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) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 22:59:20.14 | -84:24:04.7 | HIP 112859 | 14.45 |
| 2026-06-01 12:00 | 22:59:20.88 | -84:24:38.0 | HIP 112859 | 14.78 |
| 2026-06-02 00:00 | 22:59:21.43 | -84:25:11.3 | HIP 112859 | 15.12 |
| 2026-06-02 12:00 | 22:59:21.80 | -84:25:44.7 | HIP 112859 | 15.47 |
| 2026-06-03 00:00 | 22:59:21.99 | -84:26:18.1 | HIP 112859 | 15.83 |
| 2026-06-03 12:00 | 22:59:21.99 | -84:26:51.5 | HIP 112859 | 16.20 |
| 2026-06-04 00:00 | 22:59:21.81 | -84:27:25.0 | HIP 112859 | 16.57 |
| 2026-06-04 12:00 | 22:59:21.43 | -84:27:58.5 | HIP 112859 | 16.95 |
| 2026-06-05 00:00 | 22:59:20.87 | -84:28:32.0 | HIP 112859 | 17.34 |
| 2026-06-05 12:00 | 22:59:20.12 | -84:29:05.5 | HIP 112859 | 17.74 |
| 2026-06-06 00:00 | 22:59:19.18 | -84:29:39.1 | HIP 112859 | 18.14 |
| 2026-06-06 12:00 | 22:59:18.04 | -84:30:12.6 | HIP 112859 | 18.54 |
| 2026-06-07 00:00 | 22:59:16.71 | -84:30:46.2 | HIP 112859 | 18.96 |
| 2026-06-07 12:00 | 22:59:15.19 | -84:31:19.8 | HIP 112859 | 19.37 |
| 2026-06-08 00:00 | 22:59:13.48 | -84:31:53.5 | HIP 112859 | 19.79 |
| 2026-06-08 12:00 | 22:59:11.57 | -84:32:27.1 | HIP 112859 | 20.22 |
| 2026-06-09 00:00 | 22:59:09.46 | -84:33:00.7 | HIP 112859 | 20.65 |
| 2026-06-09 12:00 | 22:59:07.15 | -84:33:34.3 | HIP 112859 | 21.08 |
| 2026-06-10 00:00 | 22:59:04.65 | -84:34:08.0 | HIP 112859 | 21.52 |
| 2026-06-10 12:00 | 22:59:01.95 | -84:34:41.6 | HIP 112859 | 21.96 |
| 2026-06-11 00:00 | 22:58:59.04 | -84:35:15.2 | HIP 114306 | 22.28 |
| 2026-06-11 12:00 | 22:58:55.93 | -84:35:48.8 | HIP 114306 | 21.88 |
| 2026-06-12 00:00 | 22:58:52.63 | -84:36:22.4 | HIP 114306 | 21.49 |
| 2026-06-12 12:00 | 22:58:49.11 | -84:36:56.0 | HIP 114306 | 21.11 |
| 2026-06-13 00:00 | 22:58:45.40 | -84:37:29.6 | HIP 114306 | 20.74 |
| 2026-06-13 12:00 | 22:58:41.47 | -84:38:03.1 | HIP 114306 | 20.39 |
| 2026-06-14 00:00 | 22:58:37.35 | -84:38:36.7 | HIP 114306 | 20.04 |
| 2026-06-14 12:00 | 22:58:33.01 | -84:39:10.2 | HIP 114306 | 19.72 |
| 2026-06-15 00:00 | 22:58:28.47 | -84:39:43.6 | HIP 114306 | 19.40 |
| 2026-06-15 12:00 | 22:58:23.72 | -84:40:17.1 | HIP 114306 | 19.10 |
| 2026-06-16 00:00 | 22:58:18.76 | -84:40:50.5 | HIP 114306 | 18.82 |
| 2026-06-16 12:00 | 22:58:13.59 | -84:41:23.9 | HIP 114306 | 18.56 |
| 2026-06-17 00:00 | 22:58:08.21 | -84:41:57.2 | HIP 114306 | 18.31 |
| 2026-06-17 12:00 | 22:58:02.62 | -84:42:30.5 | HIP 114306 | 18.08 |
| 2026-06-18 00:00 | 22:57:56.81 | -84:43:03.7 | HIP 114306 | 17.87 |
| 2026-06-18 12:00 | 22:57:50.80 | -84:43:36.9 | HIP 114306 | 17.68 |
| 2026-06-19 00:00 | 22:57:44.57 | -84:44:10.1 | HIP 114306 | 17.51 |
| 2026-06-19 12:00 | 22:57:38.13 | -84:44:43.2 | HIP 114306 | 17.36 |
| 2026-06-20 00:00 | 22:57:31.48 | -84:45:16.2 | HIP 114306 | 17.24 |
| 2026-06-20 12:00 | 22:57:24.61 | -84:45:49.2 | HIP 114306 | 17.13 |
| 2026-06-21 00:00 | 22:57:17.52 | -84:46:22.1 | HIP 114306 | 17.05 |
| 2026-06-21 12:00 | 22:57:10.23 | -84:46:54.9 | HIP 114306 | 16.99 |
| 2026-06-22 00:00 | 22:57:02.71 | -84:47:27.7 | HIP 114306 | 16.96 |