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
$$ M_a = (8.257 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.257 |
| n | 2.000 |
| gf | 1.000 |
| gb | -0.503 |
| 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 | 2019-11-10 | -2.4742 | +1.036 |
| 2019-11-11 | 2021-04-20 | +0.5916 | -0.832 |
| 2021-04-20 | 2022-05-28 | +2.9514 | -2.352 |
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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 13:42:49.00 | +14:34:08.6 | HIP 66974 | 16.67 |
| 2026-09-20 12:00 | 13:42:54.22 | +14:33:08.6 | HIP 66974 | 15.08 |
| 2026-09-21 00:00 | 13:42:59.47 | +14:32:08.9 | HIP 66974 | 13.49 |
| 2026-09-21 12:00 | 13:43:04.74 | +14:31:09.3 | HIP 66974 | 11.91 |
| 2026-09-22 00:00 | 13:43:10.03 | +14:30:10.0 | HIP 66974 | 10.34 |
| 2026-09-22 12:00 | 13:43:15.34 | +14:29:10.8 | HIP 66974 | 8.79 |
| 2026-09-23 00:00 | 13:43:20.67 | +14:28:11.9 | HIP 66974 | 7.26 |
| 2026-09-23 12:00 | 13:43:26.03 | +14:27:13.1 | HIP 66974 | 5.80 |
| 2026-09-24 00:00 | 13:43:31.40 | +14:26:14.6 | HIP 66974 | 4.44 |
| 2026-09-24 12:00 | 13:43:36.79 | +14:25:16.2 | HIP 66974 | 3.34 |
| 2026-09-25 00:00 | 13:43:42.21 | +14:24:18.1 | HIP 66974 | 2.82 |
| 2026-09-25 12:00 | 13:43:47.64 | +14:23:20.2 | HIP 66974 | 3.17 |
| 2026-09-26 00:00 | 13:43:53.09 | +14:22:22.6 | HIP 66974 | 4.19 |
| 2026-09-26 12:00 | 13:43:58.56 | +14:21:25.1 | HIP 66974 | 5.52 |
| 2026-09-27 00:00 | 13:44:04.05 | +14:20:27.8 | HIP 66974 | 6.98 |
| 2026-09-27 12:00 | 13:44:09.56 | +14:19:30.8 | HIP 66974 | 8.51 |
| 2026-09-28 00:00 | 13:44:15.09 | +14:18:34.0 | HIP 66974 | 10.07 |
| 2026-09-28 12:00 | 13:44:20.63 | +14:17:37.5 | HIP 66974 | 11.66 |
| 2026-09-29 00:00 | 13:44:26.19 | +14:16:41.1 | HIP 66976 | 13.20 |
| 2026-09-29 12:00 | 13:44:31.77 | +14:15:45.0 | HIP 66976 | 14.03 |
| 2026-09-30 00:00 | 13:44:37.36 | +14:14:49.2 | HIP 66976 | 15.00 |
| 2026-09-30 12:00 | 13:44:42.97 | +14:13:53.6 | HIP 66976 | 16.08 |
| 2026-10-01 00:00 | 13:44:48.59 | +14:12:58.2 | HIP 66976 | 17.26 |
| 2026-10-01 12:00 | 13:44:54.23 | +14:12:03.0 | HIP 66976 | 18.51 |
| 2026-10-02 00:00 | 13:44:59.89 | +14:11:08.1 | HIP 66976 | 19.83 |
| 2026-10-02 12:00 | 13:45:05.56 | +14:10:13.5 | HIP 67221 | 20.41 |
| 2026-10-03 00:00 | 13:45:11.25 | +14:09:19.1 | HIP 67221 | 19.24 |
| 2026-10-03 12:00 | 13:45:16.95 | +14:08:24.9 | HIP 67221 | 18.14 |
| 2026-10-04 00:00 | 13:45:22.66 | +14:07:31.0 | HIP 67221 | 17.12 |
| 2026-10-04 12:00 | 13:45:28.39 | +14:06:37.4 | HIP 67221 | 16.20 |
| 2026-10-05 00:00 | 13:45:34.13 | +14:05:44.0 | HIP 67221 | 15.39 |
| 2026-10-05 12:00 | 13:45:39.88 | +14:04:50.9 | HIP 67221 | 14.73 |
| 2026-10-06 00:00 | 13:45:45.64 | +14:03:58.0 | HIP 67221 | 14.22 |
| 2026-10-06 12:00 | 13:45:51.42 | +14:03:05.5 | HIP 67221 | 13.88 |
| 2026-10-07 00:00 | 13:45:57.21 | +14:02:13.1 | HIP 67221 | 13.73 |
| 2026-10-07 12:00 | 13:46:03.01 | +14:01:21.1 | HIP 67221 | 13.77 |
| 2026-10-08 00:00 | 13:46:08.82 | +14:00:29.3 | HIP 67221 | 14.01 |
| 2026-10-08 12:00 | 13:46:14.64 | +13:59:37.9 | HIP 67221 | 14.42 |
| 2026-10-09 00:00 | 13:46:20.47 | +13:58:46.7 | HIP 67221 | 15.00 |
| 2026-10-09 12:00 | 13:46:26.31 | +13:57:55.7 | HIP 67221 | 15.73 |
| 2026-10-10 00:00 | 13:46:32.16 | +13:57:05.1 | HIP 67221 | 16.59 |
| 2026-10-10 12:00 | 13:46:38.02 | +13:56:14.8 | HIP 67221 | 17.55 |
| 2026-10-11 00:00 | 13:46:43.88 | +13:55:24.7 | HIP 67221 | 18.61 |