| Parameter |
Value |
| Designation |
C/2011 W3 (Lovejoy) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-12-16T00:17:00.297600Z |
| Orbit solution date (soln_date, UTC) |
2012-06-04T12:31:54Z |
| Obs used |
123 |
| NEO |
- |
| M1 |
15.300 |
| K1 |
9.300 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-12-06.0000000 |
| e |
0.99992942 |
| q (au) |
0.005554 |
| a (au) |
78.682940 |
| i (deg) |
134.355811 |
| Ω (om, deg) |
326.369147 |
| ω (w, deg) |
53.509212 |
| M (ma, deg) |
359.985862 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.974 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.974 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
| 2011-11-27 |
2011-12-13 |
+6.4650 |
+3.679 |
| 2011-12-13 |
2011-12-15 |
-5.1086 |
-3.970 |
| 2011-12-16 |
2011-12-21 |
-9.5415 |
-11.600 |
| 2011-12-21 |
2012-01-31 |
+3.0683 |
-4.819 |
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 |
06:54:59.02 |
-11:22:43.3 |
HIP 33336 |
17.72 |
| 2026-09-20 12:00 |
06:54:59.92 |
-11:23:14.1 |
HIP 33336 |
17.26 |
| 2026-09-21 00:00 |
06:55:00.79 |
-11:23:44.9 |
HIP 33336 |
16.81 |
| 2026-09-21 12:00 |
06:55:01.64 |
-11:24:15.7 |
HIP 33336 |
16.37 |
| 2026-09-22 00:00 |
06:55:02.45 |
-11:24:46.5 |
HIP 33336 |
15.95 |
| 2026-09-22 12:00 |
06:55:03.23 |
-11:25:17.4 |
HIP 33336 |
15.54 |
| 2026-09-23 00:00 |
06:55:03.99 |
-11:25:48.4 |
HIP 33336 |
15.14 |
| 2026-09-23 12:00 |
06:55:04.71 |
-11:26:19.3 |
HIP 33336 |
14.77 |
| 2026-09-24 00:00 |
06:55:05.40 |
-11:26:50.3 |
HIP 33336 |
14.41 |
| 2026-09-24 12:00 |
06:55:06.06 |
-11:27:21.3 |
HIP 33336 |
14.06 |
| 2026-09-25 00:00 |
06:55:06.69 |
-11:27:52.4 |
HIP 33336 |
13.74 |
| 2026-09-25 12:00 |
06:55:07.29 |
-11:28:23.5 |
HIP 33336 |
13.44 |
| 2026-09-26 00:00 |
06:55:07.86 |
-11:28:54.6 |
HIP 33336 |
13.16 |
| 2026-09-26 12:00 |
06:55:08.40 |
-11:29:25.7 |
HIP 33336 |
12.91 |
| 2026-09-27 00:00 |
06:55:08.91 |
-11:29:56.8 |
HIP 33336 |
12.68 |
| 2026-09-27 12:00 |
06:55:09.39 |
-11:30:27.9 |
HIP 33336 |
12.47 |
| 2026-09-28 00:00 |
06:55:09.83 |
-11:30:59.1 |
HIP 33336 |
12.30 |
| 2026-09-28 12:00 |
06:55:10.25 |
-11:31:30.3 |
HIP 33336 |
12.15 |
| 2026-09-29 00:00 |
06:55:10.63 |
-11:32:01.4 |
HIP 33336 |
12.03 |
| 2026-09-29 12:00 |
06:55:10.98 |
-11:32:32.6 |
HIP 33336 |
11.94 |
| 2026-09-30 00:00 |
06:55:11.31 |
-11:33:03.8 |
HIP 33336 |
11.88 |
| 2026-09-30 12:00 |
06:55:11.60 |
-11:33:35.0 |
HIP 33336 |
11.85 |
| 2026-10-01 00:00 |
06:55:11.85 |
-11:34:06.2 |
HIP 33336 |
11.85 |
| 2026-10-01 12:00 |
06:55:12.08 |
-11:34:37.4 |
HIP 33247 |
11.86 |
| 2026-10-02 00:00 |
06:55:12.28 |
-11:35:08.6 |
HIP 33247 |
11.36 |
| 2026-10-02 12:00 |
06:55:12.44 |
-11:35:39.8 |
HIP 33247 |
10.86 |
| 2026-10-03 00:00 |
06:55:12.57 |
-11:36:11.0 |
HIP 33247 |
10.37 |
| 2026-10-03 12:00 |
06:55:12.67 |
-11:36:42.1 |
HIP 33247 |
9.87 |
| 2026-10-04 00:00 |
06:55:12.74 |
-11:37:13.3 |
HIP 33247 |
9.37 |
| 2026-10-04 12:00 |
06:55:12.78 |
-11:37:44.4 |
HIP 33247 |
8.88 |
| 2026-10-05 00:00 |
06:55:12.78 |
-11:38:15.6 |
HIP 33247 |
8.38 |
| 2026-10-05 12:00 |
06:55:12.76 |
-11:38:46.7 |
HIP 33247 |
7.89 |
| 2026-10-06 00:00 |
06:55:12.70 |
-11:39:17.8 |
HIP 33247 |
7.40 |
| 2026-10-06 12:00 |
06:55:12.60 |
-11:39:48.8 |
HIP 33247 |
6.90 |
| 2026-10-07 00:00 |
06:55:12.48 |
-11:40:19.8 |
HIP 33247 |
6.41 |
| 2026-10-07 12:00 |
06:55:12.32 |
-11:40:50.9 |
HIP 33247 |
5.93 |
| 2026-10-08 00:00 |
06:55:12.14 |
-11:41:21.8 |
HIP 33247 |
5.44 |
| 2026-10-08 12:00 |
06:55:11.92 |
-11:41:52.8 |
HIP 33247 |
4.96 |
| 2026-10-09 00:00 |
06:55:11.66 |
-11:42:23.7 |
HIP 33247 |
4.48 |
| 2026-10-09 12:00 |
06:55:11.38 |
-11:42:54.5 |
HIP 33247 |
4.01 |
| 2026-10-10 00:00 |
06:55:11.06 |
-11:43:25.4 |
HIP 33247 |
3.55 |
| 2026-10-10 12:00 |
06:55:10.71 |
-11:43:56.1 |
HIP 33247 |
3.10 |
| 2026-10-11 00:00 |
06:55:10.33 |
-11:44:26.9 |
HIP 33247 |
2.67 |