| 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) |
| 2026-07-29 00:00 |
07:03:50.98 |
-37:10:30.4 |
HIP 34011 |
5.12 |
| 2026-07-29 12:00 |
07:03:54.93 |
-37:10:52.5 |
HIP 34011 |
5.76 |
| 2026-07-30 00:00 |
07:03:58.87 |
-37:11:14.9 |
HIP 34011 |
6.45 |
| 2026-07-30 12:00 |
07:04:02.80 |
-37:11:37.6 |
HIP 34011 |
7.17 |
| 2026-07-31 00:00 |
07:04:06.72 |
-37:12:00.7 |
HIP 34011 |
7.92 |
| 2026-07-31 12:00 |
07:04:10.62 |
-37:12:24.2 |
HIP 34011 |
8.70 |
| 2026-08-01 00:00 |
07:04:14.50 |
-37:12:47.9 |
HIP 34011 |
9.48 |
| 2026-08-01 12:00 |
07:04:18.37 |
-37:13:12.0 |
HIP 34011 |
10.28 |
| 2026-08-02 00:00 |
07:04:22.23 |
-37:13:36.5 |
HIP 34011 |
11.08 |
| 2026-08-02 12:00 |
07:04:26.07 |
-37:14:01.3 |
HIP 34011 |
11.89 |
| 2026-08-03 00:00 |
07:04:29.90 |
-37:14:26.4 |
HIP 34090 |
11.99 |
| 2026-08-03 12:00 |
07:04:33.71 |
-37:14:51.9 |
HIP 34090 |
11.91 |
| 2026-08-04 00:00 |
07:04:37.50 |
-37:15:17.7 |
HIP 34090 |
11.88 |
| 2026-08-04 12:00 |
07:04:41.28 |
-37:15:43.8 |
HIP 34090 |
11.91 |
| 2026-08-05 00:00 |
07:04:45.04 |
-37:16:10.2 |
HIP 34090 |
12.00 |
| 2026-08-05 12:00 |
07:04:48.79 |
-37:16:37.0 |
HIP 34090 |
12.14 |
| 2026-08-06 00:00 |
07:04:52.52 |
-37:17:04.1 |
HIP 34090 |
12.34 |
| 2026-08-06 12:00 |
07:04:56.23 |
-37:17:31.6 |
HIP 34090 |
12.58 |
| 2026-08-07 00:00 |
07:04:59.92 |
-37:17:59.3 |
HIP 34090 |
12.88 |
| 2026-08-07 12:00 |
07:05:03.60 |
-37:18:27.4 |
HIP 34090 |
13.21 |
| 2026-08-08 00:00 |
07:05:07.26 |
-37:18:55.8 |
HIP 34090 |
13.59 |
| 2026-08-08 12:00 |
07:05:10.90 |
-37:19:24.6 |
HIP 34090 |
14.01 |
| 2026-08-09 00:00 |
07:05:14.52 |
-37:19:53.6 |
HIP 34090 |
14.46 |
| 2026-08-09 12:00 |
07:05:18.12 |
-37:20:23.0 |
HIP 34090 |
14.94 |
| 2026-08-10 00:00 |
07:05:21.70 |
-37:20:52.7 |
HIP 34090 |
15.46 |
| 2026-08-10 12:00 |
07:05:25.27 |
-37:21:22.7 |
HIP 34090 |
15.99 |
| 2026-08-11 00:00 |
07:05:28.81 |
-37:21:53.0 |
HIP 34216 |
16.03 |
| 2026-08-11 12:00 |
07:05:32.34 |
-37:22:23.7 |
HIP 34216 |
15.45 |
| 2026-08-12 00:00 |
07:05:35.84 |
-37:22:54.6 |
HIP 34216 |
14.88 |
| 2026-08-12 12:00 |
07:05:39.33 |
-37:23:25.9 |
HIP 34216 |
14.34 |
| 2026-08-13 00:00 |
07:05:42.79 |
-37:23:57.4 |
HIP 34216 |
13.83 |
| 2026-08-13 12:00 |
07:05:46.23 |
-37:24:29.3 |
HIP 34216 |
13.35 |
| 2026-08-14 00:00 |
07:05:49.65 |
-37:25:01.4 |
HIP 34216 |
12.90 |
| 2026-08-14 12:00 |
07:05:53.05 |
-37:25:33.9 |
HIP 34216 |
12.49 |
| 2026-08-15 00:00 |
07:05:56.43 |
-37:26:06.7 |
HIP 34216 |
12.12 |
| 2026-08-15 12:00 |
07:05:59.78 |
-37:26:39.7 |
HIP 34216 |
11.80 |
| 2026-08-16 00:00 |
07:06:03.12 |
-37:27:13.1 |
HIP 34216 |
11.53 |
| 2026-08-16 12:00 |
07:06:06.43 |
-37:27:46.7 |
HIP 34216 |
11.31 |
| 2026-08-17 00:00 |
07:06:09.71 |
-37:28:20.7 |
HIP 34216 |
11.15 |
| 2026-08-17 12:00 |
07:06:12.98 |
-37:28:54.9 |
HIP 34216 |
11.04 |
| 2026-08-18 00:00 |
07:06:16.22 |
-37:29:29.4 |
HIP 34216 |
11.00 |
| 2026-08-18 12:00 |
07:06:19.43 |
-37:30:04.2 |
HIP 34216 |
11.02 |
| 2026-08-19 00:00 |
07:06:22.63 |
-37:30:39.3 |
HIP 34216 |
11.09 |