| Parameter |
Value |
| Designation |
C/2017 E1 (Borisov) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-04-10T03:19:38.262720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:31Z |
| Obs used |
183 |
| NEO |
- |
| M1 |
14.000 |
| K1 |
32.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-03-16.0000000 |
| e |
1.00257425 |
| q (au) |
0.900663 |
| a (au) |
-349.874391 |
| i (deg) |
14.554152 |
| Ω (om, deg) |
142.732826 |
| ω (w, deg) |
152.473457 |
| M (ma, deg) |
-0.003786 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.076 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.076 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
| 2017-03-01 |
2017-04-09 |
+33.3745 |
-1.729 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
06:09:51.85 |
+12:41:58.9 |
HIP 29146 |
19.56 |
| 2026-06-01 12:00 |
06:09:56.59 |
+12:42:03.2 |
HIP 29146 |
20.43 |
| 2026-06-02 00:00 |
06:10:01.35 |
+12:42:07.4 |
HIP 29146 |
21.34 |
| 2026-06-02 12:00 |
06:10:06.12 |
+12:42:11.4 |
HIP 29146 |
22.27 |
| 2026-06-03 00:00 |
06:10:10.91 |
+12:42:15.4 |
HIP 29146 |
23.22 |
| 2026-06-03 12:00 |
06:10:15.70 |
+12:42:19.3 |
HIP 29146 |
24.19 |
| 2026-06-04 00:00 |
06:10:20.51 |
+12:42:23.0 |
HIP 29146 |
25.18 |
| 2026-06-04 12:00 |
06:10:25.33 |
+12:42:26.6 |
HIP 29146 |
26.19 |
| 2026-06-05 00:00 |
06:10:30.16 |
+12:42:30.1 |
HIP 29146 |
27.22 |
| 2026-06-05 12:00 |
06:10:35.00 |
+12:42:33.5 |
HIP 29146 |
28.25 |
| 2026-06-06 00:00 |
06:10:39.85 |
+12:42:36.8 |
HIP 29146 |
29.30 |
| 2026-06-06 12:00 |
06:10:44.72 |
+12:42:40.0 |
HIP 29146 |
30.36 |
| 2026-06-07 00:00 |
06:10:49.59 |
+12:42:43.0 |
HIP 29146 |
31.43 |
| 2026-06-07 12:00 |
06:10:54.47 |
+12:42:45.9 |
HIP 29146 |
32.51 |
| 2026-06-08 00:00 |
06:10:59.36 |
+12:42:48.7 |
HIP 29184 |
33.48 |
| 2026-06-08 12:00 |
06:11:04.26 |
+12:42:51.4 |
HIP 29184 |
34.29 |
| 2026-06-09 00:00 |
06:11:09.17 |
+12:42:54.0 |
HIP 29184 |
35.13 |
| 2026-06-09 12:00 |
06:11:14.09 |
+12:42:56.5 |
HIP 29493 |
35.44 |
| 2026-06-10 00:00 |
06:11:19.02 |
+12:42:58.9 |
HIP 29493 |
34.60 |
| 2026-06-10 12:00 |
06:11:23.96 |
+12:43:01.1 |
HIP 29493 |
33.78 |
| 2026-06-11 00:00 |
06:11:28.90 |
+12:43:03.2 |
HIP 29493 |
32.98 |
| 2026-06-11 12:00 |
06:11:33.85 |
+12:43:05.2 |
HIP 29493 |
32.20 |
| 2026-06-12 00:00 |
06:11:38.81 |
+12:43:07.1 |
HIP 29493 |
31.46 |
| 2026-06-12 12:00 |
06:11:43.78 |
+12:43:08.9 |
HIP 29493 |
30.75 |
| 2026-06-13 00:00 |
06:11:48.75 |
+12:43:10.5 |
HIP 29493 |
30.06 |
| 2026-06-13 12:00 |
06:11:53.73 |
+12:43:12.0 |
HIP 29493 |
29.42 |
| 2026-06-14 00:00 |
06:11:58.71 |
+12:43:13.5 |
HIP 29493 |
28.81 |
| 2026-06-14 12:00 |
06:12:03.70 |
+12:43:14.7 |
HIP 29493 |
28.24 |
| 2026-06-15 00:00 |
06:12:08.69 |
+12:43:15.9 |
HIP 29493 |
27.71 |
| 2026-06-15 12:00 |
06:12:13.69 |
+12:43:17.0 |
HIP 29493 |
27.23 |
| 2026-06-16 00:00 |
06:12:18.70 |
+12:43:17.9 |
HIP 29493 |
26.80 |
| 2026-06-16 12:00 |
06:12:23.71 |
+12:43:18.8 |
HIP 29493 |
26.42 |
| 2026-06-17 00:00 |
06:12:28.72 |
+12:43:19.5 |
HIP 29493 |
26.10 |
| 2026-06-17 12:00 |
06:12:33.74 |
+12:43:20.1 |
HIP 29493 |
25.82 |
| 2026-06-18 00:00 |
06:12:38.76 |
+12:43:20.5 |
HIP 29493 |
25.61 |
| 2026-06-18 12:00 |
06:12:43.78 |
+12:43:20.9 |
HIP 29493 |
25.45 |
| 2026-06-19 00:00 |
06:12:48.81 |
+12:43:21.1 |
HIP 29493 |
25.36 |
| 2026-06-19 12:00 |
06:12:53.84 |
+12:43:21.3 |
HIP 29493 |
25.32 |
| 2026-06-20 00:00 |
06:12:58.87 |
+12:43:21.3 |
HIP 29493 |
25.35 |
| 2026-06-20 12:00 |
06:13:03.90 |
+12:43:21.1 |
HIP 29493 |
25.44 |
| 2026-06-21 00:00 |
06:13:08.93 |
+12:43:20.9 |
HIP 29493 |
25.58 |
| 2026-06-21 12:00 |
06:13:13.97 |
+12:43:20.6 |
HIP 29630 |
25.01 |
| 2026-06-22 00:00 |
06:13:19.00 |
+12:43:20.1 |
HIP 29630 |
24.02 |