88P/Howell
Metadata
| Parameter | Value |
|---|---|
| Designation | 88P/Howell |
| Type | P |
| Perihelion (tp_cal, UTC) | 2020-09-26T14:34:20.904960Z |
| Orbit solution date (soln_date, UTC) | 2026-09-21T09:57:33Z |
| Obs used | 3675 |
| NEO | - |
| M1 | 11.400 |
| K1 | 10.500 |
| PC | 0.030 |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-08-24.0000000 |
| e | 0.56435193 |
| q (au) | 1.353072 |
| a (au) | 3.105882 |
| i (deg) | 4.383943 |
| Ω (om, deg) | 56.685062 |
| ω (w, deg) | 235.913306 |
| M (ma, deg) | 353.948559 |
Magnitude
Scatter + Global Linear
$$ M_a = (7.157 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 7.157 |
| n | 6.000 |
| gf | 1.000 |
| gb | -1.000 |
| 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 |
|---|---|---|---|
| 2023-11-23 | 2026-06-27 | -0.0217 | -1.045 |
| 2026-06-27 | 2026-08-14 | +11.6009 | -3.502 |
| 2026-08-14 | 2026-09-26 | +1.6587 | -0.209 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 03:15:16.06 | +15:00:13.7 | HIP 15137 | 6.71 |
| 2026-09-20 12:00 | 03:15:04.43 | +14:59:51.3 | HIP 15137 | 6.12 |
| 2026-09-21 00:00 | 03:14:52.29 | +14:59:27.3 | HIP 15137 | 6.83 |
| 2026-09-21 12:00 | 03:14:39.65 | +14:59:01.5 | HIP 15137 | 8.64 |
| 2026-09-22 00:00 | 03:14:26.50 | +14:58:34.1 | HIP 15137 | 11.14 |
| 2026-09-22 12:00 | 03:14:12.84 | +14:58:05.0 | HIP 15137 | 14.03 |
| 2026-09-23 00:00 | 03:13:58.69 | +14:57:34.2 | HIP 15137 | 17.20 |
| 2026-09-23 12:00 | 03:13:44.04 | +14:57:01.7 | HIP 14909 | 19.91 |
| 2026-09-24 00:00 | 03:13:28.89 | +14:56:27.5 | HIP 14909 | 16.63 |
| 2026-09-24 12:00 | 03:13:13.25 | +14:55:51.7 | HIP 14909 | 13.47 |
| 2026-09-25 00:00 | 03:12:57.12 | +14:55:14.3 | HIP 14909 | 10.70 |
| 2026-09-25 12:00 | 03:12:40.51 | +14:54:35.1 | HIP 14909 | 8.83 |
| 2026-09-26 00:00 | 03:12:23.41 | +14:53:54.4 | HIP 14909 | 8.66 |
| 2026-09-26 12:00 | 03:12:05.83 | +14:53:12.0 | HIP 14909 | 10.43 |
| 2026-09-27 00:00 | 03:11:47.77 | +14:52:27.9 | HIP 14909 | 13.50 |
| 2026-09-27 12:00 | 03:11:29.25 | +14:51:42.3 | HIP 14909 | 17.27 |
| 2026-09-28 00:00 | 03:11:10.25 | +14:50:55.0 | HIP 14909 | 21.46 |
| 2026-09-28 12:00 | 03:10:50.78 | +14:50:06.1 | HIP 14909 | 25.91 |
| 2026-09-29 00:00 | 03:10:30.86 | +14:49:15.6 | HIP 14909 | 30.58 |
| 2026-09-29 12:00 | 03:10:10.47 | +14:48:23.6 | HIP 14705 | 34.14 |
| 2026-09-30 00:00 | 03:09:49.63 | +14:47:29.9 | HIP 14705 | 35.02 |
| 2026-09-30 12:00 | 03:09:28.34 | +14:46:34.7 | HIP 14614 | 35.19 |
| 2026-10-01 00:00 | 03:09:06.61 | +14:45:37.9 | HIP 14614 | 34.91 |
| 2026-10-01 12:00 | 03:08:44.43 | +14:44:39.5 | HIP 14497 | 34.72 |
| 2026-10-02 00:00 | 03:08:21.82 | +14:43:39.6 | HIP 14497 | 32.56 |
| 2026-10-02 12:00 | 03:07:58.78 | +14:42:38.2 | HIP 14497 | 31.24 |
| 2026-10-03 00:00 | 03:07:35.31 | +14:41:35.3 | HIP 14497 | 30.92 |
| 2026-10-03 12:00 | 03:07:11.42 | +14:40:30.8 | HIP 14497 | 31.70 |
| 2026-10-04 00:00 | 03:06:47.11 | +14:39:24.9 | HIP 14404 | 27.42 |
| 2026-10-04 12:00 | 03:06:22.39 | +14:38:17.5 | HIP 14404 | 23.76 |
| 2026-10-05 00:00 | 03:05:57.27 | +14:37:08.6 | HIP 14404 | 21.21 |
| 2026-10-05 12:00 | 03:05:31.75 | +14:35:58.3 | HIP 14404 | 20.28 |
| 2026-10-06 00:00 | 03:05:05.84 | +14:34:46.6 | HIP 14404 | 21.29 |
| 2026-10-06 12:00 | 03:04:39.55 | +14:33:33.4 | HIP 14236 | 16.88 |
| 2026-10-07 00:00 | 03:04:12.87 | +14:32:18.9 | HIP 14236 | 10.40 |
| 2026-10-07 12:00 | 03:03:45.83 | +14:31:03.0 | HIP 14236 | 4.12 |
| 2026-10-08 00:00 | 03:03:18.42 | +14:29:45.8 | HIP 14236 | 3.92 |
| 2026-10-08 12:00 | 03:02:50.66 | +14:28:27.3 | HIP 14236 | 10.33 |
| 2026-10-09 00:00 | 03:02:22.55 | +14:27:07.4 | HIP 14236 | 17.17 |
| 2026-10-09 12:00 | 03:01:54.09 | +14:25:46.3 | HIP 14236 | 24.15 |
| 2026-10-10 00:00 | 03:01:25.31 | +14:24:24.0 | HIP 14236 | 31.23 |
| 2026-10-10 12:00 | 03:00:56.20 | +14:23:00.4 | HIP 14069 | 36.30 |
| 2026-10-11 00:00 | 03:00:26.77 | +14:21:35.6 | HIP 14069 | 39.29 |