C/1996 B2 (Hyakutake)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1996 B2 (Hyakutake) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1996-05-01T09:27:34.128000Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:47Z |
| Obs used | 977 |
| NEO | - |
| M1 | 7.400 |
| K1 | 10.750 |
| PC | 0.030 |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 1996-03-15.0000000 |
| e | 0.99989165 |
| q (au) | 0.230224 |
| a (au) | 2124.755444 |
| i (deg) | 124.922049 |
| Ω (om, deg) | 188.045132 |
| ω (w, deg) | 130.175121 |
| M (ma, deg) | 359.999523 |
Magnitude
Scatter + Global Linear
$$ M_a = (5.511 + 2.906\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 5.511 |
| n | 2.906 |
| gf | 0.800 |
| gb | -0.500 |
| k | 0.874 |
| δ90 | 1.000 |
| 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 |
|---|---|---|---|
| 1996-01-01 | 1996-02-19 | +29.8235 | -6.481 |
| 1996-02-19 | 1996-03-29 | +2.2342 | -0.120 |
| 1996-03-29 | 1996-05-01 | -0.2001 | +0.012 |
| 1996-05-01 | 1996-05-17 | +4.8585 | +1.527 |
| 1996-05-17 | 1996-06-11 | -2.2356 | -0.537 |
| 1996-06-11 | 1996-07-06 | +3.6146 | -0.826 |
| 1996-07-06 | 1996-08-01 | +3.0246 | -0.925 |
| 1996-08-01 | 1996-10-24 | +15.0784 | -4.852 |
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 | 13:40:44.81 | -58:52:27.1 | HIP 66849 | 11.17 |
| 2026-06-01 12:00 | 13:40:41.90 | -58:52:04.3 | HIP 66849 | 11.34 |
| 2026-06-02 00:00 | 13:40:39.02 | -58:51:41.3 | HIP 66849 | 11.53 |
| 2026-06-02 12:00 | 13:40:36.16 | -58:51:18.2 | HIP 66849 | 11.73 |
| 2026-06-03 00:00 | 13:40:33.33 | -58:50:55.1 | HIP 66849 | 11.95 |
| 2026-06-03 12:00 | 13:40:30.52 | -58:50:31.8 | HIP 66849 | 12.19 |
| 2026-06-04 00:00 | 13:40:27.73 | -58:50:08.4 | HIP 66849 | 12.44 |
| 2026-06-04 12:00 | 13:40:24.97 | -58:49:45.0 | HIP 66849 | 12.70 |
| 2026-06-05 00:00 | 13:40:22.24 | -58:49:21.4 | HIP 66849 | 12.98 |
| 2026-06-05 12:00 | 13:40:19.53 | -58:48:57.7 | HIP 66849 | 13.27 |
| 2026-06-06 00:00 | 13:40:16.85 | -58:48:34.0 | HIP 66849 | 13.57 |
| 2026-06-06 12:00 | 13:40:14.20 | -58:48:10.2 | HIP 66849 | 13.88 |
| 2026-06-07 00:00 | 13:40:11.57 | -58:47:46.2 | HIP 66605 | 13.43 |
| 2026-06-07 12:00 | 13:40:08.96 | -58:47:22.2 | HIP 66605 | 12.91 |
| 2026-06-08 00:00 | 13:40:06.39 | -58:46:58.1 | HIP 66605 | 12.39 |
| 2026-06-08 12:00 | 13:40:03.84 | -58:46:33.9 | HIP 66605 | 11.87 |
| 2026-06-09 00:00 | 13:40:01.31 | -58:46:09.7 | HIP 66605 | 11.35 |
| 2026-06-09 12:00 | 13:39:58.82 | -58:45:45.3 | HIP 66605 | 10.83 |
| 2026-06-10 00:00 | 13:39:56.35 | -58:45:20.9 | HIP 66605 | 10.32 |
| 2026-06-10 12:00 | 13:39:53.91 | -58:44:56.4 | HIP 66605 | 9.80 |
| 2026-06-11 00:00 | 13:39:51.50 | -58:44:31.9 | HIP 66605 | 9.28 |
| 2026-06-11 12:00 | 13:39:49.11 | -58:44:07.2 | HIP 66605 | 8.77 |
| 2026-06-12 00:00 | 13:39:46.75 | -58:43:42.5 | HIP 66605 | 8.26 |
| 2026-06-12 12:00 | 13:39:44.42 | -58:43:17.7 | HIP 66605 | 7.75 |
| 2026-06-13 00:00 | 13:39:42.12 | -58:42:52.9 | HIP 66605 | 7.24 |
| 2026-06-13 12:00 | 13:39:39.85 | -58:42:28.0 | HIP 66605 | 6.73 |
| 2026-06-14 00:00 | 13:39:37.61 | -58:42:03.0 | HIP 66605 | 6.22 |
| 2026-06-14 12:00 | 13:39:35.39 | -58:41:38.0 | HIP 66605 | 5.71 |
| 2026-06-15 00:00 | 13:39:33.21 | -58:41:12.9 | HIP 66605 | 5.21 |
| 2026-06-15 12:00 | 13:39:31.05 | -58:40:47.7 | HIP 66605 | 4.70 |
| 2026-06-16 00:00 | 13:39:28.92 | -58:40:22.5 | HIP 66605 | 4.20 |
| 2026-06-16 12:00 | 13:39:26.82 | -58:39:57.3 | HIP 66605 | 3.70 |
| 2026-06-17 00:00 | 13:39:24.76 | -58:39:32.0 | HIP 66605 | 3.20 |
| 2026-06-17 12:00 | 13:39:22.72 | -58:39:06.6 | HIP 66605 | 2.70 |
| 2026-06-18 00:00 | 13:39:20.71 | -58:38:41.2 | HIP 66605 | 2.20 |
| 2026-06-18 12:00 | 13:39:18.73 | -58:38:15.8 | HIP 66605 | 1.71 |
| 2026-06-19 00:00 | 13:39:16.78 | -58:37:50.3 | HIP 66605 | 1.22 |
| 2026-06-19 12:00 | 13:39:14.86 | -58:37:24.8 | HIP 66605 | 0.73 |
| 2026-06-20 00:00 | 13:39:12.97 | -58:36:59.3 | HIP 66605 | 0.26 |
| 2026-06-20 12:00 | 13:39:11.12 | -58:36:33.7 | HIP 66605 | 0.30 |
| 2026-06-21 00:00 | 13:39:09.29 | -58:36:08.1 | HIP 66605 | 0.77 |
| 2026-06-21 12:00 | 13:39:07.49 | -58:35:42.4 | HIP 66605 | 1.25 |
| 2026-06-22 00:00 | 13:39:05.72 | -58:35:16.7 | HIP 66605 | 1.74 |