| Parameter |
Value |
| Designation |
C/1989 A1 (Yanaka) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-10-31T19:17:00.879360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
101 |
| NEO |
- |
| M1 |
5.700 |
| K1 |
16.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1989-02-04.0000000 |
| e |
0.99863759 |
| q (au) |
1.894621 |
| a (au) |
1390.639657 |
| i (deg) |
52.409723 |
| Ω (om, deg) |
157.088675 |
| ω (w, deg) |
351.561502 |
| M (ma, deg) |
0.001809 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.241 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.241 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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) |
| 2026-07-29 00:00 |
20:58:17.03 |
+06:21:39.2 |
HIP 103490 |
32.35 |
| 2026-07-29 12:00 |
20:58:15.23 |
+06:21:32.5 |
HIP 103490 |
32.42 |
| 2026-07-30 00:00 |
20:58:13.42 |
+06:21:25.7 |
HIP 103490 |
32.49 |
| 2026-07-30 12:00 |
20:58:11.61 |
+06:21:18.8 |
HIP 103327 |
32.26 |
| 2026-07-31 00:00 |
20:58:09.80 |
+06:21:11.8 |
HIP 103327 |
31.81 |
| 2026-07-31 12:00 |
20:58:07.99 |
+06:21:04.7 |
HIP 103327 |
31.36 |
| 2026-08-01 00:00 |
20:58:06.18 |
+06:20:57.4 |
HIP 103327 |
30.90 |
| 2026-08-01 12:00 |
20:58:04.37 |
+06:20:50.1 |
HIP 103327 |
30.45 |
| 2026-08-02 00:00 |
20:58:02.56 |
+06:20:42.7 |
HIP 103327 |
29.99 |
| 2026-08-02 12:00 |
20:58:00.74 |
+06:20:35.2 |
HIP 103327 |
29.54 |
| 2026-08-03 00:00 |
20:57:58.93 |
+06:20:27.5 |
HIP 103327 |
29.09 |
| 2026-08-03 12:00 |
20:57:57.11 |
+06:20:19.8 |
HIP 103327 |
28.63 |
| 2026-08-04 00:00 |
20:57:55.29 |
+06:20:12.0 |
HIP 103327 |
28.18 |
| 2026-08-04 12:00 |
20:57:53.48 |
+06:20:04.0 |
HIP 103327 |
27.73 |
| 2026-08-05 00:00 |
20:57:51.66 |
+06:19:56.0 |
HIP 103327 |
27.28 |
| 2026-08-05 12:00 |
20:57:49.84 |
+06:19:47.9 |
HIP 103327 |
26.83 |
| 2026-08-06 00:00 |
20:57:48.03 |
+06:19:39.7 |
HIP 103327 |
26.38 |
| 2026-08-06 12:00 |
20:57:46.21 |
+06:19:31.4 |
HIP 103327 |
25.93 |
| 2026-08-07 00:00 |
20:57:44.40 |
+06:19:22.9 |
HIP 103327 |
25.48 |
| 2026-08-07 12:00 |
20:57:42.58 |
+06:19:14.4 |
HIP 103327 |
25.03 |
| 2026-08-08 00:00 |
20:57:40.77 |
+06:19:05.8 |
HIP 103327 |
24.59 |
| 2026-08-08 12:00 |
20:57:38.96 |
+06:18:57.1 |
HIP 103327 |
24.14 |
| 2026-08-09 00:00 |
20:57:37.14 |
+06:18:48.3 |
HIP 103327 |
23.70 |
| 2026-08-09 12:00 |
20:57:35.33 |
+06:18:39.4 |
HIP 103327 |
23.26 |
| 2026-08-10 00:00 |
20:57:33.52 |
+06:18:30.4 |
HIP 103327 |
22.82 |
| 2026-08-10 12:00 |
20:57:31.71 |
+06:18:21.3 |
HIP 103327 |
22.38 |
| 2026-08-11 00:00 |
20:57:29.91 |
+06:18:12.2 |
HIP 103327 |
21.94 |
| 2026-08-11 12:00 |
20:57:28.10 |
+06:18:02.9 |
HIP 103327 |
21.51 |
| 2026-08-12 00:00 |
20:57:26.30 |
+06:17:53.5 |
HIP 103327 |
21.08 |
| 2026-08-12 12:00 |
20:57:24.50 |
+06:17:44.1 |
HIP 103327 |
20.65 |
| 2026-08-13 00:00 |
20:57:22.70 |
+06:17:34.6 |
HIP 103327 |
20.22 |
| 2026-08-13 12:00 |
20:57:20.90 |
+06:17:24.9 |
HIP 103327 |
19.80 |
| 2026-08-14 00:00 |
20:57:19.11 |
+06:17:15.2 |
HIP 103327 |
19.38 |
| 2026-08-14 12:00 |
20:57:17.32 |
+06:17:05.4 |
HIP 103327 |
18.96 |
| 2026-08-15 00:00 |
20:57:15.53 |
+06:16:55.5 |
HIP 103327 |
18.55 |
| 2026-08-15 12:00 |
20:57:13.74 |
+06:16:45.6 |
HIP 103327 |
18.14 |
| 2026-08-16 00:00 |
20:57:11.96 |
+06:16:35.5 |
HIP 103327 |
17.74 |
| 2026-08-16 12:00 |
20:57:10.18 |
+06:16:25.4 |
HIP 103327 |
17.34 |
| 2026-08-17 00:00 |
20:57:08.41 |
+06:16:15.1 |
HIP 103327 |
16.94 |
| 2026-08-17 12:00 |
20:57:06.64 |
+06:16:04.8 |
HIP 103327 |
16.55 |
| 2026-08-18 00:00 |
20:57:04.87 |
+06:15:54.4 |
HIP 103327 |
16.17 |
| 2026-08-18 12:00 |
20:57:03.10 |
+06:15:43.9 |
HIP 103327 |
15.79 |
| 2026-08-19 00:00 |
20:57:01.34 |
+06:15:33.4 |
HIP 103327 |
15.42 |