| Parameter |
Value |
| Designation |
C/2023 B2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-03-10T11:54:03.790080Z |
| Orbit solution date (soln_date, UTC) |
2023-12-12T20:44:25Z |
| Obs used |
1107 |
| NEO |
- |
| M1 |
5.800 |
| K1 |
34.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2023-01-21T23:14:22.070400Z |
| Discovery magnitude (MPC) |
18.82 c |
| Discovery observatory (MPC) |
M22 · ATLAS South Africa, Sutherland |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-04-20.0000000 |
| e |
0.99712391 |
| q (au) |
1.743129 |
| a (au) |
606.075015 |
| i (deg) |
40.770763 |
| Ω (om, deg) |
218.120594 |
| ω (w, deg) |
317.399433 |
| M (ma, deg) |
0.002676 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.836 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.836 |
| 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 |
| 2022-11-16 |
2023-03-09 |
+18.9790 |
-4.051 |
| 2023-03-11 |
2023-05-22 |
+44.4170 |
-11.509 |
| 2023-05-22 |
2023-07-17 |
-28.8936 |
+9.864 |
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 |
20:21:17.42 |
+23:16:52.6 |
HIP 100374 |
2.09 |
| 2026-05-12 12:00 |
20:21:15.56 |
+23:18:36.9 |
HIP 100374 |
3.75 |
| 2026-05-13 00:00 |
20:21:13.59 |
+23:20:20.7 |
HIP 100374 |
5.50 |
| 2026-05-13 12:00 |
20:21:11.53 |
+23:22:04.0 |
HIP 100374 |
7.27 |
| 2026-05-14 00:00 |
20:21:09.37 |
+23:23:46.8 |
HIP 100374 |
9.04 |
| 2026-05-14 12:00 |
20:21:07.11 |
+23:25:29.1 |
HIP 100374 |
10.82 |
| 2026-05-15 00:00 |
20:21:04.75 |
+23:27:10.9 |
HIP 100374 |
12.60 |
| 2026-05-15 12:00 |
20:21:02.30 |
+23:28:52.1 |
HIP 100374 |
14.37 |
| 2026-05-16 00:00 |
20:20:59.75 |
+23:30:32.9 |
HIP 100259 |
15.00 |
| 2026-05-16 12:00 |
20:20:57.11 |
+23:32:13.1 |
HIP 100259 |
13.67 |
| 2026-05-17 00:00 |
20:20:54.36 |
+23:33:52.8 |
HIP 100259 |
12.42 |
| 2026-05-17 12:00 |
20:20:51.53 |
+23:35:31.9 |
HIP 100259 |
11.31 |
| 2026-05-18 00:00 |
20:20:48.59 |
+23:37:10.5 |
HIP 100259 |
10.35 |
| 2026-05-18 12:00 |
20:20:45.57 |
+23:38:48.4 |
HIP 100259 |
9.61 |
| 2026-05-19 00:00 |
20:20:42.44 |
+23:40:25.9 |
HIP 100259 |
9.14 |
| 2026-05-19 12:00 |
20:20:39.22 |
+23:42:02.7 |
HIP 100259 |
8.97 |
| 2026-05-20 00:00 |
20:20:35.91 |
+23:43:38.9 |
HIP 100259 |
9.13 |
| 2026-05-20 12:00 |
20:20:32.50 |
+23:45:14.6 |
HIP 100259 |
9.59 |
| 2026-05-21 00:00 |
20:20:29.00 |
+23:46:49.6 |
HIP 100259 |
10.32 |
| 2026-05-21 12:00 |
20:20:25.41 |
+23:48:24.0 |
HIP 100259 |
11.27 |
| 2026-05-22 00:00 |
20:20:21.72 |
+23:49:57.8 |
HIP 100259 |
12.39 |
| 2026-05-22 12:00 |
20:20:17.94 |
+23:51:31.0 |
HIP 100259 |
13.63 |
| 2026-05-23 00:00 |
20:20:14.07 |
+23:53:03.5 |
HIP 100259 |
14.96 |
| 2026-05-23 12:00 |
20:20:10.11 |
+23:54:35.4 |
HIP 100259 |
16.37 |
| 2026-05-24 00:00 |
20:20:06.05 |
+23:56:06.6 |
HIP 100259 |
17.83 |
| 2026-05-24 12:00 |
20:20:01.91 |
+23:57:37.2 |
HIP 100259 |
19.34 |
| 2026-05-25 00:00 |
20:19:57.67 |
+23:59:07.1 |
HIP 100259 |
20.88 |
| 2026-05-25 12:00 |
20:19:53.34 |
+24:00:36.3 |
HIP 100200 |
22.08 |
| 2026-05-26 00:00 |
20:19:48.93 |
+24:02:04.9 |
HIP 100200 |
20.39 |
| 2026-05-26 12:00 |
20:19:44.42 |
+24:03:32.8 |
HIP 100200 |
18.71 |
| 2026-05-27 00:00 |
20:19:39.83 |
+24:05:00.0 |
HIP 100200 |
17.07 |
| 2026-05-27 12:00 |
20:19:35.14 |
+24:06:26.5 |
HIP 100200 |
15.47 |
| 2026-05-28 00:00 |
20:19:30.37 |
+24:07:52.3 |
HIP 100200 |
13.93 |
| 2026-05-28 12:00 |
20:19:25.51 |
+24:09:17.3 |
HIP 100200 |
12.47 |
| 2026-05-29 00:00 |
20:19:20.57 |
+24:10:41.7 |
HIP 100200 |
11.12 |
| 2026-05-29 12:00 |
20:19:15.53 |
+24:12:05.3 |
HIP 100200 |
9.94 |
| 2026-05-30 00:00 |
20:19:10.41 |
+24:13:28.2 |
HIP 100200 |
8.98 |
| 2026-05-30 12:00 |
20:19:05.21 |
+24:14:50.4 |
HIP 100200 |
8.33 |
| 2026-05-31 00:00 |
20:18:59.92 |
+24:16:11.8 |
HIP 100200 |
8.06 |
| 2026-05-31 12:00 |
20:18:54.54 |
+24:17:32.5 |
HIP 100200 |
8.23 |
| 2026-06-01 00:00 |
20:18:49.08 |
+24:18:52.4 |
HIP 100200 |
8.79 |
| 2026-06-01 12:00 |
20:18:43.53 |
+24:20:11.6 |
HIP 100200 |
9.70 |
| 2026-06-02 00:00 |
20:18:37.91 |
+24:21:30.0 |
HIP 100080 |
10.19 |