| Parameter |
Value |
| Designation |
C/2007 E2 (Lovejoy) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2007-03-27T12:01:31.946880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:05Z |
| Obs used |
1648 |
| NEO |
- |
| M1 |
10.300 |
| K1 |
17.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2007-05-15.0000000 |
| e |
0.99917565 |
| q (au) |
1.092938 |
| a (au) |
1325.822845 |
| i (deg) |
95.882901 |
| Ω (om, deg) |
232.431837 |
| ω (w, deg) |
340.533777 |
| M (ma, deg) |
0.000990 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.262 + 3.304\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.262 |
| n |
3.304 |
| gf |
1.000 |
| gb |
-0.728 |
| 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 |
| 2007-03-27 |
2007-08-23 |
+7.4238 |
-2.181 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
02:34:15.36 |
+55:18:23.2 |
HIP 11850 |
11.31 |
| 2026-03-26 12:00 |
02:34:19.47 |
+55:18:12.9 |
HIP 11850 |
11.91 |
| 2026-03-27 00:00 |
02:34:23.61 |
+55:18:02.9 |
HIP 11850 |
12.51 |
| 2026-03-27 12:00 |
02:34:27.78 |
+55:17:53.1 |
HIP 11850 |
13.12 |
| 2026-03-28 00:00 |
02:34:31.96 |
+55:17:43.6 |
HIP 11850 |
13.73 |
| 2026-03-28 12:00 |
02:34:36.17 |
+55:17:34.3 |
HIP 11850 |
14.35 |
| 2026-03-29 00:00 |
02:34:40.40 |
+55:17:25.2 |
HIP 11850 |
14.97 |
| 2026-03-29 12:00 |
02:34:44.65 |
+55:17:16.5 |
HIP 11850 |
15.59 |
| 2026-03-30 00:00 |
02:34:48.92 |
+55:17:08.0 |
HIP 11850 |
16.21 |
| 2026-03-30 12:00 |
02:34:53.21 |
+55:16:59.7 |
HIP 11850 |
16.84 |
| 2026-03-31 00:00 |
02:34:57.53 |
+55:16:51.7 |
HIP 11850 |
17.46 |
| 2026-03-31 12:00 |
02:35:01.86 |
+55:16:43.9 |
HIP 11850 |
18.09 |
| 2026-04-01 00:00 |
02:35:06.22 |
+55:16:36.4 |
HIP 11850 |
18.73 |
| 2026-04-01 12:00 |
02:35:10.59 |
+55:16:29.2 |
HIP 11850 |
19.36 |
| 2026-04-02 00:00 |
02:35:14.98 |
+55:16:22.2 |
HIP 11850 |
20.00 |
| 2026-04-02 12:00 |
02:35:19.39 |
+55:16:15.4 |
HIP 11850 |
20.63 |
| 2026-04-03 00:00 |
02:35:23.82 |
+55:16:09.0 |
HIP 11850 |
21.27 |
| 2026-04-03 12:00 |
02:35:28.27 |
+55:16:02.7 |
HIP 11850 |
21.92 |
| 2026-04-04 00:00 |
02:35:32.74 |
+55:15:56.7 |
HIP 11850 |
22.56 |
| 2026-04-04 12:00 |
02:35:37.22 |
+55:15:51.0 |
HIP 11850 |
23.21 |
| 2026-04-05 00:00 |
02:35:41.73 |
+55:15:45.5 |
HIP 11850 |
23.85 |
| 2026-04-05 12:00 |
02:35:46.25 |
+55:15:40.3 |
HIP 11850 |
24.50 |
| 2026-04-06 00:00 |
02:35:50.79 |
+55:15:35.4 |
HIP 11850 |
25.15 |
| 2026-04-06 12:00 |
02:35:55.34 |
+55:15:30.7 |
HIP 11850 |
25.81 |
| 2026-04-07 00:00 |
02:35:59.91 |
+55:15:26.2 |
HIP 11850 |
26.46 |
| 2026-04-07 12:00 |
02:36:04.50 |
+55:15:22.0 |
HIP 11850 |
27.12 |
| 2026-04-08 00:00 |
02:36:09.10 |
+55:15:18.1 |
HIP 11850 |
27.78 |
| 2026-04-08 12:00 |
02:36:13.72 |
+55:15:14.4 |
HIP 11850 |
28.44 |
| 2026-04-09 00:00 |
02:36:18.35 |
+55:15:10.9 |
HIP 11850 |
29.10 |
| 2026-04-09 12:00 |
02:36:23.00 |
+55:15:07.7 |
HIP 11850 |
29.76 |
| 2026-04-10 00:00 |
02:36:27.67 |
+55:15:04.8 |
HIP 11850 |
30.42 |
| 2026-04-10 12:00 |
02:36:32.35 |
+55:15:02.1 |
HIP 11850 |
31.09 |
| 2026-04-11 00:00 |
02:36:37.04 |
+55:14:59.7 |
HIP 11850 |
31.76 |
| 2026-04-11 12:00 |
02:36:41.75 |
+55:14:57.5 |
HIP 11850 |
32.42 |
| 2026-04-12 00:00 |
02:36:46.47 |
+55:14:55.6 |
HIP 11850 |
33.09 |
| 2026-04-12 12:00 |
02:36:51.20 |
+55:14:53.9 |
HIP 11850 |
33.76 |
| 2026-04-13 00:00 |
02:36:55.95 |
+55:14:52.5 |
HIP 11850 |
34.44 |
| 2026-04-13 12:00 |
02:37:00.71 |
+55:14:51.4 |
HIP 12325 |
34.34 |
| 2026-04-14 00:00 |
02:37:05.48 |
+55:14:50.4 |
HIP 12325 |
34.08 |
| 2026-04-14 12:00 |
02:37:10.26 |
+55:14:49.8 |
HIP 12325 |
33.82 |
| 2026-04-15 00:00 |
02:37:15.06 |
+55:14:49.4 |
HIP 12325 |
33.57 |
| 2026-04-15 12:00 |
02:37:19.86 |
+55:14:49.2 |
HIP 12325 |
33.32 |
| 2026-04-16 00:00 |
02:37:24.68 |
+55:14:49.3 |
HIP 12325 |
33.09 |