88P/Howell
Metadata
| Parameter | Value |
|---|---|
| Designation | 88P/Howell |
| Type | P |
| Perihelion (tp_cal, UTC) | 2020-09-26T13:40:03.884160Z |
| Orbit solution date (soln_date, UTC) | 2026-03-31T13:31:44Z |
| Obs used | 1856 |
| NEO | - |
| M1 | 12.000 |
| K1 | 9.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2021-07-16.0000000 |
| e | 0.56422712 |
| q (au) | 1.353101 |
| a (au) | 3.105060 |
| i (deg) | 4.383848 |
| Ω (om, deg) | 56.679891 |
| ω (w, deg) | 235.900544 |
| M (ma, deg) | 52.677077 |
Magnitude
Scatter + Global Linear
$$ M_a = (7.579 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 7.579 |
| n | 6.000 |
| gf | 1.000 |
| 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 |
|---|---|---|---|
| 2023-11-23 | 2025-05-17 | +6.0580 | -2.103 |
| 2025-05-17 | 2025-01-26 | -8.9416 | +4.822 |
| 2025-01-26 | 2026-03-25 | +4.3830 | -2.401 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 21:55:48.83 | -15:25:14.7 | HIP 108176 | 15.24 |
| 2026-03-26 12:00 | 21:57:29.95 | -15:17:06.2 | HIP 108414 | 10.58 |
| 2026-03-27 00:00 | 21:59:10.82 | -15:08:55.7 | HIP 108522 | 0.88 |
| 2026-03-27 12:00 | 22:00:51.44 | -15:00:43.3 | HIP 108522 | 26.33 |
| 2026-03-28 00:00 | 22:02:31.82 | -14:52:28.9 | HIP 108882 | 13.21 |
| 2026-03-28 12:00 | 22:04:11.96 | -14:44:12.7 | HIP 108882 | 17.49 |
| 2026-03-29 00:00 | 22:05:51.84 | -14:35:54.6 | HIP 109122 | 18.57 |
| 2026-03-29 12:00 | 22:07:31.48 | -14:27:34.8 | HIP 109220 | 2.07 |
| 2026-03-30 00:00 | 22:09:10.88 | -14:19:13.2 | HIP 109392 | 16.43 |
| 2026-03-30 12:00 | 22:10:50.02 | -14:10:50.0 | HIP 109607 | 20.02 |
| 2026-03-31 00:00 | 22:12:28.91 | -14:02:25.1 | HIP 109624 | 9.24 |
| 2026-03-31 12:00 | 22:14:07.56 | -13:53:58.6 | HIP 109683 | 14.98 |
| 2026-04-01 00:00 | 22:15:45.95 | -13:45:30.6 | HIP 109970 | 19.65 |
| 2026-04-01 12:00 | 22:17:24.10 | -13:37:01.1 | HIP 109970 | 29.39 |
| 2026-04-02 00:00 | 22:19:01.99 | -13:28:30.2 | HIP 110179 | 10.21 |
| 2026-04-02 12:00 | 22:20:39.63 | -13:19:57.8 | HIP 110179 | 24.13 |
| 2026-04-03 00:00 | 22:22:17.02 | -13:11:24.1 | HIP 110611 | 33.11 |
| 2026-04-03 12:00 | 22:23:54.16 | -13:02:49.1 | HIP 110611 | 12.57 |
| 2026-04-04 00:00 | 22:25:31.05 | -12:54:12.9 | HIP 110741 | 11.03 |
| 2026-04-04 12:00 | 22:27:07.69 | -12:45:35.4 | HIP 110741 | 14.63 |
| 2026-04-05 00:00 | 22:28:44.07 | -12:36:56.8 | HIP 111066 | 26.04 |
| 2026-04-05 12:00 | 22:30:20.20 | -12:28:17.1 | HIP 111066 | 27.01 |
| 2026-04-06 00:00 | 22:31:56.08 | -12:19:36.3 | HIP 111376 | 27.72 |
| 2026-04-06 12:00 | 22:33:31.70 | -12:10:54.5 | HIP 111396 | 8.16 |
| 2026-04-07 00:00 | 22:35:07.07 | -12:02:11.7 | HIP 111396 | 16.93 |
| 2026-04-07 12:00 | 22:36:42.19 | -11:53:28.0 | HIP 111652 | 11.27 |
| 2026-04-08 00:00 | 22:38:17.05 | -11:44:43.4 | HIP 111652 | 17.34 |
| 2026-04-08 12:00 | 22:39:51.66 | -11:35:58.0 | HIP 111930 | 7.13 |
| 2026-04-09 00:00 | 22:41:26.01 | -11:27:11.7 | HIP 111930 | 18.41 |
| 2026-04-09 12:00 | 22:43:00.11 | -11:18:24.8 | HIP 112232 | 16.31 |
| 2026-04-10 00:00 | 22:44:33.95 | -11:09:37.1 | HIP 112232 | 22.08 |
| 2026-04-10 12:00 | 22:46:07.54 | -11:00:48.8 | HIP 112420 | 9.31 |
| 2026-04-11 00:00 | 22:47:40.88 | -10:52:00.0 | HIP 112615 | 22.25 |
| 2026-04-11 12:00 | 22:49:13.96 | -10:43:10.4 | HIP 112615 | 14.58 |
| 2026-04-12 00:00 | 22:50:46.78 | -10:34:20.4 | HIP 112757 | 13.91 |
| 2026-04-12 12:00 | 22:52:19.35 | -10:25:30.0 | HIP 112974 | 22.95 |
| 2026-04-13 00:00 | 22:53:51.67 | -10:16:39.1 | HIP 113123 | 9.53 |
| 2026-04-13 12:00 | 22:55:23.72 | -10:07:47.8 | HIP 113199 | 1.22 |
| 2026-04-14 00:00 | 22:56:55.53 | -09:58:56.2 | HIP 113310 | 16.91 |
| 2026-04-14 12:00 | 22:58:27.07 | -09:50:04.4 | HIP 113310 | 35.20 |
| 2026-04-15 00:00 | 22:59:58.36 | -09:41:12.2 | HIP 113658 | 18.90 |
| 2026-04-15 12:00 | 23:01:29.40 | -09:32:19.9 | HIP 113658 | 5.38 |
| 2026-04-16 00:00 | 23:03:00.17 | -09:23:27.4 | HIP 113828 | 10.86 |