| Parameter |
Value |
| Designation |
C/2015 F3 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-03-09T08:31:54.042240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:09Z |
| Obs used |
316 |
| NEO |
- |
| M1 |
14.200 |
| K1 |
8.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-04-16.0000000 |
| e |
0.99638676 |
| q (au) |
0.834438 |
| a (au) |
230.939218 |
| i (deg) |
73.386412 |
| Ω (om, deg) |
31.639644 |
| ω (w, deg) |
57.566073 |
| M (ma, deg) |
0.010572 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.649 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.649 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2015-03-24 |
2015-05-30 |
+6.9369 |
-1.877 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
13:31:20.53 |
-49:08:59.1 |
HIP 65917 |
13.44 |
| 2026-07-29 12:00 |
13:31:21.76 |
-49:08:25.8 |
HIP 65917 |
14.03 |
| 2026-07-30 00:00 |
13:31:23.04 |
-49:07:52.7 |
HIP 65917 |
14.62 |
| 2026-07-30 12:00 |
13:31:24.37 |
-49:07:19.9 |
HIP 65917 |
15.20 |
| 2026-07-31 00:00 |
13:31:25.75 |
-49:06:47.3 |
HIP 65917 |
15.79 |
| 2026-07-31 12:00 |
13:31:27.18 |
-49:06:14.9 |
HIP 65917 |
16.38 |
| 2026-08-01 00:00 |
13:31:28.66 |
-49:05:42.8 |
HIP 65917 |
16.97 |
| 2026-08-01 12:00 |
13:31:30.19 |
-49:05:11.0 |
HIP 65917 |
17.55 |
| 2026-08-02 00:00 |
13:31:31.76 |
-49:04:39.4 |
HIP 65917 |
18.14 |
| 2026-08-02 12:00 |
13:31:33.39 |
-49:04:08.1 |
HIP 65917 |
18.72 |
| 2026-08-03 00:00 |
13:31:35.06 |
-49:03:37.0 |
HIP 65917 |
19.31 |
| 2026-08-03 12:00 |
13:31:36.78 |
-49:03:06.2 |
HIP 65917 |
19.89 |
| 2026-08-04 00:00 |
13:31:38.54 |
-49:02:35.6 |
HIP 65917 |
20.47 |
| 2026-08-04 12:00 |
13:31:40.36 |
-49:02:05.3 |
HIP 65917 |
21.06 |
| 2026-08-05 00:00 |
13:31:42.22 |
-49:01:35.3 |
HIP 65917 |
21.64 |
| 2026-08-05 12:00 |
13:31:44.13 |
-49:01:05.5 |
HIP 66156 |
21.31 |
| 2026-08-06 00:00 |
13:31:46.08 |
-49:00:36.0 |
HIP 66156 |
20.79 |
| 2026-08-06 12:00 |
13:31:48.08 |
-49:00:06.8 |
HIP 66156 |
20.28 |
| 2026-08-07 00:00 |
13:31:50.13 |
-48:59:37.8 |
HIP 66156 |
19.76 |
| 2026-08-07 12:00 |
13:31:52.23 |
-48:59:09.1 |
HIP 66156 |
19.25 |
| 2026-08-08 00:00 |
13:31:54.37 |
-48:58:40.7 |
HIP 66156 |
18.73 |
| 2026-08-08 12:00 |
13:31:56.56 |
-48:58:12.6 |
HIP 66156 |
18.21 |
| 2026-08-09 00:00 |
13:31:58.80 |
-48:57:44.8 |
HIP 66156 |
17.70 |
| 2026-08-09 12:00 |
13:32:01.08 |
-48:57:17.2 |
HIP 66156 |
17.18 |
| 2026-08-10 00:00 |
13:32:03.40 |
-48:56:49.9 |
HIP 66156 |
16.66 |
| 2026-08-10 12:00 |
13:32:05.78 |
-48:56:23.0 |
HIP 66156 |
16.14 |
| 2026-08-11 00:00 |
13:32:08.19 |
-48:55:56.3 |
HIP 66156 |
15.62 |
| 2026-08-11 12:00 |
13:32:10.66 |
-48:55:29.9 |
HIP 66156 |
15.10 |
| 2026-08-12 00:00 |
13:32:13.17 |
-48:55:03.8 |
HIP 66156 |
14.58 |
| 2026-08-12 12:00 |
13:32:15.72 |
-48:54:38.0 |
HIP 66156 |
14.06 |
| 2026-08-13 00:00 |
13:32:18.32 |
-48:54:12.5 |
HIP 66156 |
13.54 |
| 2026-08-13 12:00 |
13:32:20.96 |
-48:53:47.2 |
HIP 66156 |
13.02 |
| 2026-08-14 00:00 |
13:32:23.64 |
-48:53:22.3 |
HIP 66156 |
12.51 |
| 2026-08-14 12:00 |
13:32:26.37 |
-48:52:57.7 |
HIP 66156 |
11.99 |
| 2026-08-15 00:00 |
13:32:29.15 |
-48:52:33.4 |
HIP 66156 |
11.48 |
| 2026-08-15 12:00 |
13:32:31.96 |
-48:52:09.4 |
HIP 66156 |
10.97 |
| 2026-08-16 00:00 |
13:32:34.82 |
-48:51:45.7 |
HIP 66156 |
10.47 |
| 2026-08-16 12:00 |
13:32:37.72 |
-48:51:22.4 |
HIP 66156 |
9.97 |
| 2026-08-17 00:00 |
13:32:40.67 |
-48:50:59.3 |
HIP 66156 |
9.48 |
| 2026-08-17 12:00 |
13:32:43.65 |
-48:50:36.5 |
HIP 66156 |
8.99 |
| 2026-08-18 00:00 |
13:32:46.68 |
-48:50:14.1 |
HIP 66156 |
8.52 |
| 2026-08-18 12:00 |
13:32:49.75 |
-48:49:52.0 |
HIP 66156 |
8.06 |
| 2026-08-19 00:00 |
13:32:52.86 |
-48:49:30.1 |
HIP 66156 |
7.62 |