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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 22:42:06.83 | +10:41:44.7 | HIP 112056 | 11.59 |
| 2026-09-20 12:00 | 22:42:05.10 | +10:41:32.3 | HIP 112056 | 11.23 |
| 2026-09-21 00:00 | 22:42:03.38 | +10:41:19.8 | HIP 112056 | 10.89 |
| 2026-09-21 12:00 | 22:42:01.66 | +10:41:07.2 | HIP 112056 | 10.55 |
| 2026-09-22 00:00 | 22:41:59.94 | +10:40:54.7 | HIP 112056 | 10.22 |
| 2026-09-22 12:00 | 22:41:58.23 | +10:40:42.0 | HIP 112056 | 9.91 |
| 2026-09-23 00:00 | 22:41:56.53 | +10:40:29.3 | HIP 112056 | 9.61 |
| 2026-09-23 12:00 | 22:41:54.83 | +10:40:16.6 | HIP 112056 | 9.32 |
| 2026-09-24 00:00 | 22:41:53.14 | +10:40:03.9 | HIP 112056 | 9.04 |
| 2026-09-24 12:00 | 22:41:51.45 | +10:39:51.1 | HIP 112056 | 8.78 |
| 2026-09-25 00:00 | 22:41:49.77 | +10:39:38.2 | HIP 112056 | 8.54 |
| 2026-09-25 12:00 | 22:41:48.09 | +10:39:25.3 | HIP 112056 | 8.32 |
| 2026-09-26 00:00 | 22:41:46.43 | +10:39:12.4 | HIP 112056 | 8.12 |
| 2026-09-26 12:00 | 22:41:44.77 | +10:38:59.5 | HIP 112056 | 7.93 |
| 2026-09-27 00:00 | 22:41:43.11 | +10:38:46.5 | HIP 112056 | 7.77 |
| 2026-09-27 12:00 | 22:41:41.46 | +10:38:33.5 | HIP 112056 | 7.64 |
| 2026-09-28 00:00 | 22:41:39.82 | +10:38:20.4 | HIP 112056 | 7.52 |
| 2026-09-28 12:00 | 22:41:38.19 | +10:38:07.3 | HIP 112056 | 7.44 |
| 2026-09-29 00:00 | 22:41:36.56 | +10:37:54.2 | HIP 112056 | 7.38 |
| 2026-09-29 12:00 | 22:41:34.94 | +10:37:41.0 | HIP 112056 | 7.34 |
| 2026-09-30 00:00 | 22:41:33.33 | +10:37:27.8 | HIP 112056 | 7.33 |
| 2026-09-30 12:00 | 22:41:31.73 | +10:37:14.6 | HIP 112056 | 7.35 |
| 2026-10-01 00:00 | 22:41:30.13 | +10:37:01.4 | HIP 112056 | 7.40 |
| 2026-10-01 12:00 | 22:41:28.54 | +10:36:48.1 | HIP 112056 | 7.47 |
| 2026-10-02 00:00 | 22:41:26.96 | +10:36:34.8 | HIP 112056 | 7.56 |
| 2026-10-02 12:00 | 22:41:25.39 | +10:36:21.5 | HIP 112056 | 7.68 |
| 2026-10-03 00:00 | 22:41:23.82 | +10:36:08.1 | HIP 112056 | 7.82 |
| 2026-10-03 12:00 | 22:41:22.26 | +10:35:54.8 | HIP 112056 | 7.98 |
| 2026-10-04 00:00 | 22:41:20.71 | +10:35:41.4 | HIP 112056 | 8.16 |
| 2026-10-04 12:00 | 22:41:19.17 | +10:35:28.0 | HIP 112056 | 8.36 |
| 2026-10-05 00:00 | 22:41:17.64 | +10:35:14.5 | HIP 112056 | 8.57 |
| 2026-10-05 12:00 | 22:41:16.12 | +10:35:01.1 | HIP 112056 | 8.80 |
| 2026-10-06 00:00 | 22:41:14.61 | +10:34:47.6 | HIP 112056 | 9.04 |
| 2026-10-06 12:00 | 22:41:13.10 | +10:34:34.1 | HIP 112056 | 9.30 |
| 2026-10-07 00:00 | 22:41:11.60 | +10:34:20.6 | HIP 112056 | 9.56 |
| 2026-10-07 12:00 | 22:41:10.12 | +10:34:07.1 | HIP 112056 | 9.83 |
| 2026-10-08 00:00 | 22:41:08.64 | +10:33:53.5 | HIP 112056 | 10.11 |
| 2026-10-08 12:00 | 22:41:07.17 | +10:33:40.0 | HIP 112056 | 10.40 |
| 2026-10-09 00:00 | 22:41:05.71 | +10:33:26.4 | HIP 112056 | 10.70 |
| 2026-10-09 12:00 | 22:41:04.26 | +10:33:12.9 | HIP 112056 | 11.00 |
| 2026-10-10 00:00 | 22:41:02.83 | +10:32:59.3 | HIP 112056 | 11.31 |
| 2026-10-10 12:00 | 22:41:01.40 | +10:32:45.7 | HIP 112056 | 11.62 |
| 2026-10-11 00:00 | 22:40:59.98 | +10:32:32.1 | HIP 112056 | 11.94 |