| Parameter |
Value |
| Designation |
C/2008 P1 (Garradd) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2009-07-22T22:51:56.433600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:21Z |
| Obs used |
1345 |
| NEO |
- |
| M1 |
11.100 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-08-25.0000000 |
| e |
1.00167859 |
| q (au) |
3.896111 |
| a (au) |
-2321.061664 |
| i (deg) |
64.310315 |
| Ω (om, deg) |
357.676994 |
| ω (w, deg) |
11.865464 |
| M (ma, deg) |
0.000291 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.382 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.382 |
| n |
2.000 |
| gf |
0.960 |
| gb |
-0.747 |
| k |
1.000 |
| δ90 |
9.885 |
| 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 |
| 2008-08-13 |
2009-07-21 |
-8.6915 |
+4.482 |
| 2009-07-23 |
2011-02-04 |
+5.2294 |
-3.081 |
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 |
11:39:40.90 |
+29:42:11.5 |
HIP 56794 |
14.32 |
| 2026-06-01 12:00 |
11:39:40.02 |
+29:41:48.2 |
HIP 56794 |
14.23 |
| 2026-06-02 00:00 |
11:39:39.17 |
+29:41:24.7 |
HIP 56794 |
14.15 |
| 2026-06-02 12:00 |
11:39:38.35 |
+29:41:00.9 |
HIP 56794 |
14.10 |
| 2026-06-03 00:00 |
11:39:37.56 |
+29:40:37.0 |
HIP 56794 |
14.07 |
| 2026-06-03 12:00 |
11:39:36.80 |
+29:40:13.0 |
HIP 56794 |
14.06 |
| 2026-06-04 00:00 |
11:39:36.08 |
+29:39:48.7 |
HIP 56794 |
14.07 |
| 2026-06-04 12:00 |
11:39:35.38 |
+29:39:24.3 |
HIP 56794 |
14.09 |
| 2026-06-05 00:00 |
11:39:34.71 |
+29:38:59.7 |
HIP 56794 |
14.15 |
| 2026-06-05 12:00 |
11:39:34.08 |
+29:38:34.9 |
HIP 56794 |
14.22 |
| 2026-06-06 00:00 |
11:39:33.48 |
+29:38:09.9 |
HIP 56794 |
14.31 |
| 2026-06-06 12:00 |
11:39:32.90 |
+29:37:44.8 |
HIP 56794 |
14.42 |
| 2026-06-07 00:00 |
11:39:32.36 |
+29:37:19.4 |
HIP 56794 |
14.55 |
| 2026-06-07 12:00 |
11:39:31.85 |
+29:36:54.0 |
HIP 56794 |
14.70 |
| 2026-06-08 00:00 |
11:39:31.37 |
+29:36:28.3 |
HIP 56794 |
14.87 |
| 2026-06-08 12:00 |
11:39:30.93 |
+29:36:02.5 |
HIP 56794 |
15.05 |
| 2026-06-09 00:00 |
11:39:30.51 |
+29:35:36.5 |
HIP 56794 |
15.25 |
| 2026-06-09 12:00 |
11:39:30.12 |
+29:35:10.4 |
HIP 56794 |
15.48 |
| 2026-06-10 00:00 |
11:39:29.77 |
+29:34:44.1 |
HIP 56794 |
15.71 |
| 2026-06-10 12:00 |
11:39:29.45 |
+29:34:17.6 |
HIP 56794 |
15.96 |
| 2026-06-11 00:00 |
11:39:29.15 |
+29:33:51.0 |
HIP 56794 |
16.23 |
| 2026-06-11 12:00 |
11:39:28.89 |
+29:33:24.2 |
HIP 56794 |
16.51 |
| 2026-06-12 00:00 |
11:39:28.66 |
+29:32:57.3 |
HIP 56794 |
16.81 |
| 2026-06-12 12:00 |
11:39:28.47 |
+29:32:30.2 |
HIP 56794 |
17.12 |
| 2026-06-13 00:00 |
11:39:28.30 |
+29:32:02.9 |
HIP 56794 |
17.44 |
| 2026-06-13 12:00 |
11:39:28.16 |
+29:31:35.5 |
HIP 56794 |
17.77 |
| 2026-06-14 00:00 |
11:39:28.06 |
+29:31:08.0 |
HIP 56794 |
18.12 |
| 2026-06-14 12:00 |
11:39:27.98 |
+29:30:40.3 |
HIP 56794 |
18.47 |
| 2026-06-15 00:00 |
11:39:27.94 |
+29:30:12.4 |
HIP 56794 |
18.84 |
| 2026-06-15 12:00 |
11:39:27.93 |
+29:29:44.5 |
HIP 56794 |
19.21 |
| 2026-06-16 00:00 |
11:39:27.95 |
+29:29:16.3 |
HIP 56794 |
19.60 |
| 2026-06-16 12:00 |
11:39:28.00 |
+29:28:48.1 |
HIP 56794 |
20.00 |
| 2026-06-17 00:00 |
11:39:28.08 |
+29:28:19.7 |
HIP 56794 |
20.40 |
| 2026-06-17 12:00 |
11:39:28.19 |
+29:27:51.2 |
HIP 56794 |
20.81 |
| 2026-06-18 00:00 |
11:39:28.33 |
+29:27:22.5 |
HIP 56794 |
21.23 |
| 2026-06-18 12:00 |
11:39:28.51 |
+29:26:53.7 |
HIP 56794 |
21.66 |
| 2026-06-19 00:00 |
11:39:28.71 |
+29:26:24.8 |
HIP 56914 |
21.99 |
| 2026-06-19 12:00 |
11:39:28.95 |
+29:25:55.7 |
HIP 56914 |
21.52 |
| 2026-06-20 00:00 |
11:39:29.21 |
+29:25:26.5 |
HIP 56914 |
21.05 |
| 2026-06-20 12:00 |
11:39:29.51 |
+29:24:57.2 |
HIP 56914 |
20.57 |
| 2026-06-21 00:00 |
11:39:29.84 |
+29:24:27.8 |
HIP 56914 |
20.09 |
| 2026-06-21 12:00 |
11:39:30.19 |
+29:23:58.3 |
HIP 56914 |
19.60 |
| 2026-06-22 00:00 |
11:39:30.58 |
+29:23:28.6 |
HIP 56914 |
19.12 |