C/2007 E1 (Garradd)
| 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) |
| 2026-02-03 00:00 |
23:00:56.51 |
-05:08:10.2 |
HIP 113686 |
26.95 |
| 2026-02-03 12:00 |
23:00:59.01 |
-05:07:55.4 |
HIP 113686 |
26.52 |
| 2026-02-04 00:00 |
23:01:01.52 |
-05:07:40.5 |
HIP 113686 |
26.09 |
| 2026-02-04 12:00 |
23:01:04.04 |
-05:07:25.5 |
HIP 113686 |
25.68 |
| 2026-02-05 00:00 |
23:01:06.58 |
-05:07:10.4 |
HIP 113686 |
25.27 |
| 2026-02-05 12:00 |
23:01:09.12 |
-05:06:55.3 |
HIP 113686 |
24.88 |
| 2026-02-06 00:00 |
23:01:11.68 |
-05:06:40.1 |
HIP 113686 |
24.49 |
| 2026-02-06 12:00 |
23:01:14.25 |
-05:06:24.8 |
HIP 113686 |
24.12 |
| 2026-02-07 00:00 |
23:01:16.83 |
-05:06:09.4 |
HIP 113686 |
23.76 |
| 2026-02-07 12:00 |
23:01:19.42 |
-05:05:53.9 |
HIP 113686 |
23.41 |
| 2026-02-08 00:00 |
23:01:22.02 |
-05:05:38.4 |
HIP 113686 |
23.08 |
| 2026-02-08 12:00 |
23:01:24.63 |
-05:05:22.8 |
HIP 113686 |
22.76 |
| 2026-02-09 00:00 |
23:01:27.26 |
-05:05:07.1 |
HIP 113686 |
22.46 |
| 2026-02-09 12:00 |
23:01:29.89 |
-05:04:51.3 |
HIP 113686 |
22.17 |
| 2026-02-10 00:00 |
23:01:32.53 |
-05:04:35.5 |
HIP 113686 |
21.90 |
| 2026-02-10 12:00 |
23:01:35.18 |
-05:04:19.6 |
HIP 113686 |
21.66 |
| 2026-02-11 00:00 |
23:01:37.84 |
-05:04:03.7 |
HIP 113686 |
21.43 |
| 2026-02-11 12:00 |
23:01:40.52 |
-05:03:47.6 |
HIP 113686 |
21.22 |
| 2026-02-12 00:00 |
23:01:43.20 |
-05:03:31.5 |
HIP 113686 |
21.03 |
| 2026-02-12 12:00 |
23:01:45.89 |
-05:03:15.4 |
HIP 113686 |
20.87 |
| 2026-02-13 00:00 |
23:01:48.58 |
-05:02:59.1 |
HIP 113686 |
20.73 |
| 2026-02-13 12:00 |
23:01:51.29 |
-05:02:42.8 |
HIP 113686 |
20.61 |
| 2026-02-14 00:00 |
23:01:54.00 |
-05:02:26.5 |
HIP 113686 |
20.52 |
| 2026-02-14 12:00 |
23:01:56.73 |
-05:02:10.1 |
HIP 113686 |
20.45 |
| 2026-02-15 00:00 |
23:01:59.46 |
-05:01:53.6 |
HIP 113686 |
20.41 |
| 2026-02-15 12:00 |
23:02:02.19 |
-05:01:37.1 |
HIP 113686 |
20.40 |
| 2026-02-16 00:00 |
23:02:04.94 |
-05:01:20.5 |
HIP 113686 |
20.41 |
| 2026-02-16 12:00 |
23:02:07.69 |
-05:01:03.9 |
HIP 113686 |
20.45 |
| 2026-02-17 00:00 |
23:02:10.45 |
-05:00:47.2 |
HIP 113686 |
20.51 |
| 2026-02-17 12:00 |
23:02:13.22 |
-05:00:30.4 |
HIP 113686 |
20.60 |
| 2026-02-18 00:00 |
23:02:15.99 |
-05:00:13.7 |
HIP 113686 |
20.72 |
| 2026-02-18 12:00 |
23:02:18.77 |
-04:59:56.8 |
HIP 113686 |
20.86 |
| 2026-02-19 00:00 |
23:02:21.56 |
-04:59:39.9 |
HIP 113686 |
21.03 |
| 2026-02-19 12:00 |
23:02:24.35 |
-04:59:23.0 |
HIP 113686 |
21.23 |
| 2026-02-20 00:00 |
23:02:27.15 |
-04:59:06.0 |
HIP 113686 |
21.45 |
| 2026-02-20 12:00 |
23:02:29.95 |
-04:58:49.0 |
HIP 113686 |
21.69 |
| 2026-02-21 00:00 |
23:02:32.75 |
-04:58:31.9 |
HIP 113686 |
21.96 |
| 2026-02-21 12:00 |
23:02:35.57 |
-04:58:14.8 |
HIP 113686 |
22.25 |
| 2026-02-22 00:00 |
23:02:38.38 |
-04:57:57.7 |
HIP 113896 |
22.13 |
| 2026-02-22 12:00 |
23:02:41.21 |
-04:57:40.5 |
HIP 113896 |
21.37 |
| 2026-02-23 00:00 |
23:02:44.03 |
-04:57:23.3 |
HIP 113896 |
20.62 |
| 2026-02-23 12:00 |
23:02:46.86 |
-04:57:06.0 |
HIP 113896 |
19.86 |
| 2026-02-24 00:00 |
23:02:49.70 |
-04:56:48.8 |
HIP 113896 |
19.10 |