| Parameter |
Value |
| Designation |
C/2023 T2 (Borisov) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-12-22T18:54:38.292480Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:50Z |
| Obs used |
368 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
18.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2023-10-14T16:40:30.720000Z |
| Discovery magnitude (MPC) |
19.40 G |
| Discovery observatory (MPC) |
L51 · MARGO, Nauchnyi |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-11-23.0000000 |
| e |
0.99137332 |
| q (au) |
1.995438 |
| a (au) |
231.310079 |
| i (deg) |
48.596685 |
| Ω (om, deg) |
317.534632 |
| ω (w, deg) |
111.190785 |
| M (ma, deg) |
359.991654 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.017 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.017 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 2023-08-14 |
2023-12-19 |
+8.4189 |
-2.661 |
| 2023-12-31 |
2024-04-05 |
-9.5022 |
+2.693 |
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 |
10:20:43.59 |
-32:44:53.1 |
HIP 50565 |
12.34 |
| 2026-05-12 12:00 |
10:20:42.43 |
-32:43:03.3 |
HIP 50565 |
12.11 |
| 2026-05-13 00:00 |
10:20:41.40 |
-32:41:13.9 |
HIP 50565 |
12.18 |
| 2026-05-13 12:00 |
10:20:40.52 |
-32:39:25.0 |
HIP 50565 |
12.55 |
| 2026-05-14 00:00 |
10:20:39.77 |
-32:37:36.6 |
HIP 50565 |
13.18 |
| 2026-05-14 12:00 |
10:20:39.16 |
-32:35:48.7 |
HIP 50565 |
14.04 |
| 2026-05-15 00:00 |
10:20:38.69 |
-32:34:01.3 |
HIP 50565 |
15.08 |
| 2026-05-15 12:00 |
10:20:38.35 |
-32:32:14.4 |
HIP 50544 |
15.15 |
| 2026-05-16 00:00 |
10:20:38.15 |
-32:30:28.1 |
HIP 50544 |
15.29 |
| 2026-05-16 12:00 |
10:20:38.09 |
-32:28:42.3 |
HIP 50544 |
15.66 |
| 2026-05-17 00:00 |
10:20:38.16 |
-32:26:57.0 |
HIP 50544 |
16.23 |
| 2026-05-17 12:00 |
10:20:38.37 |
-32:25:12.4 |
HIP 50544 |
16.99 |
| 2026-05-18 00:00 |
10:20:38.71 |
-32:23:28.3 |
HIP 50544 |
17.90 |
| 2026-05-18 12:00 |
10:20:39.19 |
-32:21:44.8 |
HIP 50544 |
18.95 |
| 2026-05-19 00:00 |
10:20:39.80 |
-32:20:01.9 |
HIP 50544 |
20.11 |
| 2026-05-19 12:00 |
10:20:40.54 |
-32:18:19.6 |
HIP 50544 |
21.36 |
| 2026-05-20 00:00 |
10:20:41.42 |
-32:16:37.9 |
HIP 50795 |
21.98 |
| 2026-05-20 12:00 |
10:20:42.43 |
-32:14:56.8 |
HIP 50795 |
22.48 |
| 2026-05-21 00:00 |
10:20:43.57 |
-32:13:16.4 |
HIP 50795 |
23.07 |
| 2026-05-21 12:00 |
10:20:44.84 |
-32:11:36.7 |
HIP 50641 |
22.90 |
| 2026-05-22 00:00 |
10:20:46.24 |
-32:09:57.6 |
HIP 50641 |
21.29 |
| 2026-05-22 12:00 |
10:20:47.77 |
-32:08:19.2 |
HIP 50641 |
19.70 |
| 2026-05-23 00:00 |
10:20:49.43 |
-32:06:41.4 |
HIP 50641 |
18.15 |
| 2026-05-23 12:00 |
10:20:51.21 |
-32:05:04.3 |
HIP 50641 |
16.64 |
| 2026-05-24 00:00 |
10:20:53.13 |
-32:03:27.9 |
HIP 50641 |
15.18 |
| 2026-05-24 12:00 |
10:20:55.17 |
-32:01:52.2 |
HIP 50641 |
13.78 |
| 2026-05-25 00:00 |
10:20:57.34 |
-32:00:17.2 |
HIP 50641 |
12.47 |
| 2026-05-25 12:00 |
10:20:59.63 |
-31:58:43.0 |
HIP 50641 |
11.26 |
| 2026-05-26 00:00 |
10:21:02.05 |
-31:57:09.4 |
HIP 50641 |
10.21 |
| 2026-05-26 12:00 |
10:21:04.59 |
-31:55:36.6 |
HIP 50641 |
9.36 |
| 2026-05-27 00:00 |
10:21:07.26 |
-31:54:04.5 |
HIP 50641 |
8.76 |
| 2026-05-27 12:00 |
10:21:10.04 |
-31:52:33.1 |
HIP 50641 |
8.47 |
| 2026-05-28 00:00 |
10:21:12.96 |
-31:51:02.5 |
HIP 50641 |
8.52 |
| 2026-05-28 12:00 |
10:21:15.99 |
-31:49:32.6 |
HIP 50641 |
8.90 |
| 2026-05-29 00:00 |
10:21:19.14 |
-31:48:03.5 |
HIP 50641 |
9.58 |
| 2026-05-29 12:00 |
10:21:22.42 |
-31:46:35.1 |
HIP 50641 |
10.48 |
| 2026-05-30 00:00 |
10:21:25.81 |
-31:45:07.6 |
HIP 50641 |
11.57 |
| 2026-05-30 12:00 |
10:21:29.32 |
-31:43:40.8 |
HIP 50641 |
12.79 |
| 2026-05-31 00:00 |
10:21:32.95 |
-31:42:14.7 |
HIP 50641 |
14.11 |
| 2026-05-31 12:00 |
10:21:36.70 |
-31:40:49.5 |
HIP 50641 |
15.51 |
| 2026-06-01 00:00 |
10:21:40.57 |
-31:39:25.1 |
HIP 50641 |
16.96 |
| 2026-06-01 12:00 |
10:21:44.55 |
-31:38:01.4 |
HIP 50641 |
18.45 |
| 2026-06-02 00:00 |
10:21:48.65 |
-31:36:38.6 |
HIP 50641 |
19.98 |