| 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) |
| 2026-07-29 00:00 |
17:59:08.82 |
-54:24:50.5 |
HIP 88027 |
10.42 |
| 2026-07-29 12:00 |
17:59:05.66 |
-54:24:37.4 |
HIP 88027 |
10.50 |
| 2026-07-30 00:00 |
17:59:02.52 |
-54:24:24.1 |
HIP 88027 |
10.61 |
| 2026-07-30 12:00 |
17:58:59.41 |
-54:24:10.8 |
HIP 88027 |
10.75 |
| 2026-07-31 00:00 |
17:58:56.31 |
-54:23:57.3 |
HIP 88027 |
10.91 |
| 2026-07-31 12:00 |
17:58:53.25 |
-54:23:43.6 |
HIP 88027 |
11.09 |
| 2026-08-01 00:00 |
17:58:50.21 |
-54:23:29.9 |
HIP 88027 |
11.30 |
| 2026-08-01 12:00 |
17:58:47.19 |
-54:23:16.0 |
HIP 88027 |
11.52 |
| 2026-08-02 00:00 |
17:58:44.20 |
-54:23:02.0 |
HIP 88027 |
11.77 |
| 2026-08-02 12:00 |
17:58:41.23 |
-54:22:47.9 |
HIP 88027 |
12.03 |
| 2026-08-03 00:00 |
17:58:38.29 |
-54:22:33.7 |
HIP 88027 |
12.30 |
| 2026-08-03 12:00 |
17:58:35.38 |
-54:22:19.3 |
HIP 88027 |
12.59 |
| 2026-08-04 00:00 |
17:58:32.49 |
-54:22:04.8 |
HIP 88027 |
12.90 |
| 2026-08-04 12:00 |
17:58:29.62 |
-54:21:50.2 |
HIP 88027 |
13.21 |
| 2026-08-05 00:00 |
17:58:26.79 |
-54:21:35.5 |
HIP 88027 |
13.54 |
| 2026-08-05 12:00 |
17:58:23.98 |
-54:21:20.7 |
HIP 88027 |
13.88 |
| 2026-08-06 00:00 |
17:58:21.20 |
-54:21:05.8 |
HIP 88027 |
14.22 |
| 2026-08-06 12:00 |
17:58:18.44 |
-54:20:50.7 |
HIP 88027 |
14.57 |
| 2026-08-07 00:00 |
17:58:15.71 |
-54:20:35.6 |
HIP 88027 |
14.93 |
| 2026-08-07 12:00 |
17:58:13.01 |
-54:20:20.3 |
HIP 88027 |
15.30 |
| 2026-08-08 00:00 |
17:58:10.34 |
-54:20:04.9 |
HIP 88027 |
15.67 |
| 2026-08-08 12:00 |
17:58:07.69 |
-54:19:49.5 |
HIP 87821 |
15.35 |
| 2026-08-09 00:00 |
17:58:05.07 |
-54:19:33.9 |
HIP 87821 |
15.03 |
| 2026-08-09 12:00 |
17:58:02.48 |
-54:19:18.2 |
HIP 87821 |
14.72 |
| 2026-08-10 00:00 |
17:57:59.92 |
-54:19:02.4 |
HIP 87821 |
14.42 |
| 2026-08-10 12:00 |
17:57:57.39 |
-54:18:46.5 |
HIP 87821 |
14.14 |
| 2026-08-11 00:00 |
17:57:54.89 |
-54:18:30.5 |
HIP 87821 |
13.86 |
| 2026-08-11 12:00 |
17:57:52.41 |
-54:18:14.3 |
HIP 87821 |
13.61 |
| 2026-08-12 00:00 |
17:57:49.97 |
-54:17:58.1 |
HIP 87821 |
13.36 |
| 2026-08-12 12:00 |
17:57:47.55 |
-54:17:41.8 |
HIP 87821 |
13.14 |
| 2026-08-13 00:00 |
17:57:45.17 |
-54:17:25.4 |
HIP 87821 |
12.93 |
| 2026-08-13 12:00 |
17:57:42.81 |
-54:17:08.9 |
HIP 87821 |
12.73 |
| 2026-08-14 00:00 |
17:57:40.49 |
-54:16:52.4 |
HIP 87821 |
12.55 |
| 2026-08-14 12:00 |
17:57:38.20 |
-54:16:35.7 |
HIP 87821 |
12.39 |
| 2026-08-15 00:00 |
17:57:35.93 |
-54:16:18.9 |
HIP 87821 |
12.25 |
| 2026-08-15 12:00 |
17:57:33.70 |
-54:16:02.0 |
HIP 87821 |
12.12 |
| 2026-08-16 00:00 |
17:57:31.50 |
-54:15:45.1 |
HIP 87821 |
12.02 |
| 2026-08-16 12:00 |
17:57:29.33 |
-54:15:28.1 |
HIP 87821 |
11.93 |
| 2026-08-17 00:00 |
17:57:27.18 |
-54:15:10.9 |
HIP 87821 |
11.86 |
| 2026-08-17 12:00 |
17:57:25.08 |
-54:14:53.7 |
HIP 87821 |
11.81 |
| 2026-08-18 00:00 |
17:57:23.00 |
-54:14:36.5 |
HIP 87821 |
11.78 |
| 2026-08-18 12:00 |
17:57:20.95 |
-54:14:19.1 |
HIP 87821 |
11.77 |
| 2026-08-19 00:00 |
17:57:18.94 |
-54:14:01.6 |
HIP 87821 |
11.78 |