| Parameter |
Value |
| Designation |
C/2009 R1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-07-02T16:16:32.168640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:34Z |
| Obs used |
751 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-04-11.0000000 |
| e |
1.00041320 |
| q (au) |
0.405087 |
| a (au) |
-980.359275 |
| i (deg) |
77.030765 |
| Ω (om, deg) |
322.622663 |
| ω (w, deg) |
130.693103 |
| M (ma, deg) |
-0.002655 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.751 + 4.547\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.751 |
| n |
4.547 |
| gf |
1.000 |
| gb |
-0.800 |
| k |
0.800 |
| 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 |
| 2009-07-20 |
2010-01-09 |
+20.6267 |
-13.127 |
| 2010-01-09 |
2010-06-05 |
-5.1167 |
-0.996 |
| 2010-06-05 |
2010-06-29 |
-1.4652 |
-1.713 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
23:23:45.21 |
-74:11:09.5 |
HIP 115739 |
24.69 |
| 2026-06-01 12:00 |
23:23:46.98 |
-74:11:53.6 |
HIP 115739 |
25.26 |
| 2026-06-02 00:00 |
23:23:48.67 |
-74:12:37.9 |
HIP 115739 |
25.83 |
| 2026-06-02 12:00 |
23:23:50.26 |
-74:13:22.3 |
HIP 115739 |
26.42 |
| 2026-06-03 00:00 |
23:23:51.77 |
-74:14:06.8 |
HIP 115739 |
27.03 |
| 2026-06-03 12:00 |
23:23:53.18 |
-74:14:51.4 |
HIP 115072 |
27.23 |
| 2026-06-04 00:00 |
23:23:54.49 |
-74:15:36.2 |
HIP 115072 |
26.86 |
| 2026-06-04 12:00 |
23:23:55.72 |
-74:16:21.0 |
HIP 115072 |
26.50 |
| 2026-06-05 00:00 |
23:23:56.85 |
-74:17:06.0 |
HIP 115072 |
26.15 |
| 2026-06-05 12:00 |
23:23:57.89 |
-74:17:51.0 |
HIP 115072 |
25.82 |
| 2026-06-06 00:00 |
23:23:58.83 |
-74:18:36.2 |
HIP 115072 |
25.49 |
| 2026-06-06 12:00 |
23:23:59.69 |
-74:19:21.5 |
HIP 115072 |
25.18 |
| 2026-06-07 00:00 |
23:24:00.44 |
-74:20:06.8 |
HIP 115072 |
24.87 |
| 2026-06-07 12:00 |
23:24:01.10 |
-74:20:52.2 |
HIP 115072 |
24.59 |
| 2026-06-08 00:00 |
23:24:01.67 |
-74:21:37.8 |
HIP 115072 |
24.31 |
| 2026-06-08 12:00 |
23:24:02.14 |
-74:22:23.4 |
HIP 115072 |
24.05 |
| 2026-06-09 00:00 |
23:24:02.52 |
-74:23:09.1 |
HIP 115072 |
23.80 |
| 2026-06-09 12:00 |
23:24:02.80 |
-74:23:54.8 |
HIP 115072 |
23.57 |
| 2026-06-10 00:00 |
23:24:02.98 |
-74:24:40.7 |
HIP 115072 |
23.36 |
| 2026-06-10 12:00 |
23:24:03.07 |
-74:25:26.6 |
HIP 115072 |
23.16 |
| 2026-06-11 00:00 |
23:24:03.06 |
-74:26:12.5 |
HIP 115072 |
22.98 |
| 2026-06-11 12:00 |
23:24:02.95 |
-74:26:58.6 |
HIP 115072 |
22.82 |
| 2026-06-12 00:00 |
23:24:02.74 |
-74:27:44.7 |
HIP 115072 |
22.68 |
| 2026-06-12 12:00 |
23:24:02.44 |
-74:28:30.8 |
HIP 115072 |
22.55 |
| 2026-06-13 00:00 |
23:24:02.04 |
-74:29:17.0 |
HIP 115072 |
22.44 |
| 2026-06-13 12:00 |
23:24:01.54 |
-74:30:03.3 |
HIP 115072 |
22.36 |
| 2026-06-14 00:00 |
23:24:00.94 |
-74:30:49.6 |
HIP 115072 |
22.29 |
| 2026-06-14 12:00 |
23:24:00.24 |
-74:31:35.9 |
HIP 115072 |
22.24 |
| 2026-06-15 00:00 |
23:23:59.45 |
-74:32:22.3 |
HIP 115072 |
22.22 |
| 2026-06-15 12:00 |
23:23:58.55 |
-74:33:08.7 |
HIP 115072 |
22.21 |
| 2026-06-16 00:00 |
23:23:57.56 |
-74:33:55.2 |
HIP 115072 |
22.22 |
| 2026-06-16 12:00 |
23:23:56.46 |
-74:34:41.6 |
HIP 115072 |
22.26 |
| 2026-06-17 00:00 |
23:23:55.27 |
-74:35:28.1 |
HIP 115072 |
22.31 |
| 2026-06-17 12:00 |
23:23:53.97 |
-74:36:14.6 |
HIP 115072 |
22.39 |
| 2026-06-18 00:00 |
23:23:52.58 |
-74:37:01.2 |
HIP 115072 |
22.49 |
| 2026-06-18 12:00 |
23:23:51.09 |
-74:37:47.7 |
HIP 115072 |
22.61 |
| 2026-06-19 00:00 |
23:23:49.49 |
-74:38:34.2 |
HIP 115072 |
22.74 |
| 2026-06-19 12:00 |
23:23:47.80 |
-74:39:20.8 |
HIP 115072 |
22.90 |
| 2026-06-20 00:00 |
23:23:46.00 |
-74:40:07.3 |
HIP 115072 |
23.08 |
| 2026-06-20 12:00 |
23:23:44.11 |
-74:40:53.8 |
HIP 115072 |
23.28 |
| 2026-06-21 00:00 |
23:23:42.11 |
-74:41:40.4 |
HIP 115072 |
23.49 |
| 2026-06-21 12:00 |
23:23:40.02 |
-74:42:26.9 |
HIP 115072 |
23.73 |
| 2026-06-22 00:00 |
23:23:37.82 |
-74:43:13.4 |
HIP 115072 |
23.98 |