C/2013 N4 (Borisov)
| Parameter |
Value |
| Designation |
C/2013 N4 (Borisov) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-08-21T12:19:51.456000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:37Z |
| Obs used |
287 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
5.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-09-15.0000000 |
| e |
0.97480289 |
| q (au) |
1.210405 |
| a (au) |
48.037448 |
| i (deg) |
37.035278 |
| Ω (om, deg) |
322.609954 |
| ω (w, deg) |
142.280706 |
| M (ma, deg) |
0.072486 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.680 + 4.775\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.680 |
| n |
4.775 |
| gf |
1.000 |
| gb |
-0.733 |
| k |
0.800 |
| 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 |
| 2013-07-08 |
2013-08-18 |
+21.8907 |
-2.670 |
| 2013-08-25 |
2013-12-11 |
-5.2553 |
-1.508 |
| 2013-12-11 |
2014-04-30 |
+14.2425 |
-6.622 |
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 |
18:10:54.21 |
-53:31:46.1 |
HIP 88949 |
31.36 |
| 2026-02-03 12:00 |
18:11:00.05 |
-53:32:05.5 |
HIP 88949 |
32.03 |
| 2026-02-04 00:00 |
18:11:05.85 |
-53:32:25.1 |
HIP 88949 |
32.72 |
| 2026-02-04 12:00 |
18:11:11.61 |
-53:32:44.8 |
HIP 88949 |
33.41 |
| 2026-02-05 00:00 |
18:11:17.33 |
-53:33:04.8 |
HIP 88949 |
34.12 |
| 2026-02-05 12:00 |
18:11:23.01 |
-53:33:25.0 |
HIP 88949 |
34.84 |
| 2026-02-06 00:00 |
18:11:28.64 |
-53:33:45.4 |
HIP 88949 |
35.56 |
| 2026-02-06 12:00 |
18:11:34.24 |
-53:34:05.9 |
HIP 88949 |
36.30 |
| 2026-02-07 00:00 |
18:11:39.79 |
-53:34:26.7 |
HIP 88949 |
37.03 |
| 2026-02-07 12:00 |
18:11:45.31 |
-53:34:47.7 |
HIP 89380 |
36.93 |
| 2026-02-08 00:00 |
18:11:50.78 |
-53:35:08.8 |
HIP 89380 |
36.15 |
| 2026-02-08 12:00 |
18:11:56.21 |
-53:35:30.2 |
HIP 89380 |
35.38 |
| 2026-02-09 00:00 |
18:12:01.59 |
-53:35:51.8 |
HIP 89380 |
34.61 |
| 2026-02-09 12:00 |
18:12:06.93 |
-53:36:13.5 |
HIP 89380 |
33.84 |
| 2026-02-10 00:00 |
18:12:12.23 |
-53:36:35.5 |
HIP 89380 |
33.08 |
| 2026-02-10 12:00 |
18:12:17.48 |
-53:36:57.6 |
HIP 89380 |
32.33 |
| 2026-02-11 00:00 |
18:12:22.69 |
-53:37:19.9 |
HIP 89380 |
31.59 |
| 2026-02-11 12:00 |
18:12:27.85 |
-53:37:42.4 |
HIP 89380 |
30.85 |
| 2026-02-12 00:00 |
18:12:32.97 |
-53:38:05.1 |
HIP 89380 |
30.12 |
| 2026-02-12 12:00 |
18:12:38.04 |
-53:38:28.0 |
HIP 89380 |
29.40 |
| 2026-02-13 00:00 |
18:12:43.07 |
-53:38:51.1 |
HIP 89380 |
28.68 |
| 2026-02-13 12:00 |
18:12:48.04 |
-53:39:14.3 |
HIP 89380 |
27.98 |
| 2026-02-14 00:00 |
18:12:52.98 |
-53:39:37.8 |
HIP 89380 |
27.28 |
| 2026-02-14 12:00 |
18:12:57.86 |
-53:40:01.4 |
HIP 89380 |
26.58 |
| 2026-02-15 00:00 |
18:13:02.70 |
-53:40:25.2 |
HIP 89380 |
25.90 |
| 2026-02-15 12:00 |
18:13:07.49 |
-53:40:49.1 |
HIP 89380 |
25.22 |
| 2026-02-16 00:00 |
18:13:12.23 |
-53:41:13.3 |
HIP 89380 |
24.56 |
| 2026-02-16 12:00 |
18:13:16.92 |
-53:41:37.6 |
HIP 89380 |
23.90 |
| 2026-02-17 00:00 |
18:13:21.56 |
-53:42:02.1 |
HIP 89380 |
23.25 |
| 2026-02-17 12:00 |
18:13:26.15 |
-53:42:26.8 |
HIP 89380 |
22.61 |
| 2026-02-18 00:00 |
18:13:30.69 |
-53:42:51.6 |
HIP 89380 |
21.98 |
| 2026-02-18 12:00 |
18:13:35.18 |
-53:43:16.6 |
HIP 89380 |
21.37 |
| 2026-02-19 00:00 |
18:13:39.63 |
-53:43:41.8 |
HIP 89380 |
20.76 |
| 2026-02-19 12:00 |
18:13:44.02 |
-53:44:07.1 |
HIP 89380 |
20.16 |
| 2026-02-20 00:00 |
18:13:48.35 |
-53:44:32.6 |
HIP 89380 |
19.58 |
| 2026-02-20 12:00 |
18:13:52.64 |
-53:44:58.3 |
HIP 89380 |
19.00 |
| 2026-02-21 00:00 |
18:13:56.88 |
-53:45:24.1 |
HIP 89380 |
18.44 |
| 2026-02-21 12:00 |
18:14:01.06 |
-53:45:50.1 |
HIP 89380 |
17.90 |
| 2026-02-22 00:00 |
18:14:05.19 |
-53:46:16.2 |
HIP 89380 |
17.37 |
| 2026-02-22 12:00 |
18:14:09.27 |
-53:46:42.5 |
HIP 89380 |
16.85 |
| 2026-02-23 00:00 |
18:14:13.29 |
-53:47:08.9 |
HIP 89380 |
16.35 |
| 2026-02-23 12:00 |
18:14:17.27 |
-53:47:35.5 |
HIP 89380 |
15.86 |
| 2026-02-24 00:00 |
18:14:21.18 |
-53:48:02.2 |
HIP 89380 |
15.39 |