| 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) |
| 2026-05-12 00:00 |
02:41:42.26 |
+55:20:24.4 |
HIP 12575 |
8.49 |
| 2026-05-12 12:00 |
02:41:47.21 |
+55:20:36.8 |
HIP 12575 |
8.30 |
| 2026-05-13 00:00 |
02:41:52.14 |
+55:20:49.5 |
HIP 12575 |
8.18 |
| 2026-05-13 12:00 |
02:41:57.08 |
+55:21:02.3 |
HIP 12575 |
8.11 |
| 2026-05-14 00:00 |
02:42:02.00 |
+55:21:15.4 |
HIP 12575 |
8.11 |
| 2026-05-14 12:00 |
02:42:06.92 |
+55:21:28.7 |
HIP 12575 |
8.17 |
| 2026-05-15 00:00 |
02:42:11.83 |
+55:21:42.1 |
HIP 12575 |
8.29 |
| 2026-05-15 12:00 |
02:42:16.73 |
+55:21:55.8 |
HIP 12575 |
8.47 |
| 2026-05-16 00:00 |
02:42:21.63 |
+55:22:09.7 |
HIP 12575 |
8.70 |
| 2026-05-16 12:00 |
02:42:26.52 |
+55:22:23.8 |
HIP 12575 |
8.99 |
| 2026-05-17 00:00 |
02:42:31.40 |
+55:22:38.1 |
HIP 12575 |
9.32 |
| 2026-05-17 12:00 |
02:42:36.27 |
+55:22:52.6 |
HIP 12575 |
9.69 |
| 2026-05-18 00:00 |
02:42:41.13 |
+55:23:07.3 |
HIP 12575 |
10.09 |
| 2026-05-18 12:00 |
02:42:45.98 |
+55:23:22.2 |
HIP 12575 |
10.53 |
| 2026-05-19 00:00 |
02:42:50.82 |
+55:23:37.3 |
HIP 12575 |
11.00 |
| 2026-05-19 12:00 |
02:42:55.65 |
+55:23:52.6 |
HIP 12575 |
11.49 |
| 2026-05-20 00:00 |
02:43:00.47 |
+55:24:08.1 |
HIP 12575 |
12.00 |
| 2026-05-20 12:00 |
02:43:05.28 |
+55:24:23.8 |
HIP 12575 |
12.54 |
| 2026-05-21 00:00 |
02:43:10.08 |
+55:24:39.6 |
HIP 12575 |
13.09 |
| 2026-05-21 12:00 |
02:43:14.87 |
+55:24:55.7 |
HIP 12575 |
13.65 |
| 2026-05-22 00:00 |
02:43:19.65 |
+55:25:12.0 |
HIP 12575 |
14.22 |
| 2026-05-22 12:00 |
02:43:24.41 |
+55:25:28.4 |
HIP 12575 |
14.81 |
| 2026-05-23 00:00 |
02:43:29.16 |
+55:25:45.1 |
HIP 12575 |
15.41 |
| 2026-05-23 12:00 |
02:43:33.90 |
+55:26:01.9 |
HIP 12575 |
16.01 |
| 2026-05-24 00:00 |
02:43:38.63 |
+55:26:18.9 |
HIP 12575 |
16.62 |
| 2026-05-24 12:00 |
02:43:43.34 |
+55:26:36.1 |
HIP 12575 |
17.24 |
| 2026-05-25 00:00 |
02:43:48.04 |
+55:26:53.4 |
HIP 12575 |
17.87 |
| 2026-05-25 12:00 |
02:43:52.73 |
+55:27:11.0 |
HIP 12575 |
18.50 |
| 2026-05-26 00:00 |
02:43:57.40 |
+55:27:28.7 |
HIP 12816 |
18.27 |
| 2026-05-26 12:00 |
02:44:02.06 |
+55:27:46.6 |
HIP 12816 |
17.76 |
| 2026-05-27 00:00 |
02:44:06.70 |
+55:28:04.7 |
HIP 12816 |
17.25 |
| 2026-05-27 12:00 |
02:44:11.33 |
+55:28:23.0 |
HIP 12816 |
16.76 |
| 2026-05-28 00:00 |
02:44:15.95 |
+55:28:41.4 |
HIP 12816 |
16.28 |
| 2026-05-28 12:00 |
02:44:20.54 |
+55:29:00.0 |
HIP 12816 |
15.82 |
| 2026-05-29 00:00 |
02:44:25.13 |
+55:29:18.8 |
HIP 12816 |
15.38 |
| 2026-05-29 12:00 |
02:44:29.69 |
+55:29:37.7 |
HIP 12816 |
14.95 |
| 2026-05-30 00:00 |
02:44:34.24 |
+55:29:56.8 |
HIP 12816 |
14.55 |
| 2026-05-30 12:00 |
02:44:38.78 |
+55:30:16.1 |
HIP 12816 |
14.17 |
| 2026-05-31 00:00 |
02:44:43.30 |
+55:30:35.6 |
HIP 12816 |
13.81 |
| 2026-05-31 12:00 |
02:44:47.80 |
+55:30:55.2 |
HIP 12816 |
13.48 |
| 2026-06-01 00:00 |
02:44:52.28 |
+55:31:15.0 |
HIP 12816 |
13.17 |
| 2026-06-01 12:00 |
02:44:56.75 |
+55:31:34.9 |
HIP 12816 |
12.90 |
| 2026-06-02 00:00 |
02:45:01.20 |
+55:31:55.0 |
HIP 12816 |
12.65 |