C/1989 W1 (Aarseth-Brewington)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1989 W1 (Aarseth-Brewington) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1989-12-27T21:19:34.193280Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:38Z |
| Obs used | 73 |
| NEO | - |
| M1 | 8.200 |
| K1 | 13.000 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 1989-12-05.0000000 |
| e | 1.00006499 |
| q (au) | 0.300689 |
| a (au) | -4626.812393 |
| i (deg) | 88.386281 |
| Ω (om, deg) | 345.916879 |
| ω (w, deg) | 205.258893 |
| M (ma, deg) | -0.000072 |
Magnitude
Scatter + Global Linear
$$ M_a = (7.015 + 3.263\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 7.015 |
| n | 3.263 |
| gf | 0.800 |
| 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 |
|---|---|---|---|
| 1989-09-01 | 1989-11-18 | +12.6569 | -0.458 |
| 1989-11-18 | 1989-12-04 | -0.1304 | -0.032 |
| 1989-12-04 | 1989-12-27 | -1.0598 | -0.450 |
| 1989-12-28 | 1990-01-31 | +0.3042 | +0.326 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 22:41:46.97 | +10:03:52.6 | HIP 112073 | 18.09 |
| 2026-02-03 12:00 | 22:41:48.61 | +10:03:58.4 | HIP 112073 | 18.11 |
| 2026-02-04 00:00 | 22:41:50.26 | +10:04:04.3 | HIP 112073 | 18.14 |
| 2026-02-04 12:00 | 22:41:51.91 | +10:04:10.4 | HIP 112073 | 18.18 |
| 2026-02-05 00:00 | 22:41:53.57 | +10:04:16.5 | HIP 112073 | 18.23 |
| 2026-02-05 12:00 | 22:41:55.23 | +10:04:22.7 | HIP 112073 | 18.30 |
| 2026-02-06 00:00 | 22:41:56.90 | +10:04:29.1 | HIP 112073 | 18.37 |
| 2026-02-06 12:00 | 22:41:58.58 | +10:04:35.5 | HIP 112073 | 18.46 |
| 2026-02-07 00:00 | 22:42:00.26 | +10:04:42.1 | HIP 112073 | 18.55 |
| 2026-02-07 12:00 | 22:42:01.95 | +10:04:48.8 | HIP 112073 | 18.66 |
| 2026-02-08 00:00 | 22:42:03.64 | +10:04:55.5 | HIP 112073 | 18.78 |
| 2026-02-08 12:00 | 22:42:05.34 | +10:05:02.4 | HIP 112073 | 18.91 |
| 2026-02-09 00:00 | 22:42:07.04 | +10:05:09.4 | HIP 112073 | 19.05 |
| 2026-02-09 12:00 | 22:42:08.75 | +10:05:16.5 | HIP 112073 | 19.20 |
| 2026-02-10 00:00 | 22:42:10.46 | +10:05:23.6 | HIP 112073 | 19.37 |
| 2026-02-10 12:00 | 22:42:12.18 | +10:05:30.9 | HIP 112073 | 19.54 |
| 2026-02-11 00:00 | 22:42:13.90 | +10:05:38.3 | HIP 112073 | 19.72 |
| 2026-02-11 12:00 | 22:42:15.63 | +10:05:45.8 | HIP 112073 | 19.91 |
| 2026-02-12 00:00 | 22:42:17.36 | +10:05:53.4 | HIP 112073 | 20.12 |
| 2026-02-12 12:00 | 22:42:19.09 | +10:06:01.1 | HIP 112073 | 20.33 |
| 2026-02-13 00:00 | 22:42:20.83 | +10:06:08.9 | HIP 112073 | 20.55 |
| 2026-02-13 12:00 | 22:42:22.58 | +10:06:16.7 | HIP 112073 | 20.78 |
| 2026-02-14 00:00 | 22:42:24.32 | +10:06:24.7 | HIP 112073 | 21.02 |
| 2026-02-14 12:00 | 22:42:26.07 | +10:06:32.8 | HIP 112073 | 21.27 |
| 2026-02-15 00:00 | 22:42:27.83 | +10:06:41.0 | HIP 112073 | 21.52 |
| 2026-02-15 12:00 | 22:42:29.58 | +10:06:49.3 | HIP 112073 | 21.79 |
| 2026-02-16 00:00 | 22:42:31.34 | +10:06:57.6 | HIP 112073 | 22.06 |
| 2026-02-16 12:00 | 22:42:33.11 | +10:07:06.1 | HIP 112073 | 22.34 |
| 2026-02-17 00:00 | 22:42:34.88 | +10:07:14.6 | HIP 112073 | 22.63 |
| 2026-02-17 12:00 | 22:42:36.64 | +10:07:23.3 | HIP 112073 | 22.92 |
| 2026-02-18 00:00 | 22:42:38.42 | +10:07:32.0 | HIP 112073 | 23.22 |
| 2026-02-18 12:00 | 22:42:40.19 | +10:07:40.9 | HIP 112073 | 23.53 |
| 2026-02-19 00:00 | 22:42:41.97 | +10:07:49.8 | HIP 112073 | 23.85 |
| 2026-02-19 12:00 | 22:42:43.75 | +10:07:58.8 | HIP 112073 | 24.17 |
| 2026-02-20 00:00 | 22:42:45.53 | +10:08:07.9 | HIP 112073 | 24.50 |
| 2026-02-20 12:00 | 22:42:47.31 | +10:08:17.1 | HIP 112073 | 24.83 |
| 2026-02-21 00:00 | 22:42:49.10 | +10:08:26.4 | HIP 112073 | 25.17 |
| 2026-02-21 12:00 | 22:42:50.89 | +10:08:35.8 | HIP 112073 | 25.51 |
| 2026-02-22 00:00 | 22:42:52.68 | +10:08:45.2 | HIP 112073 | 25.86 |
| 2026-02-22 12:00 | 22:42:54.47 | +10:08:54.8 | HIP 112073 | 26.22 |
| 2026-02-23 00:00 | 22:42:56.26 | +10:09:04.4 | HIP 112073 | 26.58 |
| 2026-02-23 12:00 | 22:42:58.05 | +10:09:14.1 | HIP 112073 | 26.94 |
| 2026-02-24 00:00 | 22:42:59.84 | +10:09:23.9 | HIP 112073 | 27.31 |