| Parameter |
Value |
| Designation |
C/2008 C1 (Chen-Gao) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-04-16T20:25:39.135360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:16Z |
| Obs used |
754 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
5.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-03-06.0000000 |
| e |
1.00000066 |
| q (au) |
1.262346 |
| a (au) |
-1909647.271764 |
| i (deg) |
61.784520 |
| Ω (om, deg) |
307.782377 |
| ω (w, deg) |
180.928392 |
| M (ma, deg) |
-0.000000 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.986 + 2.066\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.986 |
| n |
2.066 |
| gf |
0.999 |
| gb |
-0.998 |
| 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 |
| 2008-01-30 |
2008-04-16 |
+12.3117 |
-3.108 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
20:24:02.74 |
-37:23:18.9 |
HIP 100584 |
7.12 |
| 2026-03-26 12:00 |
20:24:04.65 |
-37:23:24.7 |
HIP 100584 |
7.17 |
| 2026-03-27 00:00 |
20:24:06.54 |
-37:23:30.6 |
HIP 100584 |
7.24 |
| 2026-03-27 12:00 |
20:24:08.40 |
-37:23:36.7 |
HIP 100584 |
7.32 |
| 2026-03-28 00:00 |
20:24:10.23 |
-37:23:42.9 |
HIP 100584 |
7.41 |
| 2026-03-28 12:00 |
20:24:12.03 |
-37:23:49.2 |
HIP 100584 |
7.52 |
| 2026-03-29 00:00 |
20:24:13.80 |
-37:23:55.7 |
HIP 100584 |
7.64 |
| 2026-03-29 12:00 |
20:24:15.54 |
-37:24:02.3 |
HIP 100584 |
7.77 |
| 2026-03-30 00:00 |
20:24:17.25 |
-37:24:09.0 |
HIP 100584 |
7.91 |
| 2026-03-30 12:00 |
20:24:18.93 |
-37:24:15.9 |
HIP 100584 |
8.05 |
| 2026-03-31 00:00 |
20:24:20.58 |
-37:24:22.9 |
HIP 100584 |
8.20 |
| 2026-03-31 12:00 |
20:24:22.21 |
-37:24:30.0 |
HIP 100584 |
8.36 |
| 2026-04-01 00:00 |
20:24:23.80 |
-37:24:37.3 |
HIP 100584 |
8.53 |
| 2026-04-01 12:00 |
20:24:25.36 |
-37:24:44.7 |
HIP 100584 |
8.69 |
| 2026-04-02 00:00 |
20:24:26.90 |
-37:24:52.2 |
HIP 100584 |
8.86 |
| 2026-04-02 12:00 |
20:24:28.40 |
-37:25:00.0 |
HIP 100584 |
9.04 |
| 2026-04-03 00:00 |
20:24:29.87 |
-37:25:07.7 |
HIP 100584 |
9.21 |
| 2026-04-03 12:00 |
20:24:31.32 |
-37:25:15.7 |
HIP 100584 |
9.39 |
| 2026-04-04 00:00 |
20:24:32.73 |
-37:25:23.7 |
HIP 100584 |
9.56 |
| 2026-04-04 12:00 |
20:24:34.11 |
-37:25:31.9 |
HIP 100584 |
9.74 |
| 2026-04-05 00:00 |
20:24:35.46 |
-37:25:40.2 |
HIP 100584 |
9.92 |
| 2026-04-05 12:00 |
20:24:36.78 |
-37:25:48.7 |
HIP 100584 |
10.10 |
| 2026-04-06 00:00 |
20:24:38.07 |
-37:25:57.3 |
HIP 100584 |
10.27 |
| 2026-04-06 12:00 |
20:24:39.33 |
-37:26:06.0 |
HIP 100584 |
10.45 |
| 2026-04-07 00:00 |
20:24:40.56 |
-37:26:14.8 |
HIP 100584 |
10.62 |
| 2026-04-07 12:00 |
20:24:41.75 |
-37:26:23.8 |
HIP 100584 |
10.79 |
| 2026-04-08 00:00 |
20:24:42.92 |
-37:26:32.8 |
HIP 100584 |
10.96 |
| 2026-04-08 12:00 |
20:24:44.05 |
-37:26:42.0 |
HIP 100584 |
11.13 |
| 2026-04-09 00:00 |
20:24:45.16 |
-37:26:51.4 |
HIP 100584 |
11.29 |
| 2026-04-09 12:00 |
20:24:46.23 |
-37:27:00.8 |
HIP 100584 |
11.45 |
| 2026-04-10 00:00 |
20:24:47.27 |
-37:27:10.4 |
HIP 100584 |
11.61 |
| 2026-04-10 12:00 |
20:24:48.28 |
-37:27:20.1 |
HIP 100584 |
11.77 |
| 2026-04-11 00:00 |
20:24:49.25 |
-37:27:29.9 |
HIP 100584 |
11.92 |
| 2026-04-11 12:00 |
20:24:50.20 |
-37:27:39.9 |
HIP 100584 |
12.07 |
| 2026-04-12 00:00 |
20:24:51.11 |
-37:27:49.9 |
HIP 100584 |
12.22 |
| 2026-04-12 12:00 |
20:24:51.99 |
-37:28:00.1 |
HIP 100584 |
12.36 |
| 2026-04-13 00:00 |
20:24:52.84 |
-37:28:10.4 |
HIP 100584 |
12.50 |
| 2026-04-13 12:00 |
20:24:53.65 |
-37:28:20.8 |
HIP 100584 |
12.63 |
| 2026-04-14 00:00 |
20:24:54.43 |
-37:28:31.3 |
HIP 100584 |
12.77 |
| 2026-04-14 12:00 |
20:24:55.19 |
-37:28:42.0 |
HIP 100584 |
12.89 |
| 2026-04-15 00:00 |
20:24:55.90 |
-37:28:52.7 |
HIP 100584 |
13.02 |
| 2026-04-15 12:00 |
20:24:56.59 |
-37:29:03.6 |
HIP 100584 |
13.14 |
| 2026-04-16 00:00 |
20:24:57.24 |
-37:29:14.6 |
HIP 100584 |
13.26 |