| Parameter |
Value |
| Designation |
C/2015 D4 (Borisov) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-10-28T05:41:47.852160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:07Z |
| Obs used |
51 |
| NEO |
- |
| M1 |
9.200 |
| K1 |
16.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-03-30.0000000 |
| e |
0.98906756 |
| q (au) |
0.861677 |
| a (au) |
78.818308 |
| i (deg) |
77.301723 |
| Ω (om, deg) |
305.810298 |
| ω (w, deg) |
314.694165 |
| M (ma, deg) |
0.215169 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.234 + 5.834\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.234 |
| n |
5.834 |
| gf |
1.000 |
| gb |
-0.503 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
09:47:05.90 |
+80:51:26.1 |
HIP 47028 |
30.21 |
| 2026-09-20 12:00 |
09:47:26.60 |
+80:51:49.4 |
HIP 47028 |
31.11 |
| 2026-09-21 00:00 |
09:47:47.22 |
+80:52:13.2 |
HIP 47028 |
32.00 |
| 2026-09-21 12:00 |
09:48:07.76 |
+80:52:37.3 |
HIP 47028 |
32.90 |
| 2026-09-22 00:00 |
09:48:28.20 |
+80:53:01.9 |
HIP 47028 |
33.79 |
| 2026-09-22 12:00 |
09:48:48.56 |
+80:53:26.8 |
HIP 47028 |
34.68 |
| 2026-09-23 00:00 |
09:49:08.82 |
+80:53:52.1 |
HIP 47028 |
35.57 |
| 2026-09-23 12:00 |
09:49:29.00 |
+80:54:17.9 |
HIP 47028 |
36.45 |
| 2026-09-24 00:00 |
09:49:49.09 |
+80:54:44.0 |
HIP 47028 |
37.34 |
| 2026-09-24 12:00 |
09:50:09.08 |
+80:55:10.5 |
HIP 47028 |
38.22 |
| 2026-09-25 00:00 |
09:50:28.98 |
+80:55:37.3 |
HIP 48938 |
38.94 |
| 2026-09-25 12:00 |
09:50:48.78 |
+80:56:04.6 |
HIP 48938 |
38.90 |
| 2026-09-26 00:00 |
09:51:08.49 |
+80:56:32.3 |
HIP 48938 |
38.88 |
| 2026-09-26 12:00 |
09:51:28.11 |
+80:57:00.3 |
HIP 48938 |
38.90 |
| 2026-09-27 00:00 |
09:51:47.62 |
+80:57:28.8 |
HIP 48938 |
38.95 |
| 2026-09-27 12:00 |
09:52:07.04 |
+80:57:57.6 |
HIP 48938 |
39.03 |
| 2026-09-28 00:00 |
09:52:26.36 |
+80:58:26.8 |
HIP 48938 |
39.13 |
| 2026-09-28 12:00 |
09:52:45.59 |
+80:58:56.4 |
HIP 48938 |
39.27 |
| 2026-09-29 00:00 |
09:53:04.71 |
+80:59:26.4 |
HIP 48938 |
39.44 |
| 2026-09-29 12:00 |
09:53:23.72 |
+80:59:56.7 |
HIP 48938 |
39.63 |
| 2026-09-30 00:00 |
09:53:42.64 |
+81:00:27.5 |
HIP 48938 |
39.85 |
| 2026-09-30 12:00 |
09:54:01.45 |
+81:00:58.6 |
HIP 48938 |
40.10 |
| 2026-10-01 00:00 |
09:54:20.16 |
+81:01:30.1 |
HIP 49059 |
40.34 |
| 2026-10-01 12:00 |
09:54:38.76 |
+81:02:01.9 |
HIP 49059 |
40.56 |
| 2026-10-02 00:00 |
09:54:57.25 |
+81:02:34.2 |
HIP 47807 |
40.58 |
| 2026-10-02 12:00 |
09:55:15.63 |
+81:03:06.8 |
HIP 47807 |
40.53 |
| 2026-10-03 00:00 |
09:55:33.91 |
+81:03:39.9 |
HIP 47807 |
40.49 |
| 2026-10-03 12:00 |
09:55:52.07 |
+81:04:13.3 |
HIP 47807 |
40.46 |
| 2026-10-04 00:00 |
09:56:10.12 |
+81:04:47.0 |
HIP 47807 |
40.44 |
| 2026-10-04 12:00 |
09:56:28.06 |
+81:05:21.2 |
HIP 47807 |
40.43 |
| 2026-10-05 00:00 |
09:56:45.88 |
+81:05:55.7 |
HIP 47807 |
40.43 |
| 2026-10-05 12:00 |
09:57:03.59 |
+81:06:30.6 |
HIP 47807 |
40.45 |
| 2026-10-06 00:00 |
09:57:21.18 |
+81:07:05.8 |
HIP 47807 |
40.47 |
| 2026-10-06 12:00 |
09:57:38.65 |
+81:07:41.5 |
HIP 47807 |
40.50 |
| 2026-10-07 00:00 |
09:57:56.00 |
+81:08:17.5 |
HIP 47807 |
40.55 |
| 2026-10-07 12:00 |
09:58:13.22 |
+81:08:53.9 |
HIP 47807 |
40.60 |
| 2026-10-08 00:00 |
09:58:30.33 |
+81:09:30.6 |
HIP 47807 |
40.67 |
| 2026-10-08 12:00 |
09:58:47.31 |
+81:10:07.7 |
HIP 47807 |
40.75 |
| 2026-10-09 00:00 |
09:59:04.16 |
+81:10:45.2 |
HIP 47807 |
40.83 |
| 2026-10-09 12:00 |
09:59:20.89 |
+81:11:23.0 |
HIP 47807 |
40.93 |
| 2026-10-10 00:00 |
09:59:37.49 |
+81:12:01.2 |
HIP 47807 |
41.04 |
| 2026-10-10 12:00 |
09:59:53.96 |
+81:12:39.8 |
HIP 47807 |
41.15 |
| 2026-10-11 00:00 |
10:00:10.30 |
+81:13:18.7 |
HIP 47807 |
41.28 |