| 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 |
1.000 |
| 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 |
+25.1523 |
-4.738 |
| 2007-05-26 |
2007-12-27 |
+6.4556 |
-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) |
| 2026-09-20 00:00 |
23:01:38.22 |
-05:02:00.2 |
HIP 113686 |
19.38 |
| 2026-09-20 12:00 |
23:01:35.11 |
-05:02:20.0 |
HIP 113686 |
19.66 |
| 2026-09-21 00:00 |
23:01:32.01 |
-05:02:39.8 |
HIP 113686 |
19.97 |
| 2026-09-21 12:00 |
23:01:28.92 |
-05:02:59.6 |
HIP 113686 |
20.32 |
| 2026-09-22 00:00 |
23:01:25.83 |
-05:03:19.3 |
HIP 113686 |
20.68 |
| 2026-09-22 12:00 |
23:01:22.75 |
-05:03:39.0 |
HIP 113686 |
21.08 |
| 2026-09-23 00:00 |
23:01:19.68 |
-05:03:58.7 |
HIP 113686 |
21.50 |
| 2026-09-23 12:00 |
23:01:16.62 |
-05:04:18.3 |
HIP 113686 |
21.94 |
| 2026-09-24 00:00 |
23:01:13.56 |
-05:04:37.8 |
HIP 113686 |
22.40 |
| 2026-09-24 12:00 |
23:01:10.51 |
-05:04:57.4 |
HIP 113686 |
22.88 |
| 2026-09-25 00:00 |
23:01:07.47 |
-05:05:16.9 |
HIP 113686 |
23.38 |
| 2026-09-25 12:00 |
23:01:04.44 |
-05:05:36.3 |
HIP 113686 |
23.90 |
| 2026-09-26 00:00 |
23:01:01.42 |
-05:05:55.7 |
HIP 113686 |
24.43 |
| 2026-09-26 12:00 |
23:00:58.41 |
-05:06:15.0 |
HIP 113686 |
24.98 |
| 2026-09-27 00:00 |
23:00:55.40 |
-05:06:34.3 |
HIP 113686 |
25.54 |
| 2026-09-27 12:00 |
23:00:52.41 |
-05:06:53.5 |
HIP 113686 |
26.11 |
| 2026-09-28 00:00 |
23:00:49.42 |
-05:07:12.7 |
HIP 113686 |
26.69 |
| 2026-09-28 12:00 |
23:00:46.45 |
-05:07:31.9 |
HIP 113686 |
27.28 |
| 2026-09-29 00:00 |
23:00:43.48 |
-05:07:50.9 |
HIP 113686 |
27.88 |
| 2026-09-29 12:00 |
23:00:40.53 |
-05:08:09.9 |
HIP 113686 |
28.49 |
| 2026-09-30 00:00 |
23:00:37.59 |
-05:08:28.9 |
HIP 113686 |
29.10 |
| 2026-09-30 12:00 |
23:00:34.65 |
-05:08:47.8 |
HIP 113686 |
29.72 |
| 2026-10-01 00:00 |
23:00:31.73 |
-05:09:06.6 |
HIP 113686 |
30.35 |
| 2026-10-01 12:00 |
23:00:28.82 |
-05:09:25.4 |
HIP 113686 |
30.98 |
| 2026-10-02 00:00 |
23:00:25.92 |
-05:09:44.1 |
HIP 113686 |
31.62 |
| 2026-10-02 12:00 |
23:00:23.03 |
-05:10:02.8 |
HIP 113686 |
32.26 |
| 2026-10-03 00:00 |
23:00:20.16 |
-05:10:21.3 |
HIP 113686 |
32.91 |
| 2026-10-03 12:00 |
23:00:17.30 |
-05:10:39.8 |
HIP 113686 |
33.56 |
| 2026-10-04 00:00 |
23:00:14.44 |
-05:10:58.3 |
HIP 113686 |
34.21 |
| 2026-10-04 12:00 |
23:00:11.61 |
-05:11:16.6 |
HIP 113686 |
34.86 |
| 2026-10-05 00:00 |
23:00:08.78 |
-05:11:34.9 |
HIP 113686 |
35.52 |
| 2026-10-05 12:00 |
23:00:05.97 |
-05:11:53.2 |
HIP 113686 |
36.17 |
| 2026-10-06 00:00 |
23:00:03.17 |
-05:12:11.3 |
HIP 113451 |
35.67 |
| 2026-10-06 12:00 |
23:00:00.38 |
-05:12:29.4 |
HIP 113451 |
35.01 |
| 2026-10-07 00:00 |
22:59:57.61 |
-05:12:47.4 |
HIP 113451 |
34.36 |
| 2026-10-07 12:00 |
22:59:54.85 |
-05:13:05.3 |
HIP 113451 |
33.71 |
| 2026-10-08 00:00 |
22:59:52.11 |
-05:13:23.1 |
HIP 113451 |
33.08 |
| 2026-10-08 12:00 |
22:59:49.38 |
-05:13:40.8 |
HIP 113451 |
32.45 |
| 2026-10-09 00:00 |
22:59:46.66 |
-05:13:58.5 |
HIP 113451 |
31.82 |
| 2026-10-09 12:00 |
22:59:43.96 |
-05:14:16.1 |
HIP 113451 |
31.21 |
| 2026-10-10 00:00 |
22:59:41.27 |
-05:14:33.6 |
HIP 113451 |
30.60 |
| 2026-10-10 12:00 |
22:59:38.60 |
-05:14:51.0 |
HIP 113451 |
30.00 |
| 2026-10-11 00:00 |
22:59:35.95 |
-05:15:08.3 |
HIP 113451 |
29.42 |