| Parameter |
Value |
| Designation |
C/1988 Y1 (Yanaka) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-12-11T15:40:33.395520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
56 |
| NEO |
- |
| M1 |
12.800 |
| K1 |
15.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1989-01-12.0000000 |
| e |
1.00000000 |
| q (au) |
0.427814 |
| a (au) |
- |
| i (deg) |
71.010955 |
| Ω (om, deg) |
315.523025 |
| ω (w, deg) |
88.122151 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (13.086 + 5.655\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.086 |
| n |
5.655 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-07-29 00:00 |
09:25:07.95 |
-61:33:34.1 |
HIP 46101 |
9.16 |
| 2026-07-29 12:00 |
09:25:11.58 |
-61:33:30.6 |
HIP 46101 |
9.54 |
| 2026-07-30 00:00 |
09:25:15.21 |
-61:33:27.3 |
HIP 46101 |
9.93 |
| 2026-07-30 12:00 |
09:25:18.85 |
-61:33:24.2 |
HIP 46101 |
10.32 |
| 2026-07-31 00:00 |
09:25:22.50 |
-61:33:21.3 |
HIP 46101 |
10.72 |
| 2026-07-31 12:00 |
09:25:26.16 |
-61:33:18.7 |
HIP 46101 |
11.11 |
| 2026-08-01 00:00 |
09:25:29.81 |
-61:33:16.2 |
HIP 46101 |
11.51 |
| 2026-08-01 12:00 |
09:25:33.48 |
-61:33:14.0 |
HIP 46101 |
11.91 |
| 2026-08-02 00:00 |
09:25:37.15 |
-61:33:12.0 |
HIP 46101 |
12.31 |
| 2026-08-02 12:00 |
09:25:40.82 |
-61:33:10.3 |
HIP 46101 |
12.71 |
| 2026-08-03 00:00 |
09:25:44.50 |
-61:33:08.8 |
HIP 46101 |
13.11 |
| 2026-08-03 12:00 |
09:25:48.18 |
-61:33:07.4 |
HIP 46101 |
13.52 |
| 2026-08-04 00:00 |
09:25:51.86 |
-61:33:06.4 |
HIP 46178 |
13.82 |
| 2026-08-04 12:00 |
09:25:55.55 |
-61:33:05.5 |
HIP 46178 |
14.02 |
| 2026-08-05 00:00 |
09:25:59.25 |
-61:33:04.8 |
HIP 46178 |
14.22 |
| 2026-08-05 12:00 |
09:26:02.94 |
-61:33:04.4 |
HIP 46178 |
14.45 |
| 2026-08-06 00:00 |
09:26:06.64 |
-61:33:04.2 |
HIP 46178 |
14.68 |
| 2026-08-06 12:00 |
09:26:10.35 |
-61:33:04.3 |
HIP 46178 |
14.93 |
| 2026-08-07 00:00 |
09:26:14.05 |
-61:33:04.5 |
HIP 46178 |
15.19 |
| 2026-08-07 12:00 |
09:26:17.76 |
-61:33:05.0 |
HIP 46178 |
15.46 |
| 2026-08-08 00:00 |
09:26:21.47 |
-61:33:05.7 |
HIP 46178 |
15.74 |
| 2026-08-08 12:00 |
09:26:25.18 |
-61:33:06.6 |
HIP 46178 |
16.03 |
| 2026-08-09 00:00 |
09:26:28.90 |
-61:33:07.8 |
HIP 46178 |
16.34 |
| 2026-08-09 12:00 |
09:26:32.61 |
-61:33:09.2 |
HIP 46178 |
16.65 |
| 2026-08-10 00:00 |
09:26:36.33 |
-61:33:10.8 |
HIP 46178 |
16.97 |
| 2026-08-10 12:00 |
09:26:40.05 |
-61:33:12.6 |
HIP 46178 |
17.30 |
| 2026-08-11 00:00 |
09:26:43.76 |
-61:33:14.7 |
HIP 46178 |
17.63 |
| 2026-08-11 12:00 |
09:26:47.48 |
-61:33:17.0 |
HIP 46178 |
17.98 |
| 2026-08-12 00:00 |
09:26:51.20 |
-61:33:19.5 |
HIP 46178 |
18.33 |
| 2026-08-12 12:00 |
09:26:54.92 |
-61:33:22.2 |
HIP 46178 |
18.69 |
| 2026-08-13 00:00 |
09:26:58.64 |
-61:33:25.2 |
HIP 46178 |
19.05 |
| 2026-08-13 12:00 |
09:27:02.36 |
-61:33:28.4 |
HIP 46178 |
19.42 |
| 2026-08-14 00:00 |
09:27:06.07 |
-61:33:31.8 |
HIP 46178 |
19.79 |
| 2026-08-14 12:00 |
09:27:09.79 |
-61:33:35.4 |
HIP 46579 |
19.69 |
| 2026-08-15 00:00 |
09:27:13.50 |
-61:33:39.3 |
HIP 46579 |
19.24 |
| 2026-08-15 12:00 |
09:27:17.21 |
-61:33:43.3 |
HIP 46579 |
18.80 |
| 2026-08-16 00:00 |
09:27:20.93 |
-61:33:47.7 |
HIP 46579 |
18.35 |
| 2026-08-16 12:00 |
09:27:24.63 |
-61:33:52.2 |
HIP 46579 |
17.91 |
| 2026-08-17 00:00 |
09:27:28.34 |
-61:33:56.9 |
HIP 46579 |
17.46 |
| 2026-08-17 12:00 |
09:27:32.04 |
-61:34:01.9 |
HIP 46579 |
17.02 |
| 2026-08-18 00:00 |
09:27:35.74 |
-61:34:07.1 |
HIP 46579 |
16.58 |
| 2026-08-18 12:00 |
09:27:39.44 |
-61:34:12.5 |
HIP 46579 |
16.14 |
| 2026-08-19 00:00 |
09:27:43.14 |
-61:34:18.2 |
HIP 46579 |
15.70 |