| 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) |
| 2026-03-26 00:00 |
06:03:03.79 |
+12:18:02.7 |
HIP 28673 |
19.22 |
| 2026-03-26 12:00 |
06:03:04.47 |
+12:18:17.8 |
HIP 28673 |
18.95 |
| 2026-03-27 00:00 |
06:03:05.19 |
+12:18:32.8 |
HIP 28673 |
18.68 |
| 2026-03-27 12:00 |
06:03:05.95 |
+12:18:47.9 |
HIP 28673 |
18.40 |
| 2026-03-28 00:00 |
06:03:06.76 |
+12:19:02.9 |
HIP 28673 |
18.13 |
| 2026-03-28 12:00 |
06:03:07.61 |
+12:19:17.8 |
HIP 28673 |
17.86 |
| 2026-03-29 00:00 |
06:03:08.50 |
+12:19:32.8 |
HIP 28673 |
17.59 |
| 2026-03-29 12:00 |
06:03:09.44 |
+12:19:47.7 |
HIP 28673 |
17.32 |
| 2026-03-30 00:00 |
06:03:10.42 |
+12:20:02.6 |
HIP 28673 |
17.06 |
| 2026-03-30 12:00 |
06:03:11.44 |
+12:20:17.4 |
HIP 28673 |
16.80 |
| 2026-03-31 00:00 |
06:03:12.50 |
+12:20:32.2 |
HIP 28673 |
16.54 |
| 2026-03-31 12:00 |
06:03:13.61 |
+12:20:46.9 |
HIP 28673 |
16.28 |
| 2026-04-01 00:00 |
06:03:14.75 |
+12:21:01.7 |
HIP 28673 |
16.03 |
| 2026-04-01 12:00 |
06:03:15.94 |
+12:21:16.4 |
HIP 28673 |
15.79 |
| 2026-04-02 00:00 |
06:03:17.17 |
+12:21:31.0 |
HIP 28673 |
15.55 |
| 2026-04-02 12:00 |
06:03:18.44 |
+12:21:45.6 |
HIP 28673 |
15.32 |
| 2026-04-03 00:00 |
06:03:19.76 |
+12:22:00.2 |
HIP 28673 |
15.10 |
| 2026-04-03 12:00 |
06:03:21.11 |
+12:22:14.7 |
HIP 28673 |
14.89 |
| 2026-04-04 00:00 |
06:03:22.51 |
+12:22:29.2 |
HIP 28673 |
14.69 |
| 2026-04-04 12:00 |
06:03:23.95 |
+12:22:43.6 |
HIP 28673 |
14.49 |
| 2026-04-05 00:00 |
06:03:25.43 |
+12:22:58.0 |
HIP 28673 |
14.32 |
| 2026-04-05 12:00 |
06:03:26.95 |
+12:23:12.3 |
HIP 28673 |
14.15 |
| 2026-04-06 00:00 |
06:03:28.51 |
+12:23:26.6 |
HIP 28673 |
14.00 |
| 2026-04-06 12:00 |
06:03:30.11 |
+12:23:40.9 |
HIP 28673 |
13.87 |
| 2026-04-07 00:00 |
06:03:31.75 |
+12:23:55.1 |
HIP 28673 |
13.75 |
| 2026-04-07 12:00 |
06:03:33.43 |
+12:24:09.2 |
HIP 28673 |
13.65 |
| 2026-04-08 00:00 |
06:03:35.16 |
+12:24:23.3 |
HIP 28673 |
13.58 |
| 2026-04-08 12:00 |
06:03:36.92 |
+12:24:37.4 |
HIP 28673 |
13.52 |
| 2026-04-09 00:00 |
06:03:38.72 |
+12:24:51.3 |
HIP 28673 |
13.49 |
| 2026-04-09 12:00 |
06:03:40.56 |
+12:25:05.3 |
HIP 28673 |
13.48 |
| 2026-04-10 00:00 |
06:03:42.44 |
+12:25:19.2 |
HIP 28673 |
13.49 |
| 2026-04-10 12:00 |
06:03:44.37 |
+12:25:33.0 |
HIP 28673 |
13.54 |
| 2026-04-11 00:00 |
06:03:46.33 |
+12:25:46.8 |
HIP 28673 |
13.60 |
| 2026-04-11 12:00 |
06:03:48.33 |
+12:26:00.5 |
HIP 28673 |
13.69 |
| 2026-04-12 00:00 |
06:03:50.36 |
+12:26:14.2 |
HIP 28673 |
13.82 |
| 2026-04-12 12:00 |
06:03:52.44 |
+12:26:27.7 |
HIP 28673 |
13.96 |
| 2026-04-13 00:00 |
06:03:54.56 |
+12:26:41.3 |
HIP 28673 |
14.14 |
| 2026-04-13 12:00 |
06:03:56.71 |
+12:26:54.8 |
HIP 28673 |
14.34 |
| 2026-04-14 00:00 |
06:03:58.90 |
+12:27:08.2 |
HIP 28673 |
14.57 |
| 2026-04-14 12:00 |
06:04:01.14 |
+12:27:21.5 |
HIP 28673 |
14.83 |
| 2026-04-15 00:00 |
06:04:03.40 |
+12:27:34.8 |
HIP 28673 |
15.11 |
| 2026-04-15 12:00 |
06:04:05.71 |
+12:27:48.1 |
HIP 28673 |
15.42 |
| 2026-04-16 00:00 |
06:04:08.05 |
+12:28:01.2 |
HIP 28673 |
15.75 |