| Parameter |
Value |
| Designation |
C/2007 E1 (Garradd) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2007-05-23T19:56:03.209280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:05Z |
| Obs used |
1017 |
| NEO |
- |
| M1 |
13.900 |
| K1 |
9.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2007-05-21.0000000 |
| e |
0.98021742 |
| q (au) |
1.285863 |
| a (au) |
64.999734 |
| i (deg) |
174.393993 |
| Ω (om, deg) |
153.826639 |
| ω (w, deg) |
7.102013 |
| M (ma, deg) |
359.994676 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.954 + 4.197\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.954 |
| n |
4.197 |
| gf |
0.997 |
| gb |
-0.945 |
| k |
1.000 |
| 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 |
| 2007-03-13 |
2007-05-20 |
+25.1520 |
-4.738 |
| 2007-05-26 |
2007-12-27 |
+6.4550 |
-2.958 |
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 |
23:05:39.01 |
-04:39:19.0 |
HIP 113896 |
26.74 |
| 2026-03-26 12:00 |
23:05:41.69 |
-04:39:02.1 |
HIP 113896 |
27.46 |
| 2026-03-27 00:00 |
23:05:44.36 |
-04:38:45.2 |
HIP 113896 |
28.18 |
| 2026-03-27 12:00 |
23:05:47.02 |
-04:38:28.4 |
HIP 113896 |
28.90 |
| 2026-03-28 00:00 |
23:05:49.68 |
-04:38:11.7 |
HIP 114118 |
29.17 |
| 2026-03-28 12:00 |
23:05:52.32 |
-04:37:55.0 |
HIP 114118 |
28.63 |
| 2026-03-29 00:00 |
23:05:54.96 |
-04:37:38.4 |
HIP 114118 |
28.11 |
| 2026-03-29 12:00 |
23:05:57.58 |
-04:37:21.8 |
HIP 114118 |
27.59 |
| 2026-03-30 00:00 |
23:06:00.20 |
-04:37:05.2 |
HIP 114118 |
27.09 |
| 2026-03-30 12:00 |
23:06:02.80 |
-04:36:48.7 |
HIP 114118 |
26.59 |
| 2026-03-31 00:00 |
23:06:05.39 |
-04:36:32.3 |
HIP 114118 |
26.11 |
| 2026-03-31 12:00 |
23:06:07.98 |
-04:36:15.9 |
HIP 114120 |
25.64 |
| 2026-04-01 00:00 |
23:06:10.55 |
-04:35:59.6 |
HIP 114120 |
25.18 |
| 2026-04-01 12:00 |
23:06:13.11 |
-04:35:43.4 |
HIP 114120 |
24.73 |
| 2026-04-02 00:00 |
23:06:15.66 |
-04:35:27.2 |
HIP 114120 |
24.29 |
| 2026-04-02 12:00 |
23:06:18.21 |
-04:35:11.0 |
HIP 114120 |
23.87 |
| 2026-04-03 00:00 |
23:06:20.73 |
-04:34:55.0 |
HIP 114120 |
23.46 |
| 2026-04-03 12:00 |
23:06:23.25 |
-04:34:39.0 |
HIP 114120 |
23.07 |
| 2026-04-04 00:00 |
23:06:25.76 |
-04:34:23.0 |
HIP 114120 |
22.69 |
| 2026-04-04 12:00 |
23:06:28.25 |
-04:34:07.2 |
HIP 114120 |
22.32 |
| 2026-04-05 00:00 |
23:06:30.73 |
-04:33:51.3 |
HIP 114120 |
21.98 |
| 2026-04-05 12:00 |
23:06:33.20 |
-04:33:35.6 |
HIP 114120 |
21.65 |
| 2026-04-06 00:00 |
23:06:35.66 |
-04:33:19.9 |
HIP 114120 |
21.33 |
| 2026-04-06 12:00 |
23:06:38.11 |
-04:33:04.3 |
HIP 114120 |
21.04 |
| 2026-04-07 00:00 |
23:06:40.54 |
-04:32:48.8 |
HIP 114120 |
20.76 |
| 2026-04-07 12:00 |
23:06:42.96 |
-04:32:33.3 |
HIP 114120 |
20.50 |
| 2026-04-08 00:00 |
23:06:45.37 |
-04:32:18.0 |
HIP 114120 |
20.27 |
| 2026-04-08 12:00 |
23:06:47.76 |
-04:32:02.6 |
HIP 114120 |
20.05 |
| 2026-04-09 00:00 |
23:06:50.14 |
-04:31:47.4 |
HIP 114120 |
19.85 |
| 2026-04-09 12:00 |
23:06:52.51 |
-04:31:32.2 |
HIP 114120 |
19.67 |
| 2026-04-10 00:00 |
23:06:54.86 |
-04:31:17.2 |
HIP 114120 |
19.51 |
| 2026-04-10 12:00 |
23:06:57.20 |
-04:31:02.2 |
HIP 114120 |
19.37 |
| 2026-04-11 00:00 |
23:06:59.53 |
-04:30:47.2 |
HIP 114120 |
19.25 |
| 2026-04-11 12:00 |
23:07:01.84 |
-04:30:32.4 |
HIP 114120 |
19.15 |
| 2026-04-12 00:00 |
23:07:04.14 |
-04:30:17.6 |
HIP 114120 |
19.07 |
| 2026-04-12 12:00 |
23:07:06.42 |
-04:30:03.0 |
HIP 114120 |
19.01 |
| 2026-04-13 00:00 |
23:07:08.69 |
-04:29:48.4 |
HIP 114120 |
18.97 |
| 2026-04-13 12:00 |
23:07:10.94 |
-04:29:33.9 |
HIP 114120 |
18.96 |
| 2026-04-14 00:00 |
23:07:13.18 |
-04:29:19.5 |
HIP 114120 |
18.96 |
| 2026-04-14 12:00 |
23:07:15.40 |
-04:29:05.1 |
HIP 114120 |
18.98 |
| 2026-04-15 00:00 |
23:07:17.60 |
-04:28:50.9 |
HIP 114120 |
19.02 |
| 2026-04-15 12:00 |
23:07:19.80 |
-04:28:36.8 |
HIP 114120 |
19.07 |
| 2026-04-16 00:00 |
23:07:21.97 |
-04:28:22.7 |
HIP 114120 |
19.15 |