| Parameter |
Value |
| Designation |
C/2009 U1 (Garradd) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-10-07T22:02:42.892800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:36Z |
| Obs used |
10 |
| NEO |
- |
| M1 |
7.800 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-10-19.0000000 |
| e |
1.01500924 |
| q (au) |
5.382605 |
| a (au) |
-358.619493 |
| i (deg) |
91.236070 |
| Ω (om, deg) |
43.385462 |
| ω (w, deg) |
269.043011 |
| M (ma, deg) |
0.054580 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.039 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.039 |
| n |
6.000 |
| gf |
0.976 |
| gb |
-0.942 |
| k |
0.801 |
| δ90 |
5.609 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
01:24:48.28 |
+52:52:22.2 |
HIP 6496 |
13.05 |
| 2026-05-12 12:00 |
01:24:52.61 |
+52:52:55.0 |
HIP 6496 |
13.84 |
| 2026-05-13 00:00 |
01:24:56.92 |
+52:53:28.0 |
HIP 6496 |
14.64 |
| 2026-05-13 12:00 |
01:25:01.21 |
+52:54:01.2 |
HIP 6496 |
15.44 |
| 2026-05-14 00:00 |
01:25:05.48 |
+52:54:34.6 |
HIP 6496 |
16.24 |
| 2026-05-14 12:00 |
01:25:09.73 |
+52:55:08.2 |
HIP 6583 |
16.95 |
| 2026-05-15 00:00 |
01:25:13.96 |
+52:55:42.0 |
HIP 6583 |
16.65 |
| 2026-05-15 12:00 |
01:25:18.17 |
+52:56:16.0 |
HIP 6725 |
16.04 |
| 2026-05-16 00:00 |
01:25:22.35 |
+52:56:50.2 |
HIP 6725 |
15.20 |
| 2026-05-16 12:00 |
01:25:26.52 |
+52:57:24.5 |
HIP 6725 |
14.35 |
| 2026-05-17 00:00 |
01:25:30.66 |
+52:57:59.0 |
HIP 6725 |
13.50 |
| 2026-05-17 12:00 |
01:25:34.78 |
+52:58:33.7 |
HIP 6725 |
12.65 |
| 2026-05-18 00:00 |
01:25:38.88 |
+52:59:08.6 |
HIP 6725 |
11.81 |
| 2026-05-18 12:00 |
01:25:42.95 |
+52:59:43.7 |
HIP 6725 |
10.96 |
| 2026-05-19 00:00 |
01:25:47.00 |
+53:00:18.9 |
HIP 6725 |
10.12 |
| 2026-05-19 12:00 |
01:25:51.03 |
+53:00:54.4 |
HIP 6725 |
9.28 |
| 2026-05-20 00:00 |
01:25:55.04 |
+53:01:29.9 |
HIP 6725 |
8.43 |
| 2026-05-20 12:00 |
01:25:59.01 |
+53:02:05.7 |
HIP 6725 |
7.59 |
| 2026-05-21 00:00 |
01:26:02.97 |
+53:02:41.6 |
HIP 6725 |
6.75 |
| 2026-05-21 12:00 |
01:26:06.90 |
+53:03:17.7 |
HIP 6725 |
5.91 |
| 2026-05-22 00:00 |
01:26:10.80 |
+53:03:53.9 |
HIP 6725 |
5.07 |
| 2026-05-22 12:00 |
01:26:14.68 |
+53:04:30.4 |
HIP 6725 |
4.23 |
| 2026-05-23 00:00 |
01:26:18.54 |
+53:05:06.9 |
HIP 6725 |
3.39 |
| 2026-05-23 12:00 |
01:26:22.37 |
+53:05:43.6 |
HIP 6725 |
2.56 |
| 2026-05-24 00:00 |
01:26:26.17 |
+53:06:20.5 |
HIP 6725 |
1.73 |
| 2026-05-24 12:00 |
01:26:29.94 |
+53:06:57.5 |
HIP 6725 |
0.92 |
| 2026-05-25 00:00 |
01:26:33.69 |
+53:07:34.7 |
HIP 6725 |
0.31 |
| 2026-05-25 12:00 |
01:26:37.42 |
+53:08:12.0 |
HIP 6725 |
0.86 |
| 2026-05-26 00:00 |
01:26:41.11 |
+53:08:49.5 |
HIP 6725 |
1.67 |
| 2026-05-26 12:00 |
01:26:44.78 |
+53:09:27.1 |
HIP 6725 |
2.49 |
| 2026-05-27 00:00 |
01:26:48.42 |
+53:10:04.8 |
HIP 6725 |
3.32 |
| 2026-05-27 12:00 |
01:26:52.03 |
+53:10:42.7 |
HIP 6725 |
4.15 |
| 2026-05-28 00:00 |
01:26:55.61 |
+53:11:20.7 |
HIP 6725 |
4.97 |
| 2026-05-28 12:00 |
01:26:59.17 |
+53:11:58.9 |
HIP 6725 |
5.80 |
| 2026-05-29 00:00 |
01:27:02.70 |
+53:12:37.2 |
HIP 6725 |
6.63 |
| 2026-05-29 12:00 |
01:27:06.20 |
+53:13:15.6 |
HIP 6725 |
7.45 |
| 2026-05-30 00:00 |
01:27:09.67 |
+53:13:54.1 |
HIP 6725 |
8.28 |
| 2026-05-30 12:00 |
01:27:13.11 |
+53:14:32.8 |
HIP 6725 |
9.10 |
| 2026-05-31 00:00 |
01:27:16.52 |
+53:15:11.6 |
HIP 6725 |
9.92 |
| 2026-05-31 12:00 |
01:27:19.90 |
+53:15:50.5 |
HIP 6725 |
10.74 |
| 2026-06-01 00:00 |
01:27:23.25 |
+53:16:29.6 |
HIP 6725 |
11.56 |
| 2026-06-01 12:00 |
01:27:26.57 |
+53:17:08.7 |
HIP 6725 |
12.38 |
| 2026-06-02 00:00 |
01:27:29.86 |
+53:17:48.0 |
HIP 6725 |
13.20 |