| Parameter |
Value |
| Designation |
C/1987 B2 (Terasako) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1986-12-24T21:01:50.280960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
49 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1987-02-07.0000000 |
| e |
0.99522002 |
| q (au) |
0.392887 |
| a (au) |
82.194165 |
| i (deg) |
40.856893 |
| Ω (om, deg) |
97.699267 |
| ω (w, deg) |
195.270339 |
| M (ma, deg) |
0.058360 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.591 + 3.937\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.591 |
| n |
3.937 |
| gf |
0.983 |
| gb |
-1.000 |
| k |
0.962 |
| δ90 |
9.860 |
| 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) |
| 2026-07-29 00:00 |
07:03:14.95 |
+27:46:02.1 |
HIP 33915 |
12.69 |
| 2026-07-29 12:00 |
07:03:17.00 |
+27:46:00.4 |
HIP 33915 |
13.14 |
| 2026-07-30 00:00 |
07:03:19.05 |
+27:45:58.7 |
HIP 33915 |
13.59 |
| 2026-07-30 12:00 |
07:03:21.10 |
+27:45:57.1 |
HIP 33915 |
14.04 |
| 2026-07-31 00:00 |
07:03:23.13 |
+27:45:55.4 |
HIP 33915 |
14.49 |
| 2026-07-31 12:00 |
07:03:25.16 |
+27:45:53.8 |
HIP 33915 |
14.94 |
| 2026-08-01 00:00 |
07:03:27.19 |
+27:45:52.3 |
HIP 33915 |
15.38 |
| 2026-08-01 12:00 |
07:03:29.20 |
+27:45:50.7 |
HIP 33915 |
15.83 |
| 2026-08-02 00:00 |
07:03:31.21 |
+27:45:49.2 |
HIP 33915 |
16.27 |
| 2026-08-02 12:00 |
07:03:33.21 |
+27:45:47.7 |
HIP 33915 |
16.71 |
| 2026-08-03 00:00 |
07:03:35.20 |
+27:45:46.3 |
HIP 33915 |
17.15 |
| 2026-08-03 12:00 |
07:03:37.19 |
+27:45:44.9 |
HIP 33915 |
17.59 |
| 2026-08-04 00:00 |
07:03:39.16 |
+27:45:43.5 |
HIP 33915 |
18.02 |
| 2026-08-04 12:00 |
07:03:41.13 |
+27:45:42.1 |
HIP 33915 |
18.46 |
| 2026-08-05 00:00 |
07:03:43.09 |
+27:45:40.8 |
HIP 33915 |
18.89 |
| 2026-08-05 12:00 |
07:03:45.05 |
+27:45:39.5 |
HIP 33915 |
19.32 |
| 2026-08-06 00:00 |
07:03:46.99 |
+27:45:38.2 |
HIP 33915 |
19.75 |
| 2026-08-06 12:00 |
07:03:48.93 |
+27:45:37.0 |
HIP 33915 |
20.18 |
| 2026-08-07 00:00 |
07:03:50.85 |
+27:45:35.8 |
HIP 33915 |
20.60 |
| 2026-08-07 12:00 |
07:03:52.77 |
+27:45:34.6 |
HIP 33915 |
21.03 |
| 2026-08-08 00:00 |
07:03:54.68 |
+27:45:33.5 |
HIP 33915 |
21.45 |
| 2026-08-08 12:00 |
07:03:56.58 |
+27:45:32.3 |
HIP 33915 |
21.87 |
| 2026-08-09 00:00 |
07:03:58.47 |
+27:45:31.2 |
HIP 33915 |
22.29 |
| 2026-08-09 12:00 |
07:04:00.35 |
+27:45:30.2 |
HIP 33915 |
22.70 |
| 2026-08-10 00:00 |
07:04:02.22 |
+27:45:29.2 |
HIP 33915 |
23.12 |
| 2026-08-10 12:00 |
07:04:04.08 |
+27:45:28.2 |
HIP 33915 |
23.53 |
| 2026-08-11 00:00 |
07:04:05.93 |
+27:45:27.2 |
HIP 33915 |
23.94 |
| 2026-08-11 12:00 |
07:04:07.78 |
+27:45:26.3 |
HIP 33915 |
24.35 |
| 2026-08-12 00:00 |
07:04:09.61 |
+27:45:25.4 |
HIP 33915 |
24.75 |
| 2026-08-12 12:00 |
07:04:11.43 |
+27:45:24.5 |
HIP 33915 |
25.15 |
| 2026-08-13 00:00 |
07:04:13.24 |
+27:45:23.7 |
HIP 33915 |
25.55 |
| 2026-08-13 12:00 |
07:04:15.04 |
+27:45:22.9 |
HIP 34222 |
25.82 |
| 2026-08-14 00:00 |
07:04:16.83 |
+27:45:22.1 |
HIP 34222 |
25.51 |
| 2026-08-14 12:00 |
07:04:18.61 |
+27:45:21.4 |
HIP 34222 |
25.21 |
| 2026-08-15 00:00 |
07:04:20.38 |
+27:45:20.7 |
HIP 34222 |
24.92 |
| 2026-08-15 12:00 |
07:04:22.14 |
+27:45:20.0 |
HIP 34222 |
24.63 |
| 2026-08-16 00:00 |
07:04:23.88 |
+27:45:19.4 |
HIP 34222 |
24.34 |
| 2026-08-16 12:00 |
07:04:25.62 |
+27:45:18.8 |
HIP 34222 |
24.06 |
| 2026-08-17 00:00 |
07:04:27.34 |
+27:45:18.2 |
HIP 34222 |
23.79 |
| 2026-08-17 12:00 |
07:04:29.05 |
+27:45:17.7 |
HIP 34222 |
23.52 |
| 2026-08-18 00:00 |
07:04:30.75 |
+27:45:17.2 |
HIP 34222 |
23.26 |
| 2026-08-18 12:00 |
07:04:32.44 |
+27:45:16.7 |
HIP 34222 |
23.00 |
| 2026-08-19 00:00 |
07:04:34.11 |
+27:45:16.3 |
HIP 34222 |
22.74 |