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 | +29.8208 | -6.480 |
| 1996-02-19 | 1996-03-29 | +2.2342 | -0.120 |
| 1996-03-29 | 1996-05-01 | -0.1997 | +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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 13:49:10.12 | -59:17:43.0 | HIP 67552 | 11.21 |
| 2026-03-26 12:00 | 13:49:06.40 | -59:17:45.9 | HIP 67552 | 11.63 |
| 2026-03-27 00:00 | 13:49:02.66 | -59:17:48.5 | HIP 67552 | 12.06 |
| 2026-03-27 12:00 | 13:48:58.91 | -59:17:51.0 | HIP 67552 | 12.50 |
| 2026-03-28 00:00 | 13:48:55.14 | -59:17:53.1 | HIP 67552 | 12.94 |
| 2026-03-28 12:00 | 13:48:51.36 | -59:17:55.1 | HIP 67552 | 13.39 |
| 2026-03-29 00:00 | 13:48:47.57 | -59:17:56.8 | HIP 67552 | 13.84 |
| 2026-03-29 12:00 | 13:48:43.76 | -59:17:58.3 | HIP 67552 | 14.30 |
| 2026-03-30 00:00 | 13:48:39.95 | -59:17:59.6 | HIP 67552 | 14.76 |
| 2026-03-30 12:00 | 13:48:36.11 | -59:18:00.6 | HIP 67552 | 15.22 |
| 2026-03-31 00:00 | 13:48:32.27 | -59:18:01.4 | HIP 67552 | 15.69 |
| 2026-03-31 12:00 | 13:48:28.42 | -59:18:02.0 | HIP 67552 | 16.17 |
| 2026-04-01 00:00 | 13:48:24.55 | -59:18:02.3 | HIP 67552 | 16.64 |
| 2026-04-01 12:00 | 13:48:20.67 | -59:18:02.5 | HIP 67552 | 17.12 |
| 2026-04-02 00:00 | 13:48:16.78 | -59:18:02.3 | HIP 67552 | 17.61 |
| 2026-04-02 12:00 | 13:48:12.88 | -59:18:02.0 | HIP 67552 | 18.09 |
| 2026-04-03 00:00 | 13:48:08.98 | -59:18:01.4 | HIP 67552 | 18.58 |
| 2026-04-03 12:00 | 13:48:05.06 | -59:18:00.6 | HIP 67552 | 19.07 |
| 2026-04-04 00:00 | 13:48:01.13 | -59:17:59.6 | HIP 67552 | 19.57 |
| 2026-04-04 12:00 | 13:47:57.19 | -59:17:58.3 | HIP 67552 | 20.06 |
| 2026-04-05 00:00 | 13:47:53.24 | -59:17:56.8 | HIP 67552 | 20.56 |
| 2026-04-05 12:00 | 13:47:49.28 | -59:17:55.1 | HIP 67552 | 21.06 |
| 2026-04-06 00:00 | 13:47:45.32 | -59:17:53.1 | HIP 67552 | 21.57 |
| 2026-04-06 12:00 | 13:47:41.34 | -59:17:50.9 | HIP 67552 | 22.07 |
| 2026-04-07 00:00 | 13:47:37.36 | -59:17:48.5 | HIP 67552 | 22.58 |
| 2026-04-07 12:00 | 13:47:33.37 | -59:17:45.9 | HIP 67552 | 23.08 |
| 2026-04-08 00:00 | 13:47:29.38 | -59:17:43.0 | HIP 67552 | 23.59 |
| 2026-04-08 12:00 | 13:47:25.38 | -59:17:39.9 | HIP 67552 | 24.11 |
| 2026-04-09 00:00 | 13:47:21.37 | -59:17:36.5 | HIP 67552 | 24.62 |
| 2026-04-09 12:00 | 13:47:17.35 | -59:17:33.0 | HIP 67552 | 25.13 |
| 2026-04-10 00:00 | 13:47:13.33 | -59:17:29.2 | HIP 67014 | 24.71 |
| 2026-04-10 12:00 | 13:47:09.30 | -59:17:25.1 | HIP 67014 | 24.19 |
| 2026-04-11 00:00 | 13:47:05.27 | -59:17:20.9 | HIP 67014 | 23.67 |
| 2026-04-11 12:00 | 13:47:01.23 | -59:17:16.4 | HIP 67014 | 23.15 |
| 2026-04-12 00:00 | 13:46:57.19 | -59:17:11.7 | HIP 67014 | 22.63 |
| 2026-04-12 12:00 | 13:46:53.14 | -59:17:06.7 | HIP 67014 | 22.10 |
| 2026-04-13 00:00 | 13:46:49.09 | -59:17:01.6 | HIP 67014 | 21.58 |
| 2026-04-13 12:00 | 13:46:45.03 | -59:16:56.2 | HIP 67014 | 21.06 |
| 2026-04-14 00:00 | 13:46:40.98 | -59:16:50.5 | HIP 67014 | 20.53 |
| 2026-04-14 12:00 | 13:46:36.92 | -59:16:44.7 | HIP 67014 | 20.00 |
| 2026-04-15 00:00 | 13:46:32.85 | -59:16:38.6 | HIP 67014 | 19.48 |
| 2026-04-15 12:00 | 13:46:28.79 | -59:16:32.3 | HIP 67014 | 18.95 |
| 2026-04-16 00:00 | 13:46:24.72 | -59:16:25.7 | HIP 67014 | 18.42 |