| 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) |
| 2026-05-12 00:00 |
06:06:55.85 |
+12:37:36.0 |
HIP 28894 |
16.06 |
| 2026-05-12 12:00 |
06:06:59.84 |
+12:37:44.7 |
HIP 28894 |
16.96 |
| 2026-05-13 00:00 |
06:07:03.86 |
+12:37:53.2 |
HIP 28894 |
17.87 |
| 2026-05-13 12:00 |
06:07:07.90 |
+12:38:01.7 |
HIP 28894 |
18.80 |
| 2026-05-14 00:00 |
06:07:11.97 |
+12:38:10.0 |
HIP 28894 |
19.73 |
| 2026-05-14 12:00 |
06:07:16.06 |
+12:38:18.3 |
HIP 28894 |
20.68 |
| 2026-05-15 00:00 |
06:07:20.17 |
+12:38:26.4 |
HIP 28894 |
21.63 |
| 2026-05-15 12:00 |
06:07:24.31 |
+12:38:34.4 |
HIP 28894 |
22.60 |
| 2026-05-16 00:00 |
06:07:28.47 |
+12:38:42.4 |
HIP 28894 |
23.57 |
| 2026-05-16 12:00 |
06:07:32.65 |
+12:38:50.2 |
HIP 29146 |
22.97 |
| 2026-05-17 00:00 |
06:07:36.86 |
+12:38:57.9 |
HIP 29146 |
22.13 |
| 2026-05-17 12:00 |
06:07:41.09 |
+12:39:05.5 |
HIP 29146 |
21.31 |
| 2026-05-18 00:00 |
06:07:45.34 |
+12:39:13.0 |
HIP 29146 |
20.50 |
| 2026-05-18 12:00 |
06:07:49.61 |
+12:39:20.4 |
HIP 29146 |
19.70 |
| 2026-05-19 00:00 |
06:07:53.90 |
+12:39:27.7 |
HIP 29146 |
18.93 |
| 2026-05-19 12:00 |
06:07:58.21 |
+12:39:34.9 |
HIP 29146 |
18.18 |
| 2026-05-20 00:00 |
06:08:02.54 |
+12:39:42.0 |
HIP 29146 |
17.45 |
| 2026-05-20 12:00 |
06:08:06.89 |
+12:39:49.0 |
HIP 29146 |
16.76 |
| 2026-05-21 00:00 |
06:08:11.26 |
+12:39:55.8 |
HIP 29146 |
16.10 |
| 2026-05-21 12:00 |
06:08:15.66 |
+12:40:02.6 |
HIP 29146 |
15.49 |
| 2026-05-22 00:00 |
06:08:20.07 |
+12:40:09.2 |
HIP 29146 |
14.92 |
| 2026-05-22 12:00 |
06:08:24.50 |
+12:40:15.8 |
HIP 29146 |
14.41 |
| 2026-05-23 00:00 |
06:08:28.94 |
+12:40:22.2 |
HIP 29146 |
13.97 |
| 2026-05-23 12:00 |
06:08:33.41 |
+12:40:28.5 |
HIP 29146 |
13.59 |
| 2026-05-24 00:00 |
06:08:37.89 |
+12:40:34.7 |
HIP 29146 |
13.29 |
| 2026-05-24 12:00 |
06:08:42.40 |
+12:40:40.8 |
HIP 29146 |
13.07 |
| 2026-05-25 00:00 |
06:08:46.92 |
+12:40:46.8 |
HIP 29146 |
12.93 |
| 2026-05-25 12:00 |
06:08:51.45 |
+12:40:52.7 |
HIP 29146 |
12.89 |
| 2026-05-26 00:00 |
06:08:56.00 |
+12:40:58.4 |
HIP 29146 |
12.95 |
| 2026-05-26 12:00 |
06:09:00.57 |
+12:41:04.1 |
HIP 29146 |
13.10 |
| 2026-05-27 00:00 |
06:09:05.16 |
+12:41:09.6 |
HIP 29146 |
13.34 |
| 2026-05-27 12:00 |
06:09:09.76 |
+12:41:15.0 |
HIP 29146 |
13.66 |
| 2026-05-28 00:00 |
06:09:14.38 |
+12:41:20.4 |
HIP 29146 |
14.07 |
| 2026-05-28 12:00 |
06:09:19.01 |
+12:41:25.6 |
HIP 29146 |
14.56 |
| 2026-05-29 00:00 |
06:09:23.66 |
+12:41:30.7 |
HIP 29146 |
15.11 |
| 2026-05-29 12:00 |
06:09:28.32 |
+12:41:35.6 |
HIP 29146 |
15.73 |
| 2026-05-30 00:00 |
06:09:33.00 |
+12:41:40.5 |
HIP 29146 |
16.41 |
| 2026-05-30 12:00 |
06:09:37.69 |
+12:41:45.3 |
HIP 29146 |
17.13 |
| 2026-05-31 00:00 |
06:09:42.40 |
+12:41:49.9 |
HIP 29146 |
17.90 |
| 2026-05-31 12:00 |
06:09:47.12 |
+12:41:54.4 |
HIP 29146 |
18.71 |
| 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 |