013891 |
| q (au) |
1.519579 |
| a (au) |
-10939.545227 |
| i (deg) |
16.988338 |
| Ω (om, deg) |
347.847398 |
| ω (w, deg) |
39.966443 |
| M (ma, deg) |
0.000064 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.500 + 2.795\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.500 |
| n |
2.795 |
| gf |
1.000 |
| gb |
-0.592 |
| k |
1.000 |
| 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 |
| 2005-03-12 |
2006-02-23 |
-0.0274 |
-0.832 |
| 2006-02-23 |
2006-05-02 |
-34.1608 |
+5.629 |
| 2006-05-02 |
2006-10-31 |
+10.7803 |
-5.797 |
| 2006-10-31 |
2007-03-17 |
-2.8233 |
+2.023 |
| 2007-03-17 |
2008-03-02 |
+3.2327 |
-2.351 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
12:09:58.57 |
-06:33:41.2 |
HIP 59402 |
17.42 |
| 2026-09-20 12:00 |
12:10:01.24 |
-06:33:58.6 |
HIP 59402 |
16.77 |
| 2026-09-21 00:00 |
12:10:03.91 |
-06:34:16.0 |
HIP 59402 |
16.12 |
| 2026-09-21 12:00 |
12:10:06.58 |
-06:34:33.4 |
HIP 59402 |
15.48 |
| 2026-09-22 00:00 |
12:10:09.25 |
-06:34:50.9 |
HIP 59402 |
14.85 |
| 2026-09-22 12:00 |
12:10:11.92 |
-06:35:08.5 |
HIP 59402 |
14.23 |
| 2026-09-23 00:00 |
12:10:14.60 |
-06:35:26.1 |
HIP 59402 |
13.62 |
| 2026-09-23 12:00 |
12:10:17.27 |
-06:35:43.7 |
HIP 59402 |
13.02 |
| 2026-09-24 00:00 |
12:10:19.95 |
-06:36:01.3 |
HIP 59402 |
12.43 |
| 2026-09-24 12:00 |
12:10:22.63 |
-06:36:19.0 |
HIP 59402 |
11.86 |
| 2026-09-25 00:00 |
12:10:25.30 |
-06:36:36.7 |
HIP 59402 |
11.30 |
| 2026-09-25 12:00 |
12:10:27.98 |
-06:36:54.5 |
HIP 59402 |
10.77 |
| 2026-09-26 00:00 |
12:10:30.66 |
-06:37:12.3 |
HIP 59402 |
10.26 |
| 2026-09-26 12:00 |
12:10:33.33 |
-06:37:30.1 |
HIP 59402 |
9.78 |
| 2026-09-27 00:00 |
12:10:36.01 |
-06:37:48.0 |
HIP 59402 |
9.33 |
| 2026-09-27 12:00 |
12:10:38.68 |
-06:38:05.8 |
HIP 59402 |
8.92 |
| 2026-09-28 00:00 |
12:10:41.36 |
-06:38:23.8 |
HIP 59402 |
8.55 |
| 2026-09-28 12:00 |
12:10:44.03 |
-06:38:41.7 |
HIP 59402 |
8.23 |
| 2026-09-29 00:00 |
12:10:46.71 |
-06:38:59.7 |
HIP 59402 |
7.97 |
| 2026-09-29 12:00 |
12:10:49.38 |
-06:39:17.7 |
HIP 59402 |
7.76 |
| 2026-09-30 00:00 |
12:10:52.05 |
-06:39:35.7 |
HIP 59402 |
7.62 |
| 2026-09-30 12:00 |
12:10:54.72 |
-06:39:53.7 |
HIP 59402 |
7.55 |
| 2026-10-01 00:00 |
12:10:57.39 |
-06:40:11.8 |
HIP 59402 |
7.55 |
| 2026-10-01 12:00 |
12:11:00.06 |
-06:40:29.9 |
HIP 59402 |
7.62 |
| 2026-10-02 00:00 |
12:11:02.72 |
-06:40:48.0 |
HIP 59402 |
7.75 |
| 2026-10-02 12:00 |
12:11:05.38 |
-06:41:06.1 |
HIP 59402 |
7.96 |
| 2026-10-03 00:00 |
12:11:08.04 |
-06:41:24.3 |
HIP 59402 |
8.22 |
| 2026-10-03 12:00 |
12:11:10.70 |
-06:41:42.4 |
HIP 59402 |
8.53 |
| 2026-10-04 00:00 |
12:11:13.36 |
-06:42:00.6 |
HIP 59402 |
8.90 |
| 2026-10-04 12:00 |
12:11:16.01 |
-06:42:18.8 |
HIP 59402 |
9.31 |
| 2026-10-05 00:00 |
12:11:18.66 |
-06:42:37.0 |
HIP 59402 |
9.75 |
| 2026-10-05 12:00 |
12:11:21.30 |
-06:42:55.2 |
HIP 59402 |
10.23 |
| 2026-10-06 00:00 |
12:11:23.95 |
-06:43:13.5 |
HIP 59402 |
10.73 |
| 2026-10-06 12:00 |
12:11:26.59 |
-06:43:31.7 |
HIP 59402 |
11.26 |
| 2026-10-07 00:00 |
12:11:29.22 |
-06:43:50.0 |
HIP 59402 |
11.81 |
| 2026-10-07 12:00 |
12:11:31.85 |
-06:44:08.2 |
HIP 59402 |
12.37 |
| 2026-10-08 00:00 |
12:11:34.48 |
-06:44:26.5 |
HIP 59402 |
12.95 |
| 2026-10-08 12:00 |
12:11:37.11 |
-06:44:44.8 |
HIP 59402 |
13.54 |
| 2026-10-09 00:00 |
12:11:39.72 |
-06:45:03.1 |
HIP 59402 |
14.15 |
| 2026-10-09 12:00 |
12:11:42.34 |
-06:45:21.3 |
HIP 59402 |
14.76 |
| 2026-10-10 00:00 |
12:11:44.95 |
-06:45:39.6 |
HIP 59402 |
15.39 |
| 2026-10-10 12:00 |
12:11:47.55 |
-06:45:57.9 |
HIP 59507 |
15.64 |
| 2026-10-11 00:00 |
12:11:50.15 |
-06:46:16.2 |
HIP 59507 |
15.10 |