| 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 |
-0.998 |
| 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) |
| 2026-09-20 00:00 |
11:03:59.20 |
-32:47:22.6 |
HIP 54092 |
12.16 |
| 2026-09-20 12:00 |
11:04:12.92 |
-32:49:14.5 |
HIP 54092 |
13.99 |
| 2026-09-21 00:00 |
11:04:26.61 |
-32:51:07.1 |
HIP 54092 |
16.36 |
| 2026-09-21 12:00 |
11:04:40.29 |
-32:53:00.4 |
HIP 54092 |
19.06 |
| 2026-09-22 00:00 |
11:04:53.93 |
-32:54:54.2 |
HIP 54092 |
21.98 |
| 2026-09-22 12:00 |
11:05:07.55 |
-32:56:48.7 |
HIP 54092 |
25.04 |
| 2026-09-23 00:00 |
11:05:21.14 |
-32:58:43.8 |
HIP 54092 |
28.19 |
| 2026-09-23 12:00 |
11:05:34.71 |
-33:00:39.5 |
HIP 54092 |
31.40 |
| 2026-09-24 00:00 |
11:05:48.25 |
-33:02:35.8 |
HIP 54349 |
32.15 |
| 2026-09-24 12:00 |
11:06:01.76 |
-33:04:32.7 |
HIP 54354 |
32.35 |
| 2026-09-25 00:00 |
11:06:15.24 |
-33:06:30.2 |
HIP 54354 |
29.36 |
| 2026-09-25 12:00 |
11:06:28.69 |
-33:08:28.3 |
HIP 54354 |
26.47 |
| 2026-09-26 00:00 |
11:06:42.11 |
-33:10:27.0 |
HIP 54354 |
23.73 |
| 2026-09-26 12:00 |
11:06:55.50 |
-33:12:26.3 |
HIP 54354 |
21.17 |
| 2026-09-27 00:00 |
11:07:08.86 |
-33:14:26.1 |
HIP 54354 |
18.88 |
| 2026-09-27 12:00 |
11:07:22.19 |
-33:16:26.6 |
HIP 54354 |
16.97 |
| 2026-09-28 00:00 |
11:07:35.49 |
-33:18:27.6 |
HIP 54354 |
15.58 |
| 2026-09-28 12:00 |
11:07:48.75 |
-33:20:29.2 |
HIP 54354 |
14.85 |
| 2026-09-29 00:00 |
11:08:01.98 |
-33:22:31.4 |
HIP 54354 |
14.89 |
| 2026-09-29 12:00 |
11:08:15.18 |
-33:24:34.1 |
HIP 54354 |
15.68 |
| 2026-09-30 00:00 |
11:08:28.34 |
-33:26:37.4 |
HIP 54354 |
17.12 |
| 2026-09-30 12:00 |
11:08:41.47 |
-33:28:41.3 |
HIP 54453 |
17.13 |
| 2026-10-01 00:00 |
11:08:54.56 |
-33:30:45.7 |
HIP 54453 |
15.85 |
| 2026-10-01 12:00 |
11:09:07.61 |
-33:32:50.7 |
HIP 54453 |
15.25 |
| 2026-10-02 00:00 |
11:09:20.63 |
-33:34:56.2 |
HIP 54453 |
15.38 |
| 2026-10-02 12:00 |
11:09:33.62 |
-33:37:02.3 |
HIP 54453 |
16.24 |
| 2026-10-03 00:00 |
11:09:46.56 |
-33:39:08.9 |
HIP 54453 |
17.71 |
| 2026-10-03 12:00 |
11:09:59.47 |
-33:41:16.1 |
HIP 54453 |
19.67 |
| 2026-10-04 00:00 |
11:10:12.33 |
-33:43:23.8 |
HIP 54453 |
21.97 |
| 2026-10-04 12:00 |
11:10:25.16 |
-33:45:32.0 |
HIP 54453 |
24.53 |
| 2026-10-05 00:00 |
11:10:37.95 |
-33:47:40.7 |
HIP 54453 |
27.26 |
| 2026-10-05 12:00 |
11:10:50.70 |
-33:49:50.0 |
HIP 54453 |
30.13 |
| 2026-10-06 00:00 |
11:11:03.40 |
-33:51:59.8 |
HIP 54823 |
29.49 |
| 2026-10-06 12:00 |
11:11:16.06 |
-33:54:10.2 |
HIP 54823 |
26.58 |
| 2026-10-07 00:00 |
11:11:28.68 |
-33:56:21.0 |
HIP 54823 |
23.82 |
| 2026-10-07 12:00 |
11:11:41.26 |
-33:58:32.3 |
HIP 54823 |
21.25 |
| 2026-10-08 00:00 |
11:11:53.79 |
-34:00:44.2 |
HIP 54823 |
18.97 |
| 2026-10-08 12:00 |
11:12:06.28 |
-34:02:56.5 |
HIP 54823 |
17.07 |
| 2026-10-09 00:00 |
11:12:18.72 |
-34:05:09.4 |
HIP 54823 |
15.71 |
| 2026-10-09 12:00 |
11:12:31.11 |
-34:07:22.7 |
HIP 54823 |
15.02 |
| 2026-10-10 00:00 |
11:12:43.46 |
-34:09:36.5 |
HIP 54779 |
14.94 |
| 2026-10-10 12:00 |
11:12:55.76 |
-34:11:50.8 |
HIP 54779 |
12.56 |
| 2026-10-11 00:00 |
11:13:08.01 |
-34:14:05.5 |
HIP 54779 |
10.71 |