| 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) |
| 2026-07-29 00:00 |
07:23:38.24 |
-83:49:41.5 |
HIP 34905 |
17.48 |
| 2026-07-29 12:00 |
07:24:07.20 |
-83:49:55.8 |
HIP 34905 |
18.13 |
| 2026-07-30 00:00 |
07:24:36.13 |
-83:50:10.3 |
HIP 34905 |
18.79 |
| 2026-07-30 12:00 |
07:25:05.00 |
-83:50:25.1 |
HIP 34905 |
19.46 |
| 2026-07-31 00:00 |
07:25:33.84 |
-83:50:40.2 |
HIP 34905 |
20.14 |
| 2026-07-31 12:00 |
07:26:02.63 |
-83:50:55.5 |
HIP 34905 |
20.82 |
| 2026-08-01 00:00 |
07:26:31.38 |
-83:51:11.2 |
HIP 34905 |
21.51 |
| 2026-08-01 12:00 |
07:27:00.09 |
-83:51:27.1 |
HIP 34905 |
22.20 |
| 2026-08-02 00:00 |
07:27:28.74 |
-83:51:43.3 |
HIP 37226 |
22.85 |
| 2026-08-02 12:00 |
07:27:57.36 |
-83:51:59.8 |
HIP 37226 |
22.39 |
| 2026-08-03 00:00 |
07:28:25.92 |
-83:52:16.6 |
HIP 37226 |
21.96 |
| 2026-08-03 12:00 |
07:28:54.44 |
-83:52:33.6 |
HIP 37226 |
21.55 |
| 2026-08-04 00:00 |
07:29:22.90 |
-83:52:51.0 |
HIP 37226 |
21.18 |
| 2026-08-04 12:00 |
07:29:51.32 |
-83:53:08.6 |
HIP 37226 |
20.83 |
| 2026-08-05 00:00 |
07:30:19.68 |
-83:53:26.5 |
HIP 37226 |
20.52 |
| 2026-08-05 12:00 |
07:30:48.00 |
-83:53:44.7 |
HIP 37226 |
20.24 |
| 2026-08-06 00:00 |
07:31:16.26 |
-83:54:03.1 |
HIP 37226 |
20.00 |
| 2026-08-06 12:00 |
07:31:44.47 |
-83:54:21.9 |
HIP 37226 |
19.79 |
| 2026-08-07 00:00 |
07:32:12.62 |
-83:54:40.9 |
HIP 37226 |
19.62 |
| 2026-08-07 12:00 |
07:32:40.71 |
-83:55:00.2 |
HIP 37226 |
19.50 |
| 2026-08-08 00:00 |
07:33:08.75 |
-83:55:19.8 |
HIP 37226 |
19.41 |
| 2026-08-08 12:00 |
07:33:36.73 |
-83:55:39.7 |
HIP 37226 |
19.36 |
| 2026-08-09 00:00 |
07:34:04.66 |
-83:55:59.8 |
HIP 37226 |
19.35 |
| 2026-08-09 12:00 |
07:34:32.52 |
-83:56:20.2 |
HIP 37226 |
19.38 |
| 2026-08-10 00:00 |
07:35:00.32 |
-83:56:40.9 |
HIP 37226 |
19.46 |
| 2026-08-10 12:00 |
07:35:28.05 |
-83:57:01.9 |
HIP 37226 |
19.57 |
| 2026-08-11 00:00 |
07:35:55.73 |
-83:57:23.2 |
HIP 37226 |
19.73 |
| 2026-08-11 12:00 |
07:36:23.34 |
-83:57:44.7 |
HIP 37226 |
19.92 |
| 2026-08-12 00:00 |
07:36:50.88 |
-83:58:06.5 |
HIP 37226 |
20.15 |
| 2026-08-12 12:00 |
07:37:18.35 |
-83:58:28.6 |
HIP 37226 |
20.41 |
| 2026-08-13 00:00 |
07:37:45.76 |
-83:58:51.0 |
HIP 37226 |
20.71 |
| 2026-08-13 12:00 |
07:38:13.10 |
-83:59:13.6 |
HIP 37226 |
21.04 |
| 2026-08-14 00:00 |
07:38:40.36 |
-83:59:36.6 |
HIP 37226 |
21.41 |
| 2026-08-14 12:00 |
07:39:07.56 |
-83:59:59.7 |
HIP 37226 |
21.80 |
| 2026-08-15 00:00 |
07:39:34.68 |
-84:00:23.2 |
HIP 37226 |
22.22 |
| 2026-08-15 12:00 |
07:40:01.72 |
-84:00:47.0 |
HIP 37226 |
22.67 |
| 2026-08-16 00:00 |
07:40:28.69 |
-84:01:11.0 |
HIP 37226 |
23.15 |
| 2026-08-16 12:00 |
07:40:55.59 |
-84:01:35.2 |
HIP 37226 |
23.64 |
| 2026-08-17 00:00 |
07:41:22.40 |
-84:01:59.8 |
HIP 37226 |
24.16 |
| 2026-08-17 12:00 |
07:41:49.14 |
-84:02:24.6 |
HIP 37226 |
24.70 |
| 2026-08-18 00:00 |
07:42:15.80 |
-84:02:49.7 |
HIP 37226 |
25.26 |
| 2026-08-18 12:00 |
07:42:42.37 |
-84:03:15.0 |
HIP 37226 |
25.84 |
| 2026-08-19 00:00 |
07:43:08.87 |
-84:03:40.7 |
HIP 38537 |
26.21 |