| 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) |
| 2026-05-12 00:00 |
11:15:24.66 |
+05:57:04.3 |
HIP 54904 |
13.19 |
| 2026-05-12 12:00 |
11:15:23.81 |
+05:57:09.2 |
HIP 54904 |
12.97 |
| 2026-05-13 00:00 |
11:15:22.98 |
+05:57:14.1 |
HIP 54904 |
12.75 |
| 2026-05-13 12:00 |
11:15:22.16 |
+05:57:18.8 |
HIP 54904 |
12.54 |
| 2026-05-14 00:00 |
11:15:21.36 |
+05:57:23.5 |
HIP 54904 |
12.33 |
| 2026-05-14 12:00 |
11:15:20.56 |
+05:57:28.1 |
HIP 54904 |
12.12 |
| 2026-05-15 00:00 |
11:15:19.79 |
+05:57:32.5 |
HIP 54904 |
11.92 |
| 2026-05-15 12:00 |
11:15:19.02 |
+05:57:36.9 |
HIP 54904 |
11.72 |
| 2026-05-16 00:00 |
11:15:18.28 |
+05:57:41.2 |
HIP 54904 |
11.52 |
| 2026-05-16 12:00 |
11:15:17.54 |
+05:57:45.4 |
HIP 54904 |
11.33 |
| 2026-05-17 00:00 |
11:15:16.82 |
+05:57:49.5 |
HIP 54904 |
11.14 |
| 2026-05-17 12:00 |
11:15:16.11 |
+05:57:53.6 |
HIP 54904 |
10.96 |
| 2026-05-18 00:00 |
11:15:15.42 |
+05:57:57.5 |
HIP 54904 |
10.78 |
| 2026-05-18 12:00 |
11:15:14.74 |
+05:58:01.3 |
HIP 54904 |
10.60 |
| 2026-05-19 00:00 |
11:15:14.08 |
+05:58:05.1 |
HIP 54904 |
10.43 |
| 2026-05-19 12:00 |
11:15:13.43 |
+05:58:08.7 |
HIP 54904 |
10.26 |
| 2026-05-20 00:00 |
11:15:12.79 |
+05:58:12.3 |
HIP 54904 |
10.09 |
| 2026-05-20 12:00 |
11:15:12.17 |
+05:58:15.8 |
HIP 54904 |
9.93 |
| 2026-05-21 00:00 |
11:15:11.56 |
+05:58:19.1 |
HIP 54904 |
9.78 |
| 2026-05-21 12:00 |
11:15:10.97 |
+05:58:22.4 |
HIP 54904 |
9.62 |
| 2026-05-22 00:00 |
11:15:10.40 |
+05:58:25.6 |
HIP 54904 |
9.48 |
| 2026-05-22 12:00 |
11:15:09.83 |
+05:58:28.7 |
HIP 54904 |
9.33 |
| 2026-05-23 00:00 |
11:15:09.28 |
+05:58:31.7 |
HIP 54904 |
9.19 |
| 2026-05-23 12:00 |
11:15:08.75 |
+05:58:34.6 |
HIP 54904 |
9.05 |
| 2026-05-24 00:00 |
11:15:08.23 |
+05:58:37.4 |
HIP 54904 |
8.92 |
| 2026-05-24 12:00 |
11:15:07.73 |
+05:58:40.2 |
HIP 54904 |
8.79 |
| 2026-05-25 00:00 |
11:15:07.24 |
+05:58:42.8 |
HIP 54904 |
8.66 |
| 2026-05-25 12:00 |
11:15:06.76 |
+05:58:45.3 |
HIP 54904 |
8.54 |
| 2026-05-26 00:00 |
11:15:06.30 |
+05:58:47.8 |
HIP 54904 |
8.42 |
| 2026-05-26 12:00 |
11:15:05.85 |
+05:58:50.1 |
HIP 54904 |
8.31 |
| 2026-05-27 00:00 |
11:15:05.42 |
+05:58:52.4 |
HIP 54904 |
8.20 |
| 2026-05-27 12:00 |
11:15:05.00 |
+05:58:54.6 |
HIP 54904 |
8.09 |
| 2026-05-28 00:00 |
11:15:04.60 |
+05:58:56.6 |
HIP 54904 |
7.99 |
| 2026-05-28 12:00 |
11:15:04.21 |
+05:58:58.6 |
HIP 54904 |
7.89 |
| 2026-05-29 00:00 |
11:15:03.84 |
+05:59:00.5 |
HIP 54904 |
7.80 |
| 2026-05-29 12:00 |
11:15:03.48 |
+05:59:02.3 |
HIP 54904 |
7.71 |
| 2026-05-30 00:00 |
11:15:03.14 |
+05:59:04.0 |
HIP 54904 |
7.62 |
| 2026-05-30 12:00 |
11:15:02.81 |
+05:59:05.6 |
HIP 54904 |
7.53 |
| 2026-05-31 00:00 |
11:15:02.49 |
+05:59:07.1 |
HIP 54904 |
7.46 |
| 2026-05-31 12:00 |
11:15:02.19 |
+05:59:08.5 |
HIP 54904 |
7.38 |
| 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 |