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 | 1989-11-19 | +12.2046 | -0.330 |
| 1989-11-19 | 1989-12-04 | -0.1288 | -0.034 |
| 1989-12-04 | 1989-12-27 | -1.0628 | -0.451 |
| 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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 22:44:44.59 | +10:21:15.0 | HIP 112380 | 14.54 |
| 2026-03-26 12:00 | 22:44:46.21 | +10:21:28.4 | HIP 112380 | 14.24 |
| 2026-03-27 00:00 | 22:44:47.82 | +10:21:41.8 | HIP 112380 | 13.94 |
| 2026-03-27 12:00 | 22:44:49.42 | +10:21:55.2 | HIP 112380 | 13.66 |
| 2026-03-28 00:00 | 22:44:51.02 | +10:22:08.7 | HIP 112380 | 13.40 |
| 2026-03-28 12:00 | 22:44:52.61 | +10:22:22.2 | HIP 112380 | 13.14 |
| 2026-03-29 00:00 | 22:44:54.20 | +10:22:35.7 | HIP 112380 | 12.89 |
| 2026-03-29 12:00 | 22:44:55.77 | +10:22:49.2 | HIP 112380 | 12.66 |
| 2026-03-30 00:00 | 22:44:57.34 | +10:23:02.8 | HIP 112380 | 12.44 |
| 2026-03-30 12:00 | 22:44:58.90 | +10:23:16.4 | HIP 112380 | 12.24 |
| 2026-03-31 00:00 | 22:45:00.46 | +10:23:30.0 | HIP 112380 | 12.05 |
| 2026-03-31 12:00 | 22:45:02.00 | +10:23:43.6 | HIP 112380 | 11.88 |
| 2026-04-01 00:00 | 22:45:03.54 | +10:23:57.3 | HIP 112380 | 11.72 |
| 2026-04-01 12:00 | 22:45:05.07 | +10:24:11.0 | HIP 112380 | 11.58 |
| 2026-04-02 00:00 | 22:45:06.60 | +10:24:24.7 | HIP 112380 | 11.45 |
| 2026-04-02 12:00 | 22:45:08.11 | +10:24:38.4 | HIP 112380 | 11.35 |
| 2026-04-03 00:00 | 22:45:09.62 | +10:24:52.1 | HIP 112380 | 11.26 |
| 2026-04-03 12:00 | 22:45:11.12 | +10:25:05.9 | HIP 112380 | 11.19 |
| 2026-04-04 00:00 | 22:45:12.61 | +10:25:19.7 | HIP 112380 | 11.13 |
| 2026-04-04 12:00 | 22:45:14.09 | +10:25:33.4 | HIP 112380 | 11.10 |
| 2026-04-05 00:00 | 22:45:15.56 | +10:25:47.2 | HIP 112380 | 11.08 |
| 2026-04-05 12:00 | 22:45:17.02 | +10:26:01.0 | HIP 112380 | 11.08 |
| 2026-04-06 00:00 | 22:45:18.48 | +10:26:14.9 | HIP 112380 | 11.10 |
| 2026-04-06 12:00 | 22:45:19.93 | +10:26:28.7 | HIP 112380 | 11.13 |
| 2026-04-07 00:00 | 22:45:21.37 | +10:26:42.6 | HIP 112380 | 11.18 |
| 2026-04-07 12:00 | 22:45:22.79 | +10:26:56.4 | HIP 112380 | 11.25 |
| 2026-04-08 00:00 | 22:45:24.21 | +10:27:10.3 | HIP 112380 | 11.34 |
| 2026-04-08 12:00 | 22:45:25.62 | +10:27:24.1 | HIP 112380 | 11.44 |
| 2026-04-09 00:00 | 22:45:27.03 | +10:27:38.0 | HIP 112380 | 11.55 |
| 2026-04-09 12:00 | 22:45:28.42 | +10:27:51.9 | HIP 112380 | 11.68 |
| 2026-04-10 00:00 | 22:45:29.80 | +10:28:05.8 | HIP 112380 | 11.83 |
| 2026-04-10 12:00 | 22:45:31.17 | +10:28:19.7 | HIP 112380 | 11.98 |
| 2026-04-11 00:00 | 22:45:32.54 | +10:28:33.6 | HIP 112380 | 12.15 |
| 2026-04-11 12:00 | 22:45:33.89 | +10:28:47.5 | HIP 112380 | 12.33 |
| 2026-04-12 00:00 | 22:45:35.23 | +10:29:01.4 | HIP 112380 | 12.52 |
| 2026-04-12 12:00 | 22:45:36.56 | +10:29:15.3 | HIP 112380 | 12.72 |
| 2026-04-13 00:00 | 22:45:37.89 | +10:29:29.2 | HIP 112380 | 12.93 |
| 2026-04-13 12:00 | 22:45:39.20 | +10:29:43.1 | HIP 112380 | 13.15 |
| 2026-04-14 00:00 | 22:45:40.50 | +10:29:57.0 | HIP 112380 | 13.38 |
| 2026-04-14 12:00 | 22:45:41.79 | +10:30:10.9 | HIP 112380 | 13.62 |
| 2026-04-15 00:00 | 22:45:43.08 | +10:30:24.8 | HIP 112380 | 13.86 |
| 2026-04-15 12:00 | 22:45:44.35 | +10:30:38.7 | HIP 112380 | 14.11 |
| 2026-04-16 00:00 | 22:45:45.61 | +10:30:52.6 | HIP 112380 | 14.36 |