| 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 |
-1.000 |
| 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) |
| 2026-05-12 00:00 |
08:11:38.23 |
+82:36:43.8 |
HIP 41208 |
27.46 |
| 2026-05-12 12:00 |
08:11:49.68 |
+82:35:44.4 |
HIP 41208 |
26.76 |
| 2026-05-13 00:00 |
08:12:01.34 |
+82:34:45.1 |
HIP 41208 |
26.08 |
| 2026-05-13 12:00 |
08:12:13.21 |
+82:33:46.0 |
HIP 41208 |
25.42 |
| 2026-05-14 00:00 |
08:12:25.27 |
+82:32:47.0 |
HIP 41208 |
24.77 |
| 2026-05-14 12:00 |
08:12:37.54 |
+82:31:48.1 |
HIP 41208 |
24.15 |
| 2026-05-15 00:00 |
08:12:50.00 |
+82:30:49.4 |
HIP 41208 |
23.56 |
| 2026-05-15 12:00 |
08:13:02.66 |
+82:29:50.8 |
HIP 41208 |
22.98 |
| 2026-05-16 00:00 |
08:13:15.52 |
+82:28:52.3 |
HIP 41208 |
22.44 |
| 2026-05-16 12:00 |
08:13:28.56 |
+82:27:54.0 |
HIP 41208 |
21.93 |
| 2026-05-17 00:00 |
08:13:41.80 |
+82:26:55.8 |
HIP 41208 |
21.45 |
| 2026-05-17 12:00 |
08:13:55.22 |
+82:25:57.8 |
HIP 41208 |
21.00 |
| 2026-05-18 00:00 |
08:14:08.83 |
+82:25:00.0 |
HIP 41208 |
20.59 |
| 2026-05-18 12:00 |
08:14:22.62 |
+82:24:02.2 |
HIP 41208 |
20.22 |
| 2026-05-19 00:00 |
08:14:36.59 |
+82:23:04.7 |
HIP 41208 |
19.90 |
| 2026-05-19 12:00 |
08:14:50.74 |
+82:22:07.3 |
HIP 41208 |
19.61 |
| 2026-05-20 00:00 |
08:15:05.06 |
+82:21:10.1 |
HIP 41208 |
19.37 |
| 2026-05-20 12:00 |
08:15:19.56 |
+82:20:13.0 |
HIP 41208 |
19.18 |
| 2026-05-21 00:00 |
08:15:34.23 |
+82:19:16.1 |
HIP 41208 |
19.04 |
| 2026-05-21 12:00 |
08:15:49.07 |
+82:18:19.4 |
HIP 41208 |
18.96 |
| 2026-05-22 00:00 |
08:16:04.08 |
+82:17:22.8 |
HIP 41208 |
18.92 |
| 2026-05-22 12:00 |
08:16:19.26 |
+82:16:26.4 |
HIP 41208 |
18.93 |
| 2026-05-23 00:00 |
08:16:34.60 |
+82:15:30.2 |
HIP 41208 |
19.00 |
| 2026-05-23 12:00 |
08:16:50.10 |
+82:14:34.2 |
HIP 41208 |
19.12 |
| 2026-05-24 00:00 |
08:17:05.76 |
+82:13:38.4 |
HIP 41208 |
19.28 |
| 2026-05-24 12:00 |
08:17:21.57 |
+82:12:42.7 |
HIP 41208 |
19.50 |
| 2026-05-25 00:00 |
08:17:37.55 |
+82:11:47.2 |
HIP 41208 |
19.77 |
| 2026-05-25 12:00 |
08:17:53.67 |
+82:10:51.9 |
HIP 41208 |
20.08 |
| 2026-05-26 00:00 |
08:18:09.95 |
+82:09:56.8 |
HIP 41208 |
20.44 |
| 2026-05-26 12:00 |
08:18:26.38 |
+82:09:01.9 |
HIP 41208 |
20.83 |
| 2026-05-27 00:00 |
08:18:42.96 |
+82:08:07.2 |
HIP 41208 |
21.27 |
| 2026-05-27 12:00 |
08:18:59.68 |
+82:07:12.7 |
HIP 41208 |
21.75 |
| 2026-05-28 00:00 |
08:19:16.55 |
+82:06:18.3 |
HIP 41208 |
22.25 |
| 2026-05-28 12:00 |
08:19:33.56 |
+82:05:24.2 |
HIP 41208 |
22.80 |
| 2026-05-29 00:00 |
08:19:50.71 |
+82:04:30.2 |
HIP 40288 |
23.12 |
| 2026-05-29 12:00 |
08:20:08.00 |
+82:03:36.5 |
HIP 40288 |
22.75 |
| 2026-05-30 00:00 |
08:20:25.43 |
+82:02:43.0 |
HIP 40288 |
22.45 |
| 2026-05-30 12:00 |
08:20:42.99 |
+82:01:49.6 |
HIP 40288 |
22.19 |
| 2026-05-31 00:00 |
08:21:00.69 |
+82:00:56.5 |
HIP 40288 |
22.00 |
| 2026-05-31 12:00 |
08:21:18.53 |
+82:00:03.6 |
HIP 40288 |
21.86 |
| 2026-06-01 00:00 |
08:21:36.49 |
+81:59:10.9 |
HIP 40288 |
21.79 |
| 2026-06-01 12:00 |
08:21:54.59 |
+81:58:18.4 |
HIP 40288 |
21.77 |
| 2026-06-02 00:00 |
08:22:12.81 |
+81:57:26.1 |
HIP 40288 |
21.82 |