| Parameter |
Value |
| Designation |
C/2009 F6 (Yi-SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2009-05-07T10:24:24.171840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:30Z |
| Obs used |
487 |
| NEO |
- |
| M1 |
9.700 |
| K1 |
13.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-05-22.0000000 |
| e |
0.99751434 |
| q (au) |
1.274159 |
| a (au) |
512.604406 |
| i (deg) |
85.764786 |
| Ω (om, deg) |
278.679026 |
| ω (w, deg) |
129.772327 |
| M (ma, deg) |
0.001237 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.977 + 4.261\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.977 |
| n |
4.261 |
| 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) |
| 2026-05-12 00:00 |
06:09:21.49 |
-84:11:06.9 |
HIP 30523 |
32.35 |
| 2026-05-12 12:00 |
06:09:45.78 |
-84:10:37.7 |
HIP 30523 |
31.56 |
| 2026-05-13 00:00 |
06:10:10.18 |
-84:10:08.7 |
HIP 30523 |
30.78 |
| 2026-05-13 12:00 |
06:10:34.70 |
-84:09:39.9 |
HIP 30523 |
29.99 |
| 2026-05-14 00:00 |
06:10:59.32 |
-84:09:11.4 |
HIP 30523 |
29.21 |
| 2026-05-14 12:00 |
06:11:24.06 |
-84:08:43.1 |
HIP 30523 |
28.42 |
| 2026-05-15 00:00 |
06:11:48.91 |
-84:08:15.0 |
HIP 30523 |
27.63 |
| 2026-05-15 12:00 |
06:12:13.87 |
-84:07:47.3 |
HIP 30523 |
26.85 |
| 2026-05-16 00:00 |
06:12:38.94 |
-84:07:19.7 |
HIP 30523 |
26.06 |
| 2026-05-16 12:00 |
06:13:04.10 |
-84:06:52.4 |
HIP 30523 |
25.28 |
| 2026-05-17 00:00 |
06:13:29.38 |
-84:06:25.3 |
HIP 30523 |
24.49 |
| 2026-05-17 12:00 |
06:13:54.75 |
-84:05:58.5 |
HIP 30523 |
23.71 |
| 2026-05-18 00:00 |
06:14:20.23 |
-84:05:32.0 |
HIP 30523 |
22.92 |
| 2026-05-18 12:00 |
06:14:45.80 |
-84:05:05.7 |
HIP 30523 |
22.14 |
| 2026-05-19 00:00 |
06:15:11.48 |
-84:04:39.6 |
HIP 30523 |
21.36 |
| 2026-05-19 12:00 |
06:15:37.24 |
-84:04:13.8 |
HIP 30523 |
20.58 |
| 2026-05-20 00:00 |
06:16:03.11 |
-84:03:48.3 |
HIP 30523 |
19.80 |
| 2026-05-20 12:00 |
06:16:29.06 |
-84:03:23.0 |
HIP 30523 |
19.03 |
| 2026-05-21 00:00 |
06:16:55.11 |
-84:02:58.0 |
HIP 30523 |
18.25 |
| 2026-05-21 12:00 |
06:17:21.25 |
-84:02:33.2 |
HIP 30523 |
17.48 |
| 2026-05-22 00:00 |
06:17:47.48 |
-84:02:08.7 |
HIP 30523 |
16.72 |
| 2026-05-22 12:00 |
06:18:13.79 |
-84:01:44.4 |
HIP 30523 |
15.95 |
| 2026-05-23 00:00 |
06:18:40.19 |
-84:01:20.4 |
HIP 30523 |
15.20 |
| 2026-05-23 12:00 |
06:19:06.67 |
-84:00:56.7 |
HIP 30523 |
14.45 |
| 2026-05-24 00:00 |
06:19:33.24 |
-84:00:33.2 |
HIP 30523 |
13.70 |
| 2026-05-24 12:00 |
06:19:59.89 |
-84:00:10.0 |
HIP 30523 |
12.96 |
| 2026-05-25 00:00 |
06:20:26.62 |
-83:59:47.0 |
HIP 30523 |
12.24 |
| 2026-05-25 12:00 |
06:20:53.43 |
-83:59:24.3 |
HIP 30523 |
11.52 |
| 2026-05-26 00:00 |
06:21:20.32 |
-83:59:01.8 |
HIP 30523 |
10.82 |
| 2026-05-26 12:00 |
06:21:47.29 |
-83:58:39.7 |
HIP 30523 |
10.14 |
| 2026-05-27 00:00 |
06:22:14.33 |
-83:58:17.7 |
HIP 30523 |
9.48 |
| 2026-05-27 12:00 |
06:22:41.45 |
-83:57:56.1 |
HIP 30523 |
8.85 |
| 2026-05-28 00:00 |
06:23:08.64 |
-83:57:34.7 |
HIP 30523 |
8.25 |
| 2026-05-28 12:00 |
06:23:35.90 |
-83:57:13.6 |
HIP 30523 |
7.69 |
| 2026-05-29 00:00 |
06:24:03.24 |
-83:56:52.7 |
HIP 30523 |
7.18 |
| 2026-05-29 12:00 |
06:24:30.64 |
-83:56:32.1 |
HIP 30523 |
6.73 |
| 2026-05-30 00:00 |
06:24:58.12 |
-83:56:11.8 |
HIP 30523 |
6.36 |
| 2026-05-30 12:00 |
06:25:25.66 |
-83:55:51.7 |
HIP 30523 |
6.08 |
| 2026-05-31 00:00 |
06:25:53.27 |
-83:55:31.9 |
HIP 30523 |
5.90 |
| 2026-05-31 12:00 |
06:26:20.95 |
-83:55:12.3 |
HIP 30523 |
5.83 |
| 2026-06-01 00:00 |
06:26:48.70 |
-83:54:53.1 |
HIP 30523 |
5.88 |
| 2026-06-01 12:00 |
06:27:16.51 |
-83:54:34.1 |
HIP 30523 |
6.04 |
| 2026-06-02 00:00 |
06:27:44.38 |
-83:54:15.3 |
HIP 30523 |
6.31 |