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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 22:46:34.41 | +10:42:21.8 | HIP 112574 | 23.43 |
| 2026-05-12 12:00 | 22:46:35.00 | +10:42:34.0 | HIP 112574 | 23.36 |
| 2026-05-13 00:00 | 22:46:35.57 | +10:42:46.2 | HIP 112574 | 23.30 |
| 2026-05-13 12:00 | 22:46:36.13 | +10:42:58.3 | HIP 112574 | 23.25 |
| 2026-05-14 00:00 | 22:46:36.67 | +10:43:10.4 | HIP 112574 | 23.20 |
| 2026-05-14 12:00 | 22:46:37.20 | +10:43:22.3 | HIP 112574 | 23.16 |
| 2026-05-15 00:00 | 22:46:37.72 | +10:43:34.3 | HIP 112574 | 23.12 |
| 2026-05-15 12:00 | 22:46:38.22 | +10:43:46.1 | HIP 112574 | 23.08 |
| 2026-05-16 00:00 | 22:46:38.70 | +10:43:57.9 | HIP 112574 | 23.06 |
| 2026-05-16 12:00 | 22:46:39.17 | +10:44:09.7 | HIP 112574 | 23.03 |
| 2026-05-17 00:00 | 22:46:39.63 | +10:44:21.4 | HIP 112574 | 23.02 |
| 2026-05-17 12:00 | 22:46:40.07 | +10:44:33.0 | HIP 112574 | 23.00 |
| 2026-05-18 00:00 | 22:46:40.50 | +10:44:44.6 | HIP 112574 | 23.00 |
| 2026-05-18 12:00 | 22:46:40.91 | +10:44:56.1 | HIP 112574 | 22.99 |
| 2026-05-19 00:00 | 22:46:41.31 | +10:45:07.5 | HIP 112574 | 22.99 |
| 2026-05-19 12:00 | 22:46:41.70 | +10:45:18.8 | HIP 112574 | 23.00 |
| 2026-05-20 00:00 | 22:46:42.06 | +10:45:30.1 | HIP 112574 | 23.01 |
| 2026-05-20 12:00 | 22:46:42.42 | +10:45:41.4 | HIP 112574 | 23.03 |
| 2026-05-21 00:00 | 22:46:42.76 | +10:45:52.5 | HIP 112574 | 23.05 |
| 2026-05-21 12:00 | 22:46:43.08 | +10:46:03.6 | HIP 112574 | 23.07 |
| 2026-05-22 00:00 | 22:46:43.39 | +10:46:14.6 | HIP 112574 | 23.10 |
| 2026-05-22 12:00 | 22:46:43.68 | +10:46:25.6 | HIP 112574 | 23.13 |
| 2026-05-23 00:00 | 22:46:43.96 | +10:46:36.5 | HIP 112574 | 23.17 |
| 2026-05-23 12:00 | 22:46:44.23 | +10:46:47.3 | HIP 112574 | 23.21 |
| 2026-05-24 00:00 | 22:46:44.48 | +10:46:58.0 | HIP 112574 | 23.25 |
| 2026-05-24 12:00 | 22:46:44.71 | +10:47:08.6 | HIP 112574 | 23.30 |
| 2026-05-25 00:00 | 22:46:44.93 | +10:47:19.2 | HIP 112574 | 23.36 |
| 2026-05-25 12:00 | 22:46:45.13 | +10:47:29.7 | HIP 112574 | 23.41 |
| 2026-05-26 00:00 | 22:46:45.32 | +10:47:40.2 | HIP 112574 | 23.47 |
| 2026-05-26 12:00 | 22:46:45.50 | +10:47:50.5 | HIP 112574 | 23.53 |
| 2026-05-27 00:00 | 22:46:45.66 | +10:48:00.8 | HIP 112574 | 23.60 |
| 2026-05-27 12:00 | 22:46:45.80 | +10:48:11.0 | HIP 112574 | 23.67 |
| 2026-05-28 00:00 | 22:46:45.93 | +10:48:21.1 | HIP 112574 | 23.74 |
| 2026-05-28 12:00 | 22:46:46.04 | +10:48:31.2 | HIP 112574 | 23.82 |
| 2026-05-29 00:00 | 22:46:46.14 | +10:48:41.1 | HIP 112574 | 23.90 |
| 2026-05-29 12:00 | 22:46:46.23 | +10:48:51.0 | HIP 112574 | 23.98 |
| 2026-05-30 00:00 | 22:46:46.30 | +10:49:00.8 | HIP 112574 | 24.07 |
| 2026-05-30 12:00 | 22:46:46.35 | +10:49:10.6 | HIP 112574 | 24.16 |
| 2026-05-31 00:00 | 22:46:46.39 | +10:49:20.2 | HIP 112574 | 24.25 |
| 2026-05-31 12:00 | 22:46:46.41 | +10:49:29.8 | HIP 112574 | 24.34 |
| 2026-06-01 00:00 | 22:46:46.42 | +10:49:39.2 | HIP 112574 | 24.44 |
| 2026-06-01 12:00 | 22:46:46.42 | +10:49:48.6 | HIP 112574 | 24.54 |
| 2026-06-02 00:00 | 22:46:46.40 | +10:49:58.0 | HIP 112574 | 24.64 |