| 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) |
| 2026-09-25 00:00 |
13:38:18.78 |
-48:38:10.3 |
HIP 66603 |
13.09 |
| 2026-09-25 12:00 |
13:38:24.20 |
-48:38:14.2 |
HIP 66603 |
12.48 |
| 2026-09-26 00:00 |
13:38:29.63 |
-48:38:18.5 |
HIP 66603 |
11.90 |
| 2026-09-26 12:00 |
13:38:35.08 |
-48:38:23.1 |
HIP 66603 |
11.35 |
| 2026-09-27 00:00 |
13:38:40.54 |
-48:38:28.1 |
HIP 66603 |
10.85 |
| 2026-09-27 12:00 |
13:38:46.03 |
-48:38:33.4 |
HIP 66603 |
10.39 |
| 2026-09-28 00:00 |
13:38:51.53 |
-48:38:39.0 |
HIP 66603 |
9.99 |
| 2026-09-28 12:00 |
13:38:57.05 |
-48:38:45.0 |
HIP 66603 |
9.65 |
| 2026-09-29 00:00 |
13:39:02.58 |
-48:38:51.4 |
HIP 66603 |
9.38 |
| 2026-09-29 12:00 |
13:39:08.13 |
-48:38:58.1 |
HIP 66603 |
9.19 |
| 2026-09-30 00:00 |
13:39:13.70 |
-48:39:05.1 |
HIP 66603 |
9.08 |
| 2026-09-30 12:00 |
13:39:19.28 |
-48:39:12.5 |
HIP 66603 |
9.07 |
| 2026-10-01 00:00 |
13:39:24.88 |
-48:39:20.2 |
HIP 66603 |
9.14 |
| 2026-10-01 12:00 |
13:39:30.50 |
-48:39:28.3 |
HIP 66603 |
9.30 |
| 2026-10-02 00:00 |
13:39:36.13 |
-48:39:36.7 |
HIP 66603 |
9.55 |
| 2026-10-02 12:00 |
13:39:41.77 |
-48:39:45.5 |
HIP 66603 |
9.88 |
| 2026-10-03 00:00 |
13:39:47.43 |
-48:39:54.6 |
HIP 66603 |
10.28 |
| 2026-10-03 12:00 |
13:39:53.10 |
-48:40:04.1 |
HIP 66603 |
10.74 |
| 2026-10-04 00:00 |
13:39:58.78 |
-48:40:13.9 |
HIP 66603 |
11.27 |
| 2026-10-04 12:00 |
13:40:04.48 |
-48:40:24.0 |
HIP 66603 |
11.84 |
| 2026-10-05 00:00 |
13:40:10.19 |
-48:40:34.5 |
HIP 66603 |
12.46 |
| 2026-10-05 12:00 |
13:40:15.91 |
-48:40:45.4 |
HIP 66603 |
13.12 |
| 2026-10-06 00:00 |
13:40:21.64 |
-48:40:56.5 |
HIP 66603 |
13.81 |
| 2026-10-06 12:00 |
13:40:27.39 |
-48:41:08.1 |
HIP 66603 |
14.53 |
| 2026-10-07 00:00 |
13:40:33.14 |
-48:41:19.9 |
HIP 66603 |
15.28 |
| 2026-10-07 12:00 |
13:40:38.91 |
-48:41:32.1 |
HIP 66603 |
16.05 |
| 2026-10-08 00:00 |
13:40:44.69 |
-48:41:44.7 |
HIP 66603 |
16.84 |
| 2026-10-08 12:00 |
13:40:50.48 |
-48:41:57.6 |
HIP 66603 |
17.65 |
| 2026-10-09 00:00 |
13:40:56.28 |
-48:42:10.8 |
HIP 66854 |
18.09 |
| 2026-10-09 12:00 |
13:41:02.08 |
-48:42:24.3 |
HIP 66854 |
17.70 |
| 2026-10-10 00:00 |
13:41:07.90 |
-48:42:38.2 |
HIP 66854 |
17.36 |
| 2026-10-10 12:00 |
13:41:13.72 |
-48:42:52.5 |
HIP 66854 |
17.08 |
| 2026-10-11 00:00 |
13:41:19.56 |
-48:43:07.0 |
HIP 66854 |
16.85 |
| 2026-10-11 12:00 |
13:41:25.40 |
-48:43:21.9 |
HIP 66854 |
16.69 |
| 2026-10-12 00:00 |
13:41:31.24 |
-48:43:37.2 |
HIP 66854 |
16.58 |
| 2026-10-12 12:00 |
13:41:37.10 |
-48:43:52.7 |
HIP 66854 |
16.55 |
| 2026-10-13 00:00 |
13:41:42.96 |
-48:44:08.6 |
HIP 66854 |
16.57 |
| 2026-10-13 12:00 |
13:41:48.83 |
-48:44:24.9 |
HIP 66854 |
16.67 |
| 2026-10-14 00:00 |
13:41:54.70 |
-48:44:41.4 |
HIP 66854 |
16.83 |
| 2026-10-14 12:00 |
13:42:00.58 |
-48:44:58.3 |
HIP 66854 |
17.05 |
| 2026-10-15 00:00 |
13:42:06.46 |
-48:45:15.5 |
HIP 66854 |
17.34 |
| 2026-10-15 12:00 |
13:42:12.35 |
-48:45:33.1 |
HIP 66854 |
17.68 |
| 2026-10-16 00:00 |
13:42:18.24 |
-48:45:50.9 |
HIP 66854 |
18.08 |