C/2015 F3 (SWAN)
| 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 |
-0.999 |
| 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) |
| 2026-02-03 00:00 |
13:55:46.52 |
-50:33:17.5 |
HIP 68035 |
6.43 |
| 2026-02-03 12:00 |
13:55:44.99 |
-50:33:58.0 |
HIP 68035 |
5.81 |
| 2026-02-04 00:00 |
13:55:43.40 |
-50:34:38.4 |
HIP 68035 |
5.21 |
| 2026-02-04 12:00 |
13:55:41.76 |
-50:35:18.4 |
HIP 68035 |
4.66 |
| 2026-02-05 00:00 |
13:55:40.05 |
-50:35:58.3 |
HIP 68035 |
4.17 |
| 2026-02-05 12:00 |
13:55:38.29 |
-50:36:37.9 |
HIP 68035 |
3.76 |
| 2026-02-06 00:00 |
13:55:36.47 |
-50:37:17.3 |
HIP 68035 |
3.46 |
| 2026-02-06 12:00 |
13:55:34.59 |
-50:37:56.4 |
HIP 68035 |
3.30 |
| 2026-02-07 00:00 |
13:55:32.66 |
-50:38:35.3 |
HIP 68035 |
3.30 |
| 2026-02-07 12:00 |
13:55:30.67 |
-50:39:13.9 |
HIP 68035 |
3.47 |
| 2026-02-08 00:00 |
13:55:28.61 |
-50:39:52.3 |
HIP 68035 |
3.77 |
| 2026-02-08 12:00 |
13:55:26.51 |
-50:40:30.4 |
HIP 68035 |
4.19 |
| 2026-02-09 00:00 |
13:55:24.34 |
-50:41:08.3 |
HIP 67970 |
4.23 |
| 2026-02-09 12:00 |
13:55:22.12 |
-50:41:45.9 |
HIP 67970 |
3.51 |
| 2026-02-10 00:00 |
13:55:19.84 |
-50:42:23.3 |
HIP 67970 |
2.80 |
| 2026-02-10 12:00 |
13:55:17.50 |
-50:43:00.4 |
HIP 67970 |
2.08 |
| 2026-02-11 00:00 |
13:55:15.11 |
-50:43:37.2 |
HIP 67970 |
1.36 |
| 2026-02-11 12:00 |
13:55:12.66 |
-50:44:13.7 |
HIP 67970 |
0.64 |
| 2026-02-12 00:00 |
13:55:10.15 |
-50:44:50.0 |
HIP 67970 |
0.12 |
| 2026-02-12 12:00 |
13:55:07.59 |
-50:45:26.0 |
HIP 67970 |
0.82 |
| 2026-02-13 00:00 |
13:55:04.97 |
-50:46:01.7 |
HIP 67957 |
1.15 |
| 2026-02-13 12:00 |
13:55:02.29 |
-50:46:37.1 |
HIP 67957 |
1.59 |
| 2026-02-14 00:00 |
13:54:59.56 |
-50:47:12.2 |
HIP 67957 |
2.19 |
| 2026-02-14 12:00 |
13:54:56.77 |
-50:47:47.1 |
HIP 67957 |
2.84 |
| 2026-02-15 00:00 |
13:54:53.92 |
-50:48:21.6 |
HIP 67957 |
3.53 |
| 2026-02-15 12:00 |
13:54:51.02 |
-50:48:55.9 |
HIP 67957 |
4.22 |
| 2026-02-16 00:00 |
13:54:48.06 |
-50:49:29.8 |
HIP 67957 |
4.93 |
| 2026-02-16 12:00 |
13:54:45.05 |
-50:50:03.5 |
HIP 67957 |
5.64 |
| 2026-02-17 00:00 |
13:54:41.99 |
-50:50:36.8 |
HIP 67957 |
6.36 |
| 2026-02-17 12:00 |
13:54:38.86 |
-50:51:09.8 |
HIP 67957 |
7.08 |
| 2026-02-18 00:00 |
13:54:35.69 |
-50:51:42.5 |
HIP 67957 |
7.81 |
| 2026-02-18 12:00 |
13:54:32.46 |
-50:52:14.9 |
HIP 67957 |
8.54 |
| 2026-02-19 00:00 |
13:54:29.17 |
-50:52:47.0 |
HIP 67957 |
9.27 |
| 2026-02-19 12:00 |
13:54:25.83 |
-50:53:18.8 |
HIP 67957 |
10.00 |
| 2026-02-20 00:00 |
13:54:22.44 |
-50:53:50.2 |
HIP 67957 |
10.73 |
| 2026-02-20 12:00 |
13:54:19.00 |
-50:54:21.3 |
HIP 67957 |
11.47 |
| 2026-02-21 00:00 |
13:54:15.50 |
-50:54:52.1 |
HIP 67957 |
12.21 |
| 2026-02-21 12:00 |
13:54:11.94 |
-50:55:22.6 |
HIP 67957 |
12.95 |
| 2026-02-22 00:00 |
13:54:08.34 |
-50:55:52.7 |
HIP 67957 |
13.70 |
| 2026-02-22 12:00 |
13:54:04.68 |
-50:56:22.5 |
HIP 67742 |
13.95 |
| 2026-02-23 00:00 |
13:54:00.97 |
-50:56:51.9 |
HIP 67742 |
13.42 |
| 2026-02-23 12:00 |
13:53:57.21 |
-50:57:21.0 |
HIP 67742 |
12.89 |
| 2026-02-24 00:00 |
13:53:53.40 |
-50:57:49.8 |
HIP 67742 |
12.39 |