| 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) |
| 2026-07-29 00:00 |
17:55:07.54 |
-55:04:35.7 |
HIP 87892 |
25.59 |
| 2026-07-29 12:00 |
17:55:01.98 |
-55:04:13.3 |
HIP 87892 |
26.42 |
| 2026-07-30 00:00 |
17:54:56.46 |
-55:03:50.6 |
HIP 87510 |
26.64 |
| 2026-07-30 12:00 |
17:54:50.98 |
-55:03:27.7 |
HIP 87510 |
26.38 |
| 2026-07-31 00:00 |
17:54:45.55 |
-55:03:04.6 |
HIP 87510 |
26.16 |
| 2026-07-31 12:00 |
17:54:40.17 |
-55:02:41.2 |
HIP 87510 |
25.97 |
| 2026-08-01 00:00 |
17:54:34.82 |
-55:02:17.6 |
HIP 87510 |
25.81 |
| 2026-08-01 12:00 |
17:54:29.53 |
-55:01:53.8 |
HIP 87510 |
25.69 |
| 2026-08-02 00:00 |
17:54:24.27 |
-55:01:29.8 |
HIP 87510 |
25.60 |
| 2026-08-02 12:00 |
17:54:19.07 |
-55:01:05.5 |
HIP 87510 |
25.55 |
| 2026-08-03 00:00 |
17:54:13.91 |
-55:00:41.1 |
HIP 87510 |
25.53 |
| 2026-08-03 12:00 |
17:54:08.79 |
-55:00:16.4 |
HIP 87510 |
25.55 |
| 2026-08-04 00:00 |
17:54:03.72 |
-54:59:51.5 |
HIP 87510 |
25.59 |
| 2026-08-04 12:00 |
17:53:58.70 |
-54:59:26.4 |
HIP 87510 |
25.68 |
| 2026-08-05 00:00 |
17:53:53.73 |
-54:59:01.1 |
HIP 87510 |
25.79 |
| 2026-08-05 12:00 |
17:53:48.80 |
-54:58:35.6 |
HIP 87510 |
25.93 |
| 2026-08-06 00:00 |
17:53:43.92 |
-54:58:09.9 |
HIP 87510 |
26.11 |
| 2026-08-06 12:00 |
17:53:39.09 |
-54:57:44.0 |
HIP 87346 |
25.80 |
| 2026-08-07 00:00 |
17:53:34.31 |
-54:57:17.9 |
HIP 87346 |
25.00 |
| 2026-08-07 12:00 |
17:53:29.58 |
-54:56:51.6 |
HIP 87346 |
24.21 |
| 2026-08-08 00:00 |
17:53:24.90 |
-54:56:25.2 |
HIP 87346 |
23.43 |
| 2026-08-08 12:00 |
17:53:20.27 |
-54:55:58.5 |
HIP 87346 |
22.65 |
| 2026-08-09 00:00 |
17:53:15.69 |
-54:55:31.6 |
HIP 87346 |
21.88 |
| 2026-08-09 12:00 |
17:53:11.16 |
-54:55:04.5 |
HIP 87346 |
21.12 |
| 2026-08-10 00:00 |
17:53:06.68 |
-54:54:37.3 |
HIP 87346 |
20.36 |
| 2026-08-10 12:00 |
17:53:02.26 |
-54:54:09.9 |
HIP 87346 |
19.62 |
| 2026-08-11 00:00 |
17:52:57.88 |
-54:53:42.3 |
HIP 87346 |
18.88 |
| 2026-08-11 12:00 |
17:52:53.56 |
-54:53:14.5 |
HIP 87346 |
18.15 |
| 2026-08-12 00:00 |
17:52:49.29 |
-54:52:46.6 |
HIP 87346 |
17.44 |
| 2026-08-12 12:00 |
17:52:45.08 |
-54:52:18.4 |
HIP 87346 |
16.73 |
| 2026-08-13 00:00 |
17:52:40.92 |
-54:51:50.1 |
HIP 87346 |
16.04 |
| 2026-08-13 12:00 |
17:52:36.81 |
-54:51:21.7 |
HIP 87346 |
15.36 |
| 2026-08-14 00:00 |
17:52:32.75 |
-54:50:53.1 |
HIP 87346 |
14.69 |
| 2026-08-14 12:00 |
17:52:28.75 |
-54:50:24.3 |
HIP 87346 |
14.04 |
| 2026-08-15 00:00 |
17:52:24.81 |
-54:49:55.3 |
HIP 87346 |
13.41 |
| 2026-08-15 12:00 |
17:52:20.92 |
-54:49:26.2 |
HIP 87346 |
12.80 |
| 2026-08-16 00:00 |
17:52:17.08 |
-54:48:57.0 |
HIP 87346 |
12.21 |
| 2026-08-16 12:00 |
17:52:13.30 |
-54:48:27.6 |
HIP 87346 |
11.65 |
| 2026-08-17 00:00 |
17:52:09.58 |
-54:47:58.0 |
HIP 87346 |
11.11 |
| 2026-08-17 12:00 |
17:52:05.91 |
-54:47:28.4 |
HIP 87346 |
10.60 |
| 2026-08-18 00:00 |
17:52:02.30 |
-54:46:58.5 |
HIP 87346 |
10.13 |
| 2026-08-18 12:00 |
17:51:58.75 |
-54:46:28.5 |
HIP 87346 |
9.69 |
| 2026-08-19 00:00 |
17:51:55.25 |
-54:45:58.4 |
HIP 87346 |
9.30 |