C/1995 O1 (Hale-Bopp)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1995 O1 (Hale-Bopp) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1997-03-29T15:14:15.973440Z |
| Orbit solution date (soln_date, UTC) | 2022-08-01T01:56:46Z |
| Obs used | 66 |
| NEO | - |
| M1 | 4.800 |
| K1 | 4.000 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2022-09-15.0000000 |
| e | 0.99498100 |
| q (au) | 0.890538 |
| a (au) | 177.433384 |
| i (deg) | 89.287594 |
| Ω (om, deg) | 282.733421 |
| ω (w, deg) | 130.414667 |
| M (ma, deg) | 3.878386 |
Magnitude
Scatter + Global Linear
$$ M_a = (-1.380 + 3.909\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | -1.380 |
| n | 3.909 |
| gf | 1.000 |
| gb | -0.775 |
| k | 0.992 |
| 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 |
|---|---|---|---|
| 1993-04-27 | 1995-08-14 | +22.3833 | -18.478 |
| 1995-08-14 | 1996-10-19 | +1.1208 | -0.683 |
| 1996-10-19 | 1996-11-12 | -13.5265 | +5.695 |
| 1996-11-12 | 1997-03-29 | +1.5785 | +0.131 |
| 1997-03-29 | 1997-10-13 | +1.1436 | -0.117 |
| 1997-10-13 | 2000-02-10 | -1.1481 | +1.410 |
| 2000-02-10 | 2013-08-13 | +6.3115 | -6.332 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 22:37:45.25 | -85:21:22.7 | HIP 112146 | 11.11 |
| 2026-07-29 12:00 | 22:37:22.02 | -85:21:42.2 | HIP 112146 | 11.11 |
| 2026-07-30 00:00 | 22:36:58.63 | -85:22:01.5 | HIP 112146 | 11.14 |
| 2026-07-30 12:00 | 22:36:35.08 | -85:22:20.4 | HIP 112146 | 11.21 |
| 2026-07-31 00:00 | 22:36:11.36 | -85:22:39.1 | HIP 112146 | 11.31 |
| 2026-07-31 12:00 | 22:35:47.48 | -85:22:57.5 | HIP 112146 | 11.44 |
| 2026-08-01 00:00 | 22:35:23.43 | -85:23:15.6 | HIP 112146 | 11.60 |
| 2026-08-01 12:00 | 22:34:59.24 | -85:23:33.4 | HIP 112146 | 11.79 |
| 2026-08-02 00:00 | 22:34:34.88 | -85:23:51.0 | HIP 112146 | 12.01 |
| 2026-08-02 12:00 | 22:34:10.38 | -85:24:08.2 | HIP 112146 | 12.26 |
| 2026-08-03 00:00 | 22:33:45.72 | -85:24:25.1 | HIP 112146 | 12.53 |
| 2026-08-03 12:00 | 22:33:20.92 | -85:24:41.8 | HIP 112146 | 12.83 |
| 2026-08-04 00:00 | 22:32:55.97 | -85:24:58.1 | HIP 112146 | 13.14 |
| 2026-08-04 12:00 | 22:32:30.88 | -85:25:14.2 | HIP 112146 | 13.48 |
| 2026-08-05 00:00 | 22:32:05.64 | -85:25:29.9 | HIP 112146 | 13.83 |
| 2026-08-05 12:00 | 22:31:40.27 | -85:25:45.3 | HIP 112146 | 14.20 |
| 2026-08-06 00:00 | 22:31:14.76 | -85:26:00.5 | HIP 112146 | 14.59 |
| 2026-08-06 12:00 | 22:30:49.13 | -85:26:15.3 | HIP 112146 | 14.99 |
| 2026-08-07 00:00 | 22:30:23.36 | -85:26:29.8 | HIP 112146 | 15.41 |
| 2026-08-07 12:00 | 22:29:57.46 | -85:26:44.0 | HIP 112146 | 15.83 |
| 2026-08-08 00:00 | 22:29:31.44 | -85:26:57.8 | HIP 112146 | 16.27 |
| 2026-08-08 12:00 | 22:29:05.30 | -85:27:11.4 | HIP 112146 | 16.72 |
| 2026-08-09 00:00 | 22:28:39.04 | -85:27:24.6 | HIP 112146 | 17.18 |
| 2026-08-09 12:00 | 22:28:12.67 | -85:27:37.5 | HIP 112146 | 17.64 |
| 2026-08-10 00:00 | 22:27:46.18 | -85:27:50.1 | HIP 112146 | 18.12 |
| 2026-08-10 12:00 | 22:27:19.59 | -85:28:02.4 | HIP 112146 | 18.60 |
| 2026-08-11 00:00 | 22:26:52.89 | -85:28:14.3 | HIP 112146 | 19.09 |
| 2026-08-11 12:00 | 22:26:26.08 | -85:28:25.9 | HIP 112146 | 19.58 |
| 2026-08-12 00:00 | 22:25:59.18 | -85:28:37.2 | HIP 112146 | 20.08 |
| 2026-08-12 12:00 | 22:25:32.18 | -85:28:48.1 | HIP 112146 | 20.58 |
| 2026-08-13 00:00 | 22:25:05.09 | -85:28:58.7 | HIP 112146 | 21.09 |
| 2026-08-13 12:00 | 22:24:37.91 | -85:29:09.0 | HIP 112146 | 21.60 |
| 2026-08-14 00:00 | 22:24:10.65 | -85:29:19.0 | HIP 112146 | 22.12 |
| 2026-08-14 12:00 | 22:23:43.31 | -85:29:28.6 | HIP 112146 | 22.64 |
| 2026-08-15 00:00 | 22:23:15.88 | -85:29:37.8 | HIP 112146 | 23.16 |
| 2026-08-15 12:00 | 22:22:48.39 | -85:29:46.7 | HIP 112146 | 23.69 |
| 2026-08-16 00:00 | 22:22:20.82 | -85:29:55.3 | HIP 112146 | 24.22 |
| 2026-08-16 12:00 | 22:21:53.18 | -85:30:03.6 | HIP 112146 | 24.75 |
| 2026-08-17 00:00 | 22:21:25.48 | -85:30:11.5 | HIP 112146 | 25.28 |
| 2026-08-17 12:00 | 22:20:57.72 | -85:30:19.0 | HIP 112146 | 25.82 |
| 2026-08-18 00:00 | 22:20:29.91 | -85:30:26.2 | HIP 112146 | 26.35 |
| 2026-08-18 12:00 | 22:20:02.04 | -85:30:33.1 | HIP 112146 | 26.89 |
| 2026-08-19 00:00 | 22:19:34.12 | -85:30:39.6 | HIP 112146 | 27.43 |