| Parameter |
Value |
| Designation |
C/2009 P1 (Garradd) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-12-23T16:15:40.786560Z |
| Orbit solution date (soln_date, UTC) |
2026-03-07T14:42:53Z |
| Obs used |
9048 |
| NEO |
- |
| M1 |
8.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-11-22.0000000 |
| e |
1.00099744 |
| q (au) |
1.550536 |
| a (au) |
-1554.522037 |
| i (deg) |
106.177292 |
| Ω (om, deg) |
325.997229 |
| ω (w, deg) |
90.747065 |
| M (ma, deg) |
-0.000509 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.187 + 2.504\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.187 |
| n |
2.504 |
| gf |
1.000 |
| gb |
-0.551 |
| 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 |
| 2008-09-27 |
2011-06-07 |
+2.1128 |
-2.842 |
| 2011-06-07 |
2011-12-23 |
-2.4195 |
-0.163 |
| 2011-12-24 |
2012-06-08 |
-0.1267 |
-0.782 |
| 2012-06-08 |
2014-02-26 |
+9.1201 |
-5.087 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
06:55:55.16 |
-37:09:50.4 |
HIP 33213 |
18.94 |
| 2026-06-01 12:00 |
06:55:58.78 |
-37:09:29.4 |
HIP 33213 |
19.71 |
| 2026-06-02 00:00 |
06:56:02.42 |
-37:09:08.7 |
HIP 33213 |
20.49 |
| 2026-06-02 12:00 |
06:56:06.08 |
-37:08:48.4 |
HIP 33442 |
20.43 |
| 2026-06-03 00:00 |
06:56:09.76 |
-37:08:28.4 |
HIP 33442 |
19.70 |
| 2026-06-03 12:00 |
06:56:13.46 |
-37:08:08.8 |
HIP 33442 |
18.99 |
| 2026-06-04 00:00 |
06:56:17.17 |
-37:07:49.5 |
HIP 33442 |
18.28 |
| 2026-06-04 12:00 |
06:56:20.90 |
-37:07:30.6 |
HIP 33442 |
17.59 |
| 2026-06-05 00:00 |
06:56:24.65 |
-37:07:12.0 |
HIP 33442 |
16.90 |
| 2026-06-05 12:00 |
06:56:28.42 |
-37:06:53.8 |
HIP 33442 |
16.24 |
| 2026-06-06 00:00 |
06:56:32.20 |
-37:06:35.9 |
HIP 33442 |
15.59 |
| 2026-06-06 12:00 |
06:56:36.00 |
-37:06:18.4 |
HIP 33442 |
14.96 |
| 2026-06-07 00:00 |
06:56:39.81 |
-37:06:01.2 |
HIP 33442 |
14.35 |
| 2026-06-07 12:00 |
06:56:43.64 |
-37:05:44.5 |
HIP 33442 |
13.77 |
| 2026-06-08 00:00 |
06:56:47.49 |
-37:05:28.0 |
HIP 33442 |
13.21 |
| 2026-06-08 12:00 |
06:56:51.35 |
-37:05:12.0 |
HIP 33442 |
12.69 |
| 2026-06-09 00:00 |
06:56:55.23 |
-37:04:56.3 |
HIP 33442 |
12.21 |
| 2026-06-09 12:00 |
06:56:59.12 |
-37:04:40.9 |
HIP 33442 |
11.77 |
| 2026-06-10 00:00 |
06:57:03.03 |
-37:04:25.9 |
HIP 33442 |
11.37 |
| 2026-06-10 12:00 |
06:57:06.95 |
-37:04:11.3 |
HIP 33442 |
11.03 |
| 2026-06-11 00:00 |
06:57:10.88 |
-37:03:57.1 |
HIP 33442 |
10.75 |
| 2026-06-11 12:00 |
06:57:14.83 |
-37:03:43.2 |
HIP 33442 |
10.53 |
| 2026-06-12 00:00 |
06:57:18.80 |
-37:03:29.7 |
HIP 33442 |
10.37 |
| 2026-06-12 12:00 |
06:57:22.77 |
-37:03:16.6 |
HIP 33442 |
10.29 |
| 2026-06-13 00:00 |
06:57:26.76 |
-37:03:03.8 |
HIP 33442 |
10.28 |
| 2026-06-13 12:00 |
06:57:30.76 |
-37:02:51.4 |
HIP 33442 |
10.34 |
| 2026-06-14 00:00 |
06:57:34.78 |
-37:02:39.4 |
HIP 33442 |
10.47 |
| 2026-06-14 12:00 |
06:57:38.80 |
-37:02:27.8 |
HIP 33442 |
10.67 |
| 2026-06-15 00:00 |
06:57:42.84 |
-37:02:16.5 |
HIP 33442 |
10.94 |
| 2026-06-15 12:00 |
06:57:46.89 |
-37:02:05.6 |
HIP 33442 |
11.27 |
| 2026-06-16 00:00 |
06:57:50.95 |
-37:01:55.1 |
HIP 33442 |
11.66 |
| 2026-06-16 12:00 |
06:57:55.02 |
-37:01:45.0 |
HIP 33442 |
12.09 |
| 2026-06-17 00:00 |
06:57:59.11 |
-37:01:35.3 |
HIP 33442 |
12.58 |
| 2026-06-17 12:00 |
06:58:03.20 |
-37:01:25.9 |
HIP 33442 |
13.10 |
| 2026-06-18 00:00 |
06:58:07.30 |
-37:01:16.9 |
HIP 33442 |
13.66 |
| 2026-06-18 12:00 |
06:58:11.41 |
-37:01:08.3 |
HIP 33442 |
14.25 |
| 2026-06-19 00:00 |
06:58:15.54 |
-37:01:00.1 |
HIP 33442 |
14.87 |
| 2026-06-19 12:00 |
06:58:19.67 |
-37:00:52.2 |
HIP 33442 |
15.51 |
| 2026-06-20 00:00 |
06:58:23.81 |
-37:00:44.7 |
HIP 33629 |
15.16 |
| 2026-06-20 12:00 |
06:58:27.96 |
-37:00:37.6 |
HIP 33629 |
14.56 |
| 2026-06-21 00:00 |
06:58:32.11 |
-37:00:30.9 |
HIP 33629 |
13.99 |
| 2026-06-21 12:00 |
06:58:36.28 |
-37:00:24.6 |
HIP 33629 |
13.45 |
| 2026-06-22 00:00 |
06:58:40.45 |
-37:00:18.7 |
HIP 33629 |
12.95 |