| Parameter |
Value |
| Designation |
C/1987 B1 (Nishikawa-Takamizawa-Tago) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-03-17T08:17:23.208000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
87 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
5.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1987-02-26.0000000 |
| e |
0.99579827 |
| q (au) |
0.869588 |
| a (au) |
206.959563 |
| i (deg) |
172.229985 |
| Ω (om, deg) |
176.010516 |
| ω (w, deg) |
200.401841 |
| M (ma, deg) |
359.993596 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.240 + 4.361\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.240 |
| n |
4.361 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.996 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
11:15:01.91 |
+05:59:09.8 |
HIP 54904 |
7.31 |
| 2026-06-01 12:00 |
11:15:01.64 |
+05:59:11.1 |
HIP 54904 |
7.24 |
| 2026-06-02 00:00 |
11:15:01.38 |
+05:59:12.2 |
HIP 54904 |
7.18 |
| 2026-06-02 12:00 |
11:15:01.14 |
+05:59:13.2 |
HIP 54904 |
7.11 |
| 2026-06-03 00:00 |
11:15:00.92 |
+05:59:14.2 |
HIP 54904 |
7.06 |
| 2026-06-03 12:00 |
11:15:00.71 |
+05:59:15.1 |
HIP 54904 |
7.00 |
| 2026-06-04 00:00 |
11:15:00.51 |
+05:59:15.8 |
HIP 54904 |
6.96 |
| 2026-06-04 12:00 |
11:15:00.33 |
+05:59:16.5 |
HIP 54904 |
6.91 |
| 2026-06-05 00:00 |
11:15:00.16 |
+05:59:17.1 |
HIP 54904 |
6.87 |
| 2026-06-05 12:00 |
11:15:00.01 |
+05:59:17.5 |
HIP 54904 |
6.83 |
| 2026-06-06 00:00 |
11:14:59.87 |
+05:59:17.9 |
HIP 54904 |
6.80 |
| 2026-06-06 12:00 |
11:14:59.75 |
+05:59:18.2 |
HIP 54904 |
6.76 |
| 2026-06-07 00:00 |
11:14:59.64 |
+05:59:18.4 |
HIP 54904 |
6.74 |
| 2026-06-07 12:00 |
11:14:59.55 |
+05:59:18.5 |
HIP 54904 |
6.71 |
| 2026-06-08 00:00 |
11:14:59.47 |
+05:59:18.6 |
HIP 54904 |
6.69 |
| 2026-06-08 12:00 |
11:14:59.41 |
+05:59:18.5 |
HIP 54904 |
6.68 |
| 2026-06-09 00:00 |
11:14:59.36 |
+05:59:18.3 |
HIP 54904 |
6.67 |
| 2026-06-09 12:00 |
11:14:59.32 |
+05:59:18.0 |
HIP 54904 |
6.66 |
| 2026-06-10 00:00 |
11:14:59.31 |
+05:59:17.7 |
HIP 54904 |
6.65 |
| 2026-06-10 12:00 |
11:14:59.30 |
+05:59:17.2 |
HIP 54904 |
6.65 |
| 2026-06-11 00:00 |
11:14:59.31 |
+05:59:16.7 |
HIP 54904 |
6.66 |
| 2026-06-11 12:00 |
11:14:59.34 |
+05:59:16.0 |
HIP 54904 |
6.66 |
| 2026-06-12 00:00 |
11:14:59.38 |
+05:59:15.3 |
HIP 54904 |
6.67 |
| 2026-06-12 12:00 |
11:14:59.43 |
+05:59:14.5 |
HIP 54904 |
6.69 |
| 2026-06-13 00:00 |
11:14:59.50 |
+05:59:13.6 |
HIP 54904 |
6.71 |
| 2026-06-13 12:00 |
11:14:59.59 |
+05:59:12.6 |
HIP 54904 |
6.73 |
| 2026-06-14 00:00 |
11:14:59.69 |
+05:59:11.5 |
HIP 54904 |
6.75 |
| 2026-06-14 12:00 |
11:14:59.80 |
+05:59:10.3 |
HIP 54904 |
6.78 |
| 2026-06-15 00:00 |
11:14:59.93 |
+05:59:09.0 |
HIP 54904 |
6.82 |
| 2026-06-15 12:00 |
11:15:00.07 |
+05:59:07.6 |
HIP 54904 |
6.85 |
| 2026-06-16 00:00 |
11:15:00.23 |
+05:59:06.1 |
HIP 54904 |
6.89 |
| 2026-06-16 12:00 |
11:15:00.40 |
+05:59:04.6 |
HIP 54904 |
6.94 |
| 2026-06-17 00:00 |
11:15:00.59 |
+05:59:02.9 |
HIP 54904 |
6.99 |
| 2026-06-17 12:00 |
11:15:00.79 |
+05:59:01.1 |
HIP 54904 |
7.04 |
| 2026-06-18 00:00 |
11:15:01.01 |
+05:58:59.3 |
HIP 54904 |
7.10 |
| 2026-06-18 12:00 |
11:15:01.24 |
+05:58:57.4 |
HIP 54904 |
7.16 |
| 2026-06-19 00:00 |
11:15:01.49 |
+05:58:55.4 |
HIP 54904 |
7.22 |
| 2026-06-19 12:00 |
11:15:01.75 |
+05:58:53.2 |
HIP 54904 |
7.29 |
| 2026-06-20 00:00 |
11:15:02.02 |
+05:58:51.0 |
HIP 54904 |
7.36 |
| 2026-06-20 12:00 |
11:15:02.31 |
+05:58:48.7 |
HIP 54904 |
7.43 |
| 2026-06-21 00:00 |
11:15:02.61 |
+05:58:46.4 |
HIP 54904 |
7.51 |
| 2026-06-21 12:00 |
11:15:02.93 |
+05:58:43.9 |
HIP 54904 |
7.60 |
| 2026-06-22 00:00 |
11:15:03.26 |
+05:58:41.3 |
HIP 54904 |
7.68 |