67P/Churyumov-Gerasimenko
Metadata
| Parameter | Value |
|---|---|
| Designation | 67P/Churyumov-Gerasimenko |
| Type | P |
| Perihelion (tp_cal, UTC) | 2015-08-13T02:07:40.042560Z |
| Orbit solution date (soln_date, UTC) | 2024-02-01T08:49:50Z |
| Obs used | 8608 |
| NEO | Yes |
| M1 | 12.900 |
| K1 | 7.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2015-10-10.0000000 |
| e | 0.64090813 |
| q (au) | 1.243266 |
| a (au) | 3.462249 |
| i (deg) | 7.040295 |
| Ω (om, deg) | 50.135574 |
| ω (w, deg) | 12.798250 |
| M (ma, deg) | 8.859927 |
Magnitude
Scatter + Global Linear
$$ M_a = (12.809 + 3.261\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 12.809 |
| n | 3.261 |
| gf | 0.959 |
| gb | -0.500 |
| k | 0.800 |
| δ90 | 1.384 |
| 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 |
|---|---|---|---|
| 2021-02-02 | 2023-04-26 | -0.2979 | -0.513 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 17:56:44.69 | -26:07:16.1 | HIP 87809 | 27.71 |
| 2026-03-26 12:00 | 17:56:50.31 | -26:07:37.5 | HIP 87809 | 28.38 |
| 2026-03-27 00:00 | 17:56:55.72 | -26:07:58.8 | HIP 87809 | 29.08 |
| 2026-03-27 12:00 | 17:57:00.93 | -26:08:20.3 | HIP 87809 | 29.80 |
| 2026-03-28 00:00 | 17:57:05.92 | -26:08:41.7 | HIP 87809 | 30.54 |
| 2026-03-28 12:00 | 17:57:10.71 | -26:09:03.2 | HIP 87809 | 31.29 |
| 2026-03-29 00:00 | 17:57:15.30 | -26:09:24.7 | HIP 87809 | 32.04 |
| 2026-03-29 12:00 | 17:57:19.67 | -26:09:46.3 | HIP 87809 | 32.78 |
| 2026-03-30 00:00 | 17:57:23.83 | -26:10:07.9 | HIP 88074 | 32.84 |
| 2026-03-30 12:00 | 17:57:27.78 | -26:10:29.6 | HIP 88074 | 32.40 |
| 2026-03-31 00:00 | 17:57:31.52 | -26:10:51.2 | HIP 88074 | 32.02 |
| 2026-03-31 12:00 | 17:57:35.05 | -26:11:13.0 | HIP 88074 | 31.69 |
| 2026-04-01 00:00 | 17:57:38.36 | -26:11:34.7 | HIP 88074 | 31.42 |
| 2026-04-01 12:00 | 17:57:41.46 | -26:11:56.5 | HIP 88074 | 31.20 |
| 2026-04-02 00:00 | 17:57:44.34 | -26:12:18.3 | HIP 88074 | 31.03 |
| 2026-04-02 12:00 | 17:57:47.01 | -26:12:40.2 | HIP 88074 | 30.91 |
| 2026-04-03 00:00 | 17:57:49.46 | -26:13:02.1 | HIP 88074 | 30.84 |
| 2026-04-03 12:00 | 17:57:51.69 | -26:13:24.0 | HIP 88074 | 30.81 |
| 2026-04-04 00:00 | 17:57:53.71 | -26:13:46.0 | HIP 88074 | 30.83 |
| 2026-04-04 12:00 | 17:57:55.50 | -26:14:08.0 | HIP 88074 | 30.88 |
| 2026-04-05 00:00 | 17:57:57.08 | -26:14:30.0 | HIP 88074 | 30.97 |
| 2026-04-05 12:00 | 17:57:58.43 | -26:14:52.1 | HIP 88074 | 31.10 |
| 2026-04-06 00:00 | 17:57:59.57 | -26:15:14.2 | HIP 88074 | 31.27 |
| 2026-04-06 12:00 | 17:58:00.47 | -26:15:36.3 | HIP 88074 | 31.47 |
| 2026-04-07 00:00 | 17:58:01.16 | -26:15:58.4 | HIP 88074 | 31.70 |
| 2026-04-07 12:00 | 17:58:01.62 | -26:16:20.6 | HIP 88074 | 31.95 |
| 2026-04-08 00:00 | 17:58:01.86 | -26:16:42.8 | HIP 88074 | 32.24 |
| 2026-04-08 12:00 | 17:58:01.87 | -26:17:05.0 | HIP 88074 | 32.56 |
| 2026-04-09 00:00 | 17:58:01.65 | -26:17:27.3 | HIP 88074 | 32.90 |
| 2026-04-09 12:00 | 17:58:01.21 | -26:17:49.6 | HIP 88074 | 33.27 |
| 2026-04-10 00:00 | 17:58:00.54 | -26:18:11.9 | HIP 88029 | 33.39 |
| 2026-04-10 12:00 | 17:57:59.64 | -26:18:34.2 | HIP 88029 | 33.10 |
| 2026-04-11 00:00 | 17:57:58.51 | -26:18:56.5 | HIP 88029 | 32.84 |
| 2026-04-11 12:00 | 17:57:57.15 | -26:19:18.9 | HIP 88029 | 32.60 |
| 2026-04-12 00:00 | 17:57:55.56 | -26:19:41.2 | HIP 88029 | 32.39 |
| 2026-04-12 12:00 | 17:57:53.73 | -26:20:03.6 | HIP 88029 | 32.20 |
| 2026-04-13 00:00 | 17:57:51.68 | -26:20:26.0 | HIP 88029 | 32.04 |
| 2026-04-13 12:00 | 17:57:49.39 | -26:20:48.4 | HIP 87824 | 31.87 |
| 2026-04-14 00:00 | 17:57:46.87 | -26:21:10.8 | HIP 87824 | 31.23 |
| 2026-04-14 12:00 | 17:57:44.12 | -26:21:33.2 | HIP 87824 | 30.57 |
| 2026-04-15 00:00 | 17:57:41.13 | -26:21:55.6 | HIP 87824 | 29.88 |
| 2026-04-15 12:00 | 17:57:37.91 | -26:22:18.0 | HIP 87824 | 29.16 |
| 2026-04-16 00:00 | 17:57:34.45 | -26:22:40.4 | HIP 87824 | 28.42 |