| 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) |
| 2026-09-20 00:00 |
17:50:15.84 |
-54:11:01.8 |
HIP 87366 |
8.73 |
| 2026-09-20 12:00 |
17:50:16.29 |
-54:10:28.2 |
HIP 87366 |
9.00 |
| 2026-09-21 00:00 |
17:50:16.80 |
-54:09:54.6 |
HIP 87366 |
9.30 |
| 2026-09-21 12:00 |
17:50:17.36 |
-54:09:21.0 |
HIP 87366 |
9.61 |
| 2026-09-22 00:00 |
17:50:17.99 |
-54:08:47.5 |
HIP 87366 |
9.93 |
| 2026-09-22 12:00 |
17:50:18.69 |
-54:08:14.0 |
HIP 87366 |
10.27 |
| 2026-09-23 00:00 |
17:50:19.44 |
-54:07:40.6 |
HIP 87366 |
10.62 |
| 2026-09-23 12:00 |
17:50:20.25 |
-54:07:07.2 |
HIP 87366 |
10.99 |
| 2026-09-24 00:00 |
17:50:21.12 |
-54:06:33.8 |
HIP 87366 |
11.37 |
| 2026-09-24 12:00 |
17:50:22.05 |
-54:06:00.5 |
HIP 87366 |
11.75 |
| 2026-09-25 00:00 |
17:50:23.05 |
-54:05:27.2 |
HIP 87366 |
12.15 |
| 2026-09-25 12:00 |
17:50:24.10 |
-54:04:54.0 |
HIP 87366 |
12.55 |
| 2026-09-26 00:00 |
17:50:25.21 |
-54:04:20.8 |
HIP 87366 |
12.97 |
| 2026-09-26 12:00 |
17:50:26.39 |
-54:03:47.7 |
HIP 87366 |
13.39 |
| 2026-09-27 00:00 |
17:50:27.62 |
-54:03:14.6 |
HIP 87366 |
13.82 |
| 2026-09-27 12:00 |
17:50:28.91 |
-54:02:41.6 |
HIP 87366 |
14.25 |
| 2026-09-28 00:00 |
17:50:30.27 |
-54:02:08.6 |
HIP 87386 |
14.37 |
| 2026-09-28 12:00 |
17:50:31.68 |
-54:01:35.7 |
HIP 87386 |
13.80 |
| 2026-09-29 00:00 |
17:50:33.15 |
-54:01:02.9 |
HIP 87386 |
13.23 |
| 2026-09-29 12:00 |
17:50:34.68 |
-54:00:30.1 |
HIP 87386 |
12.66 |
| 2026-09-30 00:00 |
17:50:36.27 |
-53:59:57.4 |
HIP 87386 |
12.08 |
| 2026-09-30 12:00 |
17:50:37.91 |
-53:59:24.7 |
HIP 87386 |
11.51 |
| 2026-10-01 00:00 |
17:50:39.62 |
-53:58:52.2 |
HIP 87386 |
10.92 |
| 2026-10-01 12:00 |
17:50:41.38 |
-53:58:19.7 |
HIP 87386 |
10.34 |
| 2026-10-02 00:00 |
17:50:43.21 |
-53:57:47.2 |
HIP 87386 |
9.75 |
| 2026-10-02 12:00 |
17:50:45.09 |
-53:57:14.9 |
HIP 87386 |
9.16 |
| 2026-10-03 00:00 |
17:50:47.03 |
-53:56:42.6 |
HIP 87386 |
8.57 |
| 2026-10-03 12:00 |
17:50:49.03 |
-53:56:10.4 |
HIP 87386 |
7.98 |
| 2026-10-04 00:00 |
17:50:51.08 |
-53:55:38.3 |
HIP 87386 |
7.38 |
| 2026-10-04 12:00 |
17:50:53.20 |
-53:55:06.3 |
HIP 87386 |
6.78 |
| 2026-10-05 00:00 |
17:50:55.37 |
-53:54:34.4 |
HIP 87386 |
6.18 |
| 2026-10-05 12:00 |
17:50:57.60 |
-53:54:02.5 |
HIP 87386 |
5.58 |
| 2026-10-06 00:00 |
17:50:59.88 |
-53:53:30.7 |
HIP 87386 |
4.98 |
| 2026-10-06 12:00 |
17:51:02.22 |
-53:52:59.1 |
HIP 87386 |
4.38 |
| 2026-10-07 00:00 |
17:51:04.63 |
-53:52:27.5 |
HIP 87386 |
3.78 |
| 2026-10-07 12:00 |
17:51:07.08 |
-53:51:56.0 |
HIP 87386 |
3.19 |
| 2026-10-08 00:00 |
17:51:09.60 |
-53:51:24.6 |
HIP 87386 |
2.62 |
| 2026-10-08 12:00 |
17:51:12.17 |
-53:50:53.4 |
HIP 87386 |
2.09 |
| 2026-10-09 00:00 |
17:51:14.79 |
-53:50:22.2 |
HIP 87386 |
1.62 |
| 2026-10-09 12:00 |
17:51:17.48 |
-53:49:51.1 |
HIP 87386 |
1.31 |
| 2026-10-10 00:00 |
17:51:20.21 |
-53:49:20.1 |
HIP 87386 |
1.28 |
| 2026-10-10 12:00 |
17:51:23.01 |
-53:48:49.3 |
HIP 87386 |
1.55 |
| 2026-10-11 00:00 |
17:51:25.86 |
-53:48:18.5 |
HIP 87386 |
2.01 |