C/2012 K6 (McNaught)
| Parameter |
Value |
| Designation |
C/2012 K6 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-05-21T11:03:28.212480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:10Z |
| Obs used |
1091 |
| NEO |
- |
| M1 |
8.900 |
| K1 |
7.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-12-31.0000000 |
| e |
0.99919878 |
| q (au) |
3.353032 |
| a (au) |
4184.883889 |
| i (deg) |
135.215103 |
| Ω (om, deg) |
206.898541 |
| ω (w, deg) |
338.826785 |
| M (ma, deg) |
0.000814 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.021 + 3.183\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.021 |
| n |
3.183 |
| gf |
0.997 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.993 |
| 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 |
| 2012-04-20 |
2013-05-20 |
+12.1573 |
-6.871 |
| 2013-06-02 |
2014-01-30 |
-1.7355 |
+0.738 |
| 2014-01-30 |
2015-04-09 |
-2.5207 |
+1.571 |
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 |
04:38:21.91 |
+61:38:21.0 |
HIP 21447 |
22.02 |
| 2026-02-03 12:00 |
04:38:17.04 |
+61:37:36.6 |
HIP 21447 |
21.08 |
| 2026-02-04 00:00 |
04:38:12.24 |
+61:36:52.1 |
HIP 21447 |
20.15 |
| 2026-02-04 12:00 |
04:38:07.52 |
+61:36:07.5 |
HIP 21447 |
19.22 |
| 2026-02-05 00:00 |
04:38:02.88 |
+61:35:22.8 |
HIP 21447 |
18.30 |
| 2026-02-05 12:00 |
04:37:58.32 |
+61:34:38.0 |
HIP 21447 |
17.38 |
| 2026-02-06 00:00 |
04:37:53.84 |
+61:33:53.1 |
HIP 21447 |
16.47 |
| 2026-02-06 12:00 |
04:37:49.44 |
+61:33:08.2 |
HIP 21447 |
15.56 |
| 2026-02-07 00:00 |
04:37:45.11 |
+61:32:23.2 |
HIP 21447 |
14.66 |
| 2026-02-07 12:00 |
04:37:40.86 |
+61:31:38.1 |
HIP 21447 |
13.77 |
| 2026-02-08 00:00 |
04:37:36.70 |
+61:30:53.0 |
HIP 21447 |
12.89 |
| 2026-02-08 12:00 |
04:37:32.61 |
+61:30:07.7 |
HIP 21447 |
12.01 |
| 2026-02-09 00:00 |
04:37:28.60 |
+61:29:22.5 |
HIP 21447 |
11.14 |
| 2026-02-09 12:00 |
04:37:24.67 |
+61:28:37.1 |
HIP 21447 |
10.29 |
| 2026-02-10 00:00 |
04:37:20.82 |
+61:27:51.8 |
HIP 21447 |
9.44 |
| 2026-02-10 12:00 |
04:37:17.05 |
+61:27:06.3 |
HIP 21447 |
8.62 |
| 2026-02-11 00:00 |
04:37:13.37 |
+61:26:20.9 |
HIP 21447 |
7.81 |
| 2026-02-11 12:00 |
04:37:09.76 |
+61:25:35.4 |
HIP 21447 |
7.02 |
| 2026-02-12 00:00 |
04:37:06.23 |
+61:24:49.8 |
HIP 21447 |
6.26 |
| 2026-02-12 12:00 |
04:37:02.78 |
+61:24:04.3 |
HIP 21447 |
5.55 |
| 2026-02-13 00:00 |
04:36:59.41 |
+61:23:18.7 |
HIP 21447 |
4.89 |
| 2026-02-13 12:00 |
04:36:56.12 |
+61:22:33.0 |
HIP 21447 |
4.32 |
| 2026-02-14 00:00 |
04:36:52.92 |
+61:21:47.4 |
HIP 21447 |
3.86 |
| 2026-02-14 12:00 |
04:36:49.79 |
+61:21:01.7 |
HIP 21447 |
3.56 |
| 2026-02-15 00:00 |
04:36:46.74 |
+61:20:16.0 |
HIP 21447 |
3.45 |
| 2026-02-15 12:00 |
04:36:43.78 |
+61:19:30.4 |
HIP 21447 |
3.55 |
| 2026-02-16 00:00 |
04:36:40.89 |
+61:18:44.7 |
HIP 21447 |
3.85 |
| 2026-02-16 12:00 |
04:36:38.09 |
+61:17:59.0 |
HIP 21447 |
4.30 |
| 2026-02-17 00:00 |
04:36:35.37 |
+61:17:13.3 |
HIP 21447 |
4.85 |
| 2026-02-17 12:00 |
04:36:32.72 |
+61:16:27.6 |
HIP 21447 |
5.47 |
| 2026-02-18 00:00 |
04:36:30.16 |
+61:15:41.9 |
HIP 21447 |
6.15 |
| 2026-02-18 12:00 |
04:36:27.68 |
+61:14:56.3 |
HIP 21447 |
6.85 |
| 2026-02-19 00:00 |
04:36:25.28 |
+61:14:10.6 |
HIP 21447 |
7.58 |
| 2026-02-19 12:00 |
04:36:22.96 |
+61:13:25.0 |
HIP 21447 |
8.33 |
| 2026-02-20 00:00 |
04:36:20.72 |
+61:12:39.4 |
HIP 21447 |
9.08 |
| 2026-02-20 12:00 |
04:36:18.56 |
+61:11:53.8 |
HIP 21447 |
9.85 |
| 2026-02-21 00:00 |
04:36:16.48 |
+61:11:08.3 |
HIP 21447 |
10.61 |
| 2026-02-21 12:00 |
04:36:14.48 |
+61:10:22.8 |
HIP 21447 |
11.39 |
| 2026-02-22 00:00 |
04:36:12.56 |
+61:09:37.3 |
HIP 21447 |
12.16 |
| 2026-02-22 12:00 |
04:36:10.73 |
+61:08:51.9 |
HIP 21447 |
12.93 |
| 2026-02-23 00:00 |
04:36:08.97 |
+61:08:06.6 |
HIP 21447 |
13.70 |
| 2026-02-23 12:00 |
04:36:07.29 |
+61:07:21.2 |
HIP 21447 |
14.48 |
| 2026-02-24 00:00 |
04:36:05.69 |
+61:06:36.0 |
HIP 21447 |
15.25 |