C/2014 A4 (SONEAR)
| Parameter |
Value |
| Designation |
C/2014 A4 (SONEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-09-05T20:45:05.630400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:46Z |
| Obs used |
2742 |
| NEO |
- |
| M1 |
9.500 |
| K1 |
5.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-10-28.0000000 |
| e |
1.00085476 |
| q (au) |
4.180180 |
| a (au) |
-4890.464363 |
| i (deg) |
121.359968 |
| Ω (om, deg) |
29.727220 |
| ω (w, deg) |
356.788414 |
| M (ma, deg) |
0.000150 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.149 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.149 |
| n |
2.000 |
| gf |
0.830 |
| gb |
-0.500 |
| k |
0.927 |
| δ90 |
1.000 |
| 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 |
| 2014-01-12 |
2014-10-21 |
+6.8415 |
-5.586 |
| 2014-10-21 |
2015-09-01 |
-9.4186 |
+6.023 |
| 2015-09-06 |
2017-02-01 |
-2.1564 |
+1.520 |
| 2017-02-01 |
2017-09-17 |
+21.6964 |
-16.924 |
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 |
16:50:29.73 |
+20:31:00.0 |
HIP 82505 |
18.05 |
| 2026-02-03 12:00 |
16:50:31.85 |
+20:31:36.7 |
HIP 82505 |
17.46 |
| 2026-02-04 00:00 |
16:50:33.93 |
+20:32:13.7 |
HIP 82505 |
16.89 |
| 2026-02-04 12:00 |
16:50:35.97 |
+20:32:51.0 |
HIP 82505 |
16.34 |
| 2026-02-05 00:00 |
16:50:37.97 |
+20:33:28.6 |
HIP 82505 |
15.82 |
| 2026-02-05 12:00 |
16:50:39.93 |
+20:34:06.4 |
HIP 82505 |
15.34 |
| 2026-02-06 00:00 |
16:50:41.85 |
+20:34:44.5 |
HIP 82505 |
14.89 |
| 2026-02-06 12:00 |
16:50:43.72 |
+20:35:22.9 |
HIP 82505 |
14.47 |
| 2026-02-07 00:00 |
16:50:45.56 |
+20:36:01.5 |
HIP 82505 |
14.10 |
| 2026-02-07 12:00 |
16:50:47.36 |
+20:36:40.5 |
HIP 82505 |
13.78 |
| 2026-02-08 00:00 |
16:50:49.11 |
+20:37:19.6 |
HIP 82505 |
13.49 |
| 2026-02-08 12:00 |
16:50:50.82 |
+20:37:59.1 |
HIP 82505 |
13.26 |
| 2026-02-09 00:00 |
16:50:52.50 |
+20:38:38.8 |
HIP 82505 |
13.08 |
| 2026-02-09 12:00 |
16:50:54.13 |
+20:39:18.7 |
HIP 82505 |
12.96 |
| 2026-02-10 00:00 |
16:50:55.71 |
+20:39:58.9 |
HIP 82505 |
12.89 |
| 2026-02-10 12:00 |
16:50:57.26 |
+20:40:39.4 |
HIP 82505 |
12.87 |
| 2026-02-11 00:00 |
16:50:58.76 |
+20:41:20.0 |
HIP 82505 |
12.92 |
| 2026-02-11 12:00 |
16:51:00.22 |
+20:42:01.0 |
HIP 82505 |
13.01 |
| 2026-02-12 00:00 |
16:51:01.63 |
+20:42:42.1 |
HIP 82505 |
13.16 |
| 2026-02-12 12:00 |
16:51:03.01 |
+20:43:23.5 |
HIP 82505 |
13.37 |
| 2026-02-13 00:00 |
16:51:04.33 |
+20:44:05.1 |
HIP 82505 |
13.62 |
| 2026-02-13 12:00 |
16:51:05.62 |
+20:44:47.0 |
HIP 82505 |
13.92 |
| 2026-02-14 00:00 |
16:51:06.86 |
+20:45:29.1 |
HIP 82505 |
14.26 |
| 2026-02-14 12:00 |
16:51:08.06 |
+20:46:11.4 |
HIP 82505 |
14.65 |
| 2026-02-15 00:00 |
16:51:09.21 |
+20:46:53.9 |
HIP 82505 |
15.07 |
| 2026-02-15 12:00 |
16:51:10.32 |
+20:47:36.6 |
HIP 82505 |
15.52 |
| 2026-02-16 00:00 |
16:51:11.39 |
+20:48:19.5 |
HIP 82505 |
16.01 |
| 2026-02-16 12:00 |
16:51:12.41 |
+20:49:02.7 |
HIP 82505 |
16.52 |
| 2026-02-17 00:00 |
16:51:13.38 |
+20:49:46.0 |
HIP 82505 |
17.06 |
| 2026-02-17 12:00 |
16:51:14.31 |
+20:50:29.5 |
HIP 82505 |
17.63 |
| 2026-02-18 00:00 |
16:51:15.20 |
+20:51:13.3 |
HIP 82505 |
18.21 |
| 2026-02-18 12:00 |
16:51:16.04 |
+20:51:57.2 |
HIP 82505 |
18.82 |
| 2026-02-19 00:00 |
16:51:16.83 |
+20:52:41.3 |
HIP 82505 |
19.44 |
| 2026-02-19 12:00 |
16:51:17.58 |
+20:53:25.6 |
HIP 82566 |
19.96 |
| 2026-02-20 00:00 |
16:51:18.28 |
+20:54:10.1 |
HIP 82566 |
19.62 |
| 2026-02-20 12:00 |
16:51:18.94 |
+20:54:54.7 |
HIP 82566 |
19.33 |
| 2026-02-21 00:00 |
16:51:19.55 |
+20:55:39.5 |
HIP 82566 |
19.06 |
| 2026-02-21 12:00 |
16:51:20.12 |
+20:56:24.5 |
HIP 82566 |
18.84 |
| 2026-02-22 00:00 |
16:51:20.64 |
+20:57:09.6 |
HIP 82566 |
18.65 |
| 2026-02-22 12:00 |
16:51:21.11 |
+20:57:54.9 |
HIP 82566 |
18.50 |
| 2026-02-23 00:00 |
16:51:21.54 |
+20:58:40.4 |
HIP 82566 |
18.40 |
| 2026-02-23 12:00 |
16:51:21.92 |
+20:59:26.0 |
HIP 82566 |
18.33 |
| 2026-02-24 00:00 |
16:51:22.25 |
+21:00:11.7 |
HIP 82566 |
18.31 |