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) |
|---|---|---|---|---|
| 2026-06-01 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 |
| 2026-06-02 12:00 | 22:46:46.36 | +10:50:07.2 | HIP 112574 | 24.74 |
| 2026-06-03 00:00 | 22:46:46.31 | +10:50:16.3 | HIP 112574 | 24.85 |
| 2026-06-03 12:00 | 22:46:46.24 | +10:50:25.4 | HIP 112574 | 24.96 |
| 2026-06-04 00:00 | 22:46:46.16 | +10:50:34.3 | HIP 112395 | 24.98 |
| 2026-06-04 12:00 | 22:46:46.07 | +10:50:43.2 | HIP 112395 | 24.84 |
| 2026-06-05 00:00 | 22:46:45.95 | +10:50:52.0 | HIP 112395 | 24.70 |
| 2026-06-05 12:00 | 22:46:45.83 | +10:51:00.7 | HIP 112395 | 24.56 |
| 2026-06-06 00:00 | 22:46:45.69 | +10:51:09.3 | HIP 112395 | 24.42 |
| 2026-06-06 12:00 | 22:46:45.53 | +10:51:17.9 | HIP 112395 | 24.28 |
| 2026-06-07 00:00 | 22:46:45.36 | +10:51:26.3 | HIP 112395 | 24.14 |
| 2026-06-07 12:00 | 22:46:45.17 | +10:51:34.6 | HIP 112395 | 24.00 |
| 2026-06-08 00:00 | 22:46:44.97 | +10:51:42.9 | HIP 112395 | 23.85 |
| 2026-06-08 12:00 | 22:46:44.75 | +10:51:51.0 | HIP 112395 | 23.71 |
| 2026-06-09 00:00 | 22:46:44.52 | +10:51:59.1 | HIP 112395 | 23.57 |
| 2026-06-09 12:00 | 22:46:44.27 | +10:52:07.1 | HIP 112395 | 23.42 |
| 2026-06-10 00:00 | 22:46:44.01 | +10:52:15.0 | HIP 112395 | 23.27 |
| 2026-06-10 12:00 | 22:46:43.73 | +10:52:22.7 | HIP 112395 | 23.13 |
| 2026-06-11 00:00 | 22:46:43.44 | +10:52:30.4 | HIP 112395 | 22.98 |
| 2026-06-11 12:00 | 22:46:43.13 | +10:52:38.0 | HIP 112395 | 22.83 |
| 2026-06-12 00:00 | 22:46:42.81 | +10:52:45.5 | HIP 112395 | 22.69 |
| 2026-06-12 12:00 | 22:46:42.47 | +10:52:52.9 | HIP 112395 | 22.54 |
| 2026-06-13 00:00 | 22:46:42.12 | +10:53:00.2 | HIP 112395 | 22.39 |
| 2026-06-13 12:00 | 22:46:41.76 | +10:53:07.4 | HIP 112395 | 22.24 |
| 2026-06-14 00:00 | 22:46:41.37 | +10:53:14.5 | HIP 112395 | 22.09 |
| 2026-06-14 12:00 | 22:46:40.98 | +10:53:21.5 | HIP 112395 | 21.94 |
| 2026-06-15 00:00 | 22:46:40.56 | +10:53:28.4 | HIP 112395 | 21.79 |
| 2026-06-15 12:00 | 22:46:40.14 | +10:53:35.2 | HIP 112395 | 21.64 |
| 2026-06-16 00:00 | 22:46:39.69 | +10:53:41.9 | HIP 112395 | 21.48 |
| 2026-06-16 12:00 | 22:46:39.24 | +10:53:48.5 | HIP 112395 | 21.33 |
| 2026-06-17 00:00 | 22:46:38.77 | +10:53:55.0 | HIP 112395 | 21.18 |
| 2026-06-17 12:00 | 22:46:38.28 | +10:54:01.4 | HIP 112395 | 21.03 |
| 2026-06-18 00:00 | 22:46:37.78 | +10:54:07.7 | HIP 112395 | 20.87 |
| 2026-06-18 12:00 | 22:46:37.26 | +10:54:13.9 | HIP 112395 | 20.72 |
| 2026-06-19 00:00 | 22:46:36.73 | +10:54:20.0 | HIP 112395 | 20.57 |
| 2026-06-19 12:00 | 22:46:36.19 | +10:54:25.9 | HIP 112395 | 20.41 |
| 2026-06-20 00:00 | 22:46:35.63 | +10:54:31.8 | HIP 112395 | 20.26 |
| 2026-06-20 12:00 | 22:46:35.05 | +10:54:37.6 | HIP 112395 | 20.11 |
| 2026-06-21 00:00 | 22:46:34.47 | +10:54:43.2 | HIP 112395 | 19.95 |
| 2026-06-21 12:00 | 22:46:33.86 | +10:54:48.8 | HIP 112395 | 19.80 |
| 2026-06-22 00:00 | 22:46:33.25 | +10:54:54.2 | HIP 112395 | 19.64 |