C/2014 E2 (Jacques)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2014 E2 (Jacques) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2014-07-02T12:20:22.404480Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:32:50Z |
| Obs used | 4812 |
| NEO | - |
| M1 | 12.000 |
| K1 | 6.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2014-08-02.0000000 |
| e | 0.99903625 |
| q (au) | 0.663916 |
| a (au) | 688.887878 |
| i (deg) | 156.392754 |
| Ω (om, deg) | 56.391597 |
| ω (w, deg) | 344.037051 |
| M (ma, deg) | 0.001662 |
Magnitude
Scatter + Global Linear
$$ M_a = (11.111 + 3.563\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 11.111 |
| n | 3.563 |
| gf | 1.000 |
| gb | -0.909 |
| k | 0.991 |
| δ90 | 9.677 |
| 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 |
|---|---|---|---|
| 2014-02-23 | 2014-04-03 | +6.1865 | -2.097 |
| 2014-04-03 | 2014-06-29 | +14.8621 | -3.609 |
| 2014-07-08 | 2014-08-30 | +9.4649 | -1.555 |
| 2014-08-30 | 2015-06-08 | -2.1676 | -0.724 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 17:41:17.43 | -10:43:04.8 | HIP 86702 | 24.37 |
| 2026-09-20 12:00 | 17:41:17.47 | -10:43:19.0 | HIP 86702 | 24.32 |
| 2026-09-21 00:00 | 17:41:17.54 | -10:43:33.2 | HIP 86702 | 24.26 |
| 2026-09-21 12:00 | 17:41:17.65 | -10:43:47.3 | HIP 86702 | 24.20 |
| 2026-09-22 00:00 | 17:41:17.79 | -10:44:01.5 | HIP 86702 | 24.12 |
| 2026-09-22 12:00 | 17:41:17.96 | -10:44:15.7 | HIP 86702 | 24.05 |
| 2026-09-23 00:00 | 17:41:18.17 | -10:44:29.9 | HIP 86702 | 23.96 |
| 2026-09-23 12:00 | 17:41:18.42 | -10:44:44.1 | HIP 86702 | 23.87 |
| 2026-09-24 00:00 | 17:41:18.70 | -10:44:58.3 | HIP 86702 | 23.78 |
| 2026-09-24 12:00 | 17:41:19.02 | -10:45:12.5 | HIP 86702 | 23.67 |
| 2026-09-25 00:00 | 17:41:19.37 | -10:45:26.6 | HIP 86702 | 23.56 |
| 2026-09-25 12:00 | 17:41:19.75 | -10:45:40.8 | HIP 86702 | 23.45 |
| 2026-09-26 00:00 | 17:41:20.17 | -10:45:55.0 | HIP 86702 | 23.33 |
| 2026-09-26 12:00 | 17:41:20.63 | -10:46:09.1 | HIP 86702 | 23.20 |
| 2026-09-27 00:00 | 17:41:21.12 | -10:46:23.3 | HIP 86702 | 23.06 |
| 2026-09-27 12:00 | 17:41:21.64 | -10:46:37.4 | HIP 86702 | 22.92 |
| 2026-09-28 00:00 | 17:41:22.20 | -10:46:51.5 | HIP 86702 | 22.78 |
| 2026-09-28 12:00 | 17:41:22.79 | -10:47:05.6 | HIP 86702 | 22.62 |
| 2026-09-29 00:00 | 17:41:23.42 | -10:47:19.7 | HIP 86702 | 22.46 |
| 2026-09-29 12:00 | 17:41:24.08 | -10:47:33.8 | HIP 86702 | 22.30 |
| 2026-09-30 00:00 | 17:41:24.77 | -10:47:47.9 | HIP 86702 | 22.13 |
| 2026-09-30 12:00 | 17:41:25.50 | -10:48:02.0 | HIP 86702 | 21.95 |
| 2026-10-01 00:00 | 17:41:26.26 | -10:48:16.0 | HIP 86702 | 21.77 |
| 2026-10-01 12:00 | 17:41:27.06 | -10:48:30.1 | HIP 86702 | 21.58 |
| 2026-10-02 00:00 | 17:41:27.89 | -10:48:44.1 | HIP 86702 | 21.39 |
| 2026-10-02 12:00 | 17:41:28.76 | -10:48:58.1 | HIP 86702 | 21.19 |
| 2026-10-03 00:00 | 17:41:29.65 | -10:49:12.0 | HIP 86702 | 20.98 |
| 2026-10-03 12:00 | 17:41:30.59 | -10:49:26.0 | HIP 86702 | 20.77 |
| 2026-10-04 00:00 | 17:41:31.55 | -10:49:39.9 | HIP 86702 | 20.56 |
| 2026-10-04 12:00 | 17:41:32.55 | -10:49:53.8 | HIP 86702 | 20.34 |
| 2026-10-05 00:00 | 17:41:33.58 | -10:50:07.7 | HIP 86702 | 20.11 |
| 2026-10-05 12:00 | 17:41:34.65 | -10:50:21.6 | HIP 86702 | 19.88 |
| 2026-10-06 00:00 | 17:41:35.75 | -10:50:35.5 | HIP 86702 | 19.65 |
| 2026-10-06 12:00 | 17:41:36.88 | -10:50:49.3 | HIP 86702 | 19.41 |
| 2026-10-07 00:00 | 17:41:38.05 | -10:51:03.1 | HIP 86702 | 19.16 |
| 2026-10-07 12:00 | 17:41:39.25 | -10:51:16.8 | HIP 86702 | 18.92 |
| 2026-10-08 00:00 | 17:41:40.48 | -10:51:30.6 | HIP 86702 | 18.66 |
| 2026-10-08 12:00 | 17:41:41.74 | -10:51:44.3 | HIP 86702 | 18.41 |
| 2026-10-09 00:00 | 17:41:43.04 | -10:51:57.9 | HIP 86702 | 18.15 |
| 2026-10-09 12:00 | 17:41:44.37 | -10:52:11.6 | HIP 86702 | 17.89 |
| 2026-10-10 00:00 | 17:41:45.73 | -10:52:25.2 | HIP 86702 | 17.63 |
| 2026-10-10 12:00 | 17:41:47.13 | -10:52:38.7 | HIP 86702 | 17.36 |
| 2026-10-11 00:00 | 17:41:48.55 | -10:52:52.3 | HIP 86702 | 17.09 |