C/2010 X1 (Elenin)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2010 X1 (Elenin) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2011-09-10T17:16:26.166720Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:31:47Z |
| Obs used | 2235 |
| NEO | - |
| M1 | 12.600 |
| K1 | 6.250 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2011-03-31.0000000 |
| e | 1.00006725 |
| q (au) | 0.482421 |
| a (au) | -7173.388485 |
| i (deg) | 1.839568 |
| Ω (om, deg) | 323.235147 |
| ω (w, deg) | 343.798118 |
| M (ma, deg) | -0.000266 |
Magnitude
Scatter + Global Linear
$$ M_a = (12.212 + 2.745\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 12.212 |
| n | 2.745 |
| gf | 0.800 |
| gb | -0.772 |
| k | 0.993 |
| 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 |
|---|---|---|---|
| 2010-12-10 | 2011-07-01 | +1.4907 | -0.743 |
| 2011-07-01 | 2011-08-03 | +16.9717 | -4.126 |
| 2011-08-03 | 2011-09-07 | -9.5074 | -4.344 |
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 | 07:46:16.58 | +22:06:33.3 | HIP 37986 | 11.83 |
| 2026-09-20 12:00 | 07:46:18.30 | +22:06:29.6 | HIP 37986 | 11.43 |
| 2026-09-21 00:00 | 07:46:20.00 | +22:06:26.1 | HIP 37986 | 11.04 |
| 2026-09-21 12:00 | 07:46:21.67 | +22:06:22.6 | HIP 37986 | 10.65 |
| 2026-09-22 00:00 | 07:46:23.31 | +22:06:19.1 | HIP 37986 | 10.27 |
| 2026-09-22 12:00 | 07:46:24.92 | +22:06:15.8 | HIP 37986 | 9.90 |
| 2026-09-23 00:00 | 07:46:26.51 | +22:06:12.5 | HIP 37986 | 9.53 |
| 2026-09-23 12:00 | 07:46:28.07 | +22:06:09.3 | HIP 37986 | 9.17 |
| 2026-09-24 00:00 | 07:46:29.60 | +22:06:06.2 | HIP 37986 | 8.82 |
| 2026-09-24 12:00 | 07:46:31.10 | +22:06:03.1 | HIP 37986 | 8.47 |
| 2026-09-25 00:00 | 07:46:32.58 | +22:06:00.1 | HIP 37986 | 8.13 |
| 2026-09-25 12:00 | 07:46:34.02 | +22:05:57.2 | HIP 37986 | 7.80 |
| 2026-09-26 00:00 | 07:46:35.44 | +22:05:54.4 | HIP 37986 | 7.47 |
| 2026-09-26 12:00 | 07:46:36.83 | +22:05:51.6 | HIP 37986 | 7.16 |
| 2026-09-27 00:00 | 07:46:38.19 | +22:05:48.9 | HIP 37986 | 6.85 |
| 2026-09-27 12:00 | 07:46:39.52 | +22:05:46.3 | HIP 37986 | 6.54 |
| 2026-09-28 00:00 | 07:46:40.83 | +22:05:43.8 | HIP 37986 | 6.25 |
| 2026-09-28 12:00 | 07:46:42.10 | +22:05:41.3 | HIP 37986 | 5.96 |
| 2026-09-29 00:00 | 07:46:43.35 | +22:05:38.9 | HIP 37986 | 5.67 |
| 2026-09-29 12:00 | 07:46:44.56 | +22:05:36.6 | HIP 37986 | 5.40 |
| 2026-09-30 00:00 | 07:46:45.75 | +22:05:34.3 | HIP 37986 | 5.13 |
| 2026-09-30 12:00 | 07:46:46.91 | +22:05:32.2 | HIP 37986 | 4.87 |
| 2026-10-01 00:00 | 07:46:48.04 | +22:05:30.1 | HIP 37986 | 4.62 |
| 2026-10-01 12:00 | 07:46:49.14 | +22:05:28.1 | HIP 37986 | 4.38 |
| 2026-10-02 00:00 | 07:46:50.21 | +22:05:26.1 | HIP 37986 | 4.15 |
| 2026-10-02 12:00 | 07:46:51.25 | +22:05:24.3 | HIP 37986 | 3.92 |
| 2026-10-03 00:00 | 07:46:52.26 | +22:05:22.5 | HIP 37986 | 3.70 |
| 2026-10-03 12:00 | 07:46:53.24 | +22:05:20.8 | HIP 37986 | 3.49 |
| 2026-10-04 00:00 | 07:46:54.19 | +22:05:19.1 | HIP 37986 | 3.29 |
| 2026-10-04 12:00 | 07:46:55.11 | +22:05:17.6 | HIP 37986 | 3.10 |
| 2026-10-05 00:00 | 07:46:56.00 | +22:05:16.1 | HIP 37986 | 2.91 |
| 2026-10-05 12:00 | 07:46:56.86 | +22:05:14.7 | HIP 37986 | 2.74 |
| 2026-10-06 00:00 | 07:46:57.68 | +22:05:13.4 | HIP 37986 | 2.58 |
| 2026-10-06 12:00 | 07:46:58.48 | +22:05:12.2 | HIP 37986 | 2.42 |
| 2026-10-07 00:00 | 07:46:59.25 | +22:05:11.0 | HIP 37986 | 2.28 |
| 2026-10-07 12:00 | 07:46:59.99 | +22:05:09.9 | HIP 37986 | 2.14 |
| 2026-10-08 00:00 | 07:47:00.69 | +22:05:08.9 | HIP 37986 | 2.02 |
| 2026-10-08 12:00 | 07:47:01.36 | +22:05:08.0 | HIP 37986 | 1.91 |
| 2026-10-09 00:00 | 07:47:02.01 | +22:05:07.2 | HIP 37986 | 1.81 |
| 2026-10-09 12:00 | 07:47:02.62 | +22:05:06.4 | HIP 37986 | 1.72 |
| 2026-10-10 00:00 | 07:47:03.20 | +22:05:05.7 | HIP 37986 | 1.64 |
| 2026-10-10 12:00 | 07:47:03.75 | +22:05:05.1 | HIP 37986 | 1.57 |
| 2026-10-11 00:00 | 07:47:04.27 | +22:05:04.6 | HIP 37986 | 1.51 |