C/2018 N2 (ASASSN)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2018 N2 (ASASSN) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2019-11-10T23:08:28.780800Z |
| Orbit solution date (soln_date, UTC) | 2022-12-31T16:12:33Z |
| Obs used | 4653 |
| NEO | - |
| M1 | 9.600 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2018-07-07T09:19:02.208000Z |
| Discovery magnitude (MPC) | 16.40 V |
| Discovery observatory (MPC) | W87 · Cerro Tololo-LCO C |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-02-26.0000000 |
| e | 1.00018357 |
| q (au) | 3.124659 |
| a (au) | -17021.931787 |
| i (deg) | 77.530043 |
| Ω (om, deg) | 25.257801 |
| ω (w, deg) | 24.397034 |
| M (ma, deg) | 0.000048 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.258 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.258 |
| n | 2.000 |
| gf | 0.999 |
| gb | -0.500 |
| 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 |
|---|---|---|---|
| 2017-10-27 | 2018-08-12 | -26.1850 | +18.320 |
| 2018-08-12 | 2019-11-10 | -2.3664 | +0.987 |
| 2019-11-11 | 2021-04-20 | +0.5708 | -0.818 |
| 2021-04-20 | 2022-05-28 | +2.9575 | -2.358 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 14:03:48.78 | +16:26:52.4 | HIP 68809 | 25.43 |
| 2026-02-03 12:00 | 14:03:47.13 | +16:27:35.6 | HIP 68809 | 25.35 |
| 2026-02-04 00:00 | 14:03:45.41 | +16:28:18.9 | HIP 68809 | 25.31 |
| 2026-02-04 12:00 | 14:03:43.64 | +16:29:02.5 | HIP 68809 | 25.31 |
| 2026-02-05 00:00 | 14:03:41.80 | +16:29:46.3 | HIP 68809 | 25.34 |
| 2026-02-05 12:00 | 14:03:39.90 | +16:30:30.3 | HIP 68809 | 25.42 |
| 2026-02-06 00:00 | 14:03:37.93 | +16:31:14.4 | HIP 68809 | 25.54 |
| 2026-02-06 12:00 | 14:03:35.91 | +16:31:58.8 | HIP 68809 | 25.70 |
| 2026-02-07 00:00 | 14:03:33.81 | +16:32:43.4 | HIP 68809 | 25.91 |
| 2026-02-07 12:00 | 14:03:31.66 | +16:33:28.1 | HIP 68809 | 26.15 |
| 2026-02-08 00:00 | 14:03:29.44 | +16:34:13.1 | HIP 68809 | 26.44 |
| 2026-02-08 12:00 | 14:03:27.16 | +16:34:58.2 | HIP 68809 | 26.77 |
| 2026-02-09 00:00 | 14:03:24.82 | +16:35:43.5 | HIP 68809 | 27.14 |
| 2026-02-09 12:00 | 14:03:22.42 | +16:36:28.9 | HIP 68517 | 26.73 |
| 2026-02-10 00:00 | 14:03:19.95 | +16:37:14.5 | HIP 68517 | 25.93 |
| 2026-02-10 12:00 | 14:03:17.42 | +16:38:00.3 | HIP 68517 | 25.11 |
| 2026-02-11 00:00 | 14:03:14.83 | +16:38:46.2 | HIP 68517 | 24.30 |
| 2026-02-11 12:00 | 14:03:12.18 | +16:39:32.2 | HIP 68517 | 23.48 |
| 2026-02-12 00:00 | 14:03:09.46 | +16:40:18.4 | HIP 68517 | 22.67 |
| 2026-02-12 12:00 | 14:03:06.68 | +16:41:04.8 | HIP 68517 | 21.85 |
| 2026-02-13 00:00 | 14:03:03.84 | +16:41:51.2 | HIP 68517 | 21.04 |
| 2026-02-13 12:00 | 14:03:00.94 | +16:42:37.8 | HIP 68517 | 20.23 |
| 2026-02-14 00:00 | 14:02:57.98 | +16:43:24.5 | HIP 68517 | 19.43 |
| 2026-02-14 12:00 | 14:02:54.96 | +16:44:11.4 | HIP 68517 | 18.64 |
| 2026-02-15 00:00 | 14:02:51.87 | +16:44:58.3 | HIP 68517 | 17.87 |
| 2026-02-15 12:00 | 14:02:48.73 | +16:45:45.3 | HIP 68517 | 17.11 |
| 2026-02-16 00:00 | 14:02:45.52 | +16:46:32.4 | HIP 68517 | 16.37 |
| 2026-02-16 12:00 | 14:02:42.25 | +16:47:19.7 | HIP 68517 | 15.67 |
| 2026-02-17 00:00 | 14:02:38.93 | +16:48:07.0 | HIP 68517 | 15.00 |
| 2026-02-17 12:00 | 14:02:35.54 | +16:48:54.4 | HIP 68517 | 14.37 |
| 2026-02-18 00:00 | 14:02:32.09 | +16:49:41.8 | HIP 68517 | 13.79 |
| 2026-02-18 12:00 | 14:02:28.58 | +16:50:29.4 | HIP 68517 | 13.27 |
| 2026-02-19 00:00 | 14:02:25.02 | +16:51:16.9 | HIP 68517 | 12.83 |
| 2026-02-19 12:00 | 14:02:21.39 | +16:52:04.6 | HIP 68517 | 12.46 |
| 2026-02-20 00:00 | 14:02:17.71 | +16:52:52.3 | HIP 68517 | 12.19 |
| 2026-02-20 12:00 | 14:02:13.97 | +16:53:40.0 | HIP 68517 | 12.02 |
| 2026-02-21 00:00 | 14:02:10.17 | +16:54:27.8 | HIP 68517 | 11.96 |
| 2026-02-21 12:00 | 14:02:06.31 | +16:55:15.7 | HIP 68517 | 12.02 |
| 2026-02-22 00:00 | 14:02:02.39 | +16:56:03.5 | HIP 68517 | 12.19 |
| 2026-02-22 12:00 | 14:01:58.42 | +16:56:51.4 | HIP 68517 | 12.47 |
| 2026-02-23 00:00 | 14:01:54.39 | +16:57:39.3 | HIP 68517 | 12.87 |
| 2026-02-23 12:00 | 14:01:50.30 | +16:58:27.1 | HIP 68517 | 13.36 |
| 2026-02-24 00:00 | 14:01:46.16 | +16:59:15.0 | HIP 68517 | 13.96 |