| Parameter |
Value |
| Designation |
C/2019 Q4 (Borisov) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-12-08T13:16:05.885760Z |
| Orbit solution date (soln_date, UTC) |
2024-06-24T15:49:04Z |
| Obs used |
964 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-08-30T01:03:19.872000Z |
| Discovery magnitude (MPC) |
17.80 R |
| Discovery observatory (MPC) |
L51 · MARGO, Nauchnyi |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-01-05.0000000 |
| e |
3.35647578 |
| q (au) |
2.006521 |
| a (au) |
-0.851492 |
| i (deg) |
44.052642 |
| Ω (om, deg) |
308.147729 |
| ω (w, deg) |
209.123686 |
| M (ma, deg) |
34.429470 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.853 + 2.256\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.853 |
| n |
2.256 |
| gf |
1.000 |
| gb |
-0.706 |
| 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 |
| 2018-12-13 |
2019-12-08 |
+1.5408 |
-0.661 |
| 2019-12-08 |
2020-03-05 |
+1.5873 |
-0.696 |
| 2020-03-05 |
2020-09-30 |
+12.2394 |
-6.131 |
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 |
18:11:40.95 |
-54:00:53.9 |
HIP 89125 |
14.48 |
| 2026-03-26 12:00 |
18:11:40.95 |
-54:01:12.5 |
HIP 89125 |
14.17 |
| 2026-03-27 00:00 |
18:11:40.91 |
-54:01:31.1 |
HIP 89125 |
13.87 |
| 2026-03-27 12:00 |
18:11:40.84 |
-54:01:49.8 |
HIP 89125 |
13.56 |
| 2026-03-28 00:00 |
18:11:40.72 |
-54:02:08.4 |
HIP 89125 |
13.25 |
| 2026-03-28 12:00 |
18:11:40.57 |
-54:02:27.0 |
HIP 89125 |
12.94 |
| 2026-03-29 00:00 |
18:11:40.38 |
-54:02:45.5 |
HIP 89125 |
12.64 |
| 2026-03-29 12:00 |
18:11:40.15 |
-54:03:04.1 |
HIP 89125 |
12.33 |
| 2026-03-30 00:00 |
18:11:39.88 |
-54:03:22.7 |
HIP 89125 |
12.01 |
| 2026-03-30 12:00 |
18:11:39.57 |
-54:03:41.2 |
HIP 89125 |
11.70 |
| 2026-03-31 00:00 |
18:11:39.23 |
-54:03:59.7 |
HIP 89125 |
11.39 |
| 2026-03-31 12:00 |
18:11:38.85 |
-54:04:18.2 |
HIP 89125 |
11.08 |
| 2026-04-01 00:00 |
18:11:38.43 |
-54:04:36.7 |
HIP 89125 |
10.76 |
| 2026-04-01 12:00 |
18:11:37.97 |
-54:04:55.2 |
HIP 89125 |
10.45 |
| 2026-04-02 00:00 |
18:11:37.47 |
-54:05:13.6 |
HIP 89125 |
10.13 |
| 2026-04-02 12:00 |
18:11:36.94 |
-54:05:32.1 |
HIP 89125 |
9.82 |
| 2026-04-03 00:00 |
18:11:36.36 |
-54:05:50.5 |
HIP 89125 |
9.50 |
| 2026-04-03 12:00 |
18:11:35.75 |
-54:06:08.8 |
HIP 89125 |
9.18 |
| 2026-04-04 00:00 |
18:11:35.10 |
-54:06:27.2 |
HIP 89125 |
8.86 |
| 2026-04-04 12:00 |
18:11:34.42 |
-54:06:45.5 |
HIP 89125 |
8.54 |
| 2026-04-05 00:00 |
18:11:33.69 |
-54:07:03.8 |
HIP 89125 |
8.22 |
| 2026-04-05 12:00 |
18:11:32.93 |
-54:07:22.0 |
HIP 89125 |
7.90 |
| 2026-04-06 00:00 |
18:11:32.13 |
-54:07:40.2 |
HIP 89125 |
7.58 |
| 2026-04-06 12:00 |
18:11:31.30 |
-54:07:58.4 |
HIP 89125 |
7.26 |
| 2026-04-07 00:00 |
18:11:30.42 |
-54:08:16.5 |
HIP 89125 |
6.94 |
| 2026-04-07 12:00 |
18:11:29.51 |
-54:08:34.6 |
HIP 89125 |
6.62 |
| 2026-04-08 00:00 |
18:11:28.56 |
-54:08:52.7 |
HIP 89125 |
6.31 |
| 2026-04-08 12:00 |
18:11:27.58 |
-54:09:10.7 |
HIP 89125 |
5.99 |
| 2026-04-09 00:00 |
18:11:26.56 |
-54:09:28.7 |
HIP 89125 |
5.67 |
| 2026-04-09 12:00 |
18:11:25.50 |
-54:09:46.6 |
HIP 89125 |
5.36 |
| 2026-04-10 00:00 |
18:11:24.40 |
-54:10:04.5 |
HIP 89125 |
5.05 |
| 2026-04-10 12:00 |
18:11:23.27 |
-54:10:22.4 |
HIP 89125 |
4.75 |
| 2026-04-11 00:00 |
18:11:22.09 |
-54:10:40.2 |
HIP 89125 |
4.45 |
| 2026-04-11 12:00 |
18:11:20.89 |
-54:10:57.9 |
HIP 89125 |
4.16 |
| 2026-04-12 00:00 |
18:11:19.64 |
-54:11:15.6 |
HIP 89125 |
3.89 |
| 2026-04-12 12:00 |
18:11:18.36 |
-54:11:33.2 |
HIP 89125 |
3.62 |
| 2026-04-13 00:00 |
18:11:17.05 |
-54:11:50.8 |
HIP 89125 |
3.37 |
| 2026-04-13 12:00 |
18:11:15.69 |
-54:12:08.3 |
HIP 89125 |
3.15 |
| 2026-04-14 00:00 |
18:11:14.30 |
-54:12:25.8 |
HIP 89125 |
2.95 |
| 2026-04-14 12:00 |
18:11:12.88 |
-54:12:43.2 |
HIP 89125 |
2.79 |
| 2026-04-15 00:00 |
18:11:11.41 |
-54:13:00.6 |
HIP 89125 |
2.67 |
| 2026-04-15 12:00 |
18:11:09.92 |
-54:13:17.8 |
HIP 89125 |
2.60 |
| 2026-04-16 00:00 |
18:11:08.38 |
-54:13:35.1 |
HIP 89125 |
2.58 |