C/1987 W2 (Furuyama)
| Parameter |
Value |
| Designation |
C/1987 W2 (Furuyama) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-03-03T01:38:49.009920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
152 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1988-01-12.0000000 |
| e |
1.00023007 |
| q (au) |
1.679522 |
| a (au) |
-7299.904944 |
| i (deg) |
117.781967 |
| Ω (om, deg) |
250.752559 |
| ω (w, deg) |
233.626815 |
| M (ma, deg) |
-0.000081 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.083 + 5.384\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.083 |
| n |
5.384 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
10.000 |
| 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) |
| 2026-02-03 00:00 |
15:55:29.56 |
+10:28:48.8 |
HIP 78055 |
15.15 |
| 2026-02-03 12:00 |
15:55:30.12 |
+10:29:02.3 |
HIP 78055 |
15.23 |
| 2026-02-04 00:00 |
15:55:30.65 |
+10:29:15.9 |
HIP 78055 |
15.30 |
| 2026-02-04 12:00 |
15:55:31.18 |
+10:29:29.6 |
HIP 78055 |
15.39 |
| 2026-02-05 00:00 |
15:55:31.68 |
+10:29:43.3 |
HIP 78055 |
15.48 |
| 2026-02-05 12:00 |
15:55:32.17 |
+10:29:57.1 |
HIP 78055 |
15.58 |
| 2026-02-06 00:00 |
15:55:32.65 |
+10:30:11.0 |
HIP 78055 |
15.69 |
| 2026-02-06 12:00 |
15:55:33.10 |
+10:30:25.0 |
HIP 78055 |
15.81 |
| 2026-02-07 00:00 |
15:55:33.55 |
+10:30:39.0 |
HIP 78055 |
15.93 |
| 2026-02-07 12:00 |
15:55:33.97 |
+10:30:53.1 |
HIP 78055 |
16.06 |
| 2026-02-08 00:00 |
15:55:34.38 |
+10:31:07.3 |
HIP 78055 |
16.19 |
| 2026-02-08 12:00 |
15:55:34.77 |
+10:31:21.6 |
HIP 78055 |
16.33 |
| 2026-02-09 00:00 |
15:55:35.15 |
+10:31:35.9 |
HIP 78055 |
16.48 |
| 2026-02-09 12:00 |
15:55:35.51 |
+10:31:50.4 |
HIP 78055 |
16.63 |
| 2026-02-10 00:00 |
15:55:35.85 |
+10:32:04.8 |
HIP 78055 |
16.79 |
| 2026-02-10 12:00 |
15:55:36.18 |
+10:32:19.4 |
HIP 78055 |
16.96 |
| 2026-02-11 00:00 |
15:55:36.49 |
+10:32:34.0 |
HIP 78055 |
17.13 |
| 2026-02-11 12:00 |
15:55:36.79 |
+10:32:48.7 |
HIP 78055 |
17.30 |
| 2026-02-12 00:00 |
15:55:37.06 |
+10:33:03.5 |
HIP 78055 |
17.48 |
| 2026-02-12 12:00 |
15:55:37.33 |
+10:33:18.3 |
HIP 78055 |
17.66 |
| 2026-02-13 00:00 |
15:55:37.57 |
+10:33:33.2 |
HIP 78055 |
17.85 |
| 2026-02-13 12:00 |
15:55:37.80 |
+10:33:48.2 |
HIP 78055 |
18.05 |
| 2026-02-14 00:00 |
15:55:38.01 |
+10:34:03.2 |
HIP 78055 |
18.25 |
| 2026-02-14 12:00 |
15:55:38.20 |
+10:34:18.3 |
HIP 78055 |
18.45 |
| 2026-02-15 00:00 |
15:55:38.38 |
+10:34:33.4 |
HIP 78055 |
18.65 |
| 2026-02-15 12:00 |
15:55:38.54 |
+10:34:48.6 |
HIP 78055 |
18.86 |
| 2026-02-16 00:00 |
15:55:38.69 |
+10:35:03.9 |
HIP 78055 |
19.08 |
| 2026-02-16 12:00 |
15:55:38.81 |
+10:35:19.2 |
HIP 78055 |
19.29 |
| 2026-02-17 00:00 |
15:55:38.92 |
+10:35:34.6 |
HIP 78055 |
19.52 |
| 2026-02-17 12:00 |
15:55:39.02 |
+10:35:50.0 |
HIP 78055 |
19.74 |
| 2026-02-18 00:00 |
15:55:39.10 |
+10:36:05.5 |
HIP 78055 |
19.97 |
| 2026-02-18 12:00 |
15:55:39.16 |
+10:36:21.0 |
HIP 78055 |
20.20 |
| 2026-02-19 00:00 |
15:55:39.20 |
+10:36:36.6 |
HIP 78055 |
20.43 |
| 2026-02-19 12:00 |
15:55:39.23 |
+10:36:52.3 |
HIP 78055 |
20.67 |
| 2026-02-20 00:00 |
15:55:39.24 |
+10:37:08.0 |
HIP 78055 |
20.91 |
| 2026-02-20 12:00 |
15:55:39.23 |
+10:37:23.7 |
HIP 78055 |
21.15 |
| 2026-02-21 00:00 |
15:55:39.20 |
+10:37:39.5 |
HIP 78055 |
21.40 |
| 2026-02-21 12:00 |
15:55:39.16 |
+10:37:55.3 |
HIP 78055 |
21.65 |
| 2026-02-22 00:00 |
15:55:39.10 |
+10:38:11.2 |
HIP 78029 |
21.50 |
| 2026-02-22 12:00 |
15:55:39.03 |
+10:38:27.1 |
HIP 78029 |
21.24 |
| 2026-02-23 00:00 |
15:55:38.94 |
+10:38:43.0 |
HIP 78029 |
20.99 |
| 2026-02-23 12:00 |
15:55:38.83 |
+10:38:59.0 |
HIP 78029 |
20.73 |
| 2026-02-24 00:00 |
15:55:38.71 |
+10:39:15.0 |
HIP 78029 |
20.48 |