| Parameter |
Value |
| Designation |
C/2023 E1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-07-01T02:34:44.604480Z |
| Orbit solution date (soln_date, UTC) |
2024-02-17T03:13:27Z |
| Obs used |
3004 |
| NEO |
Yes |
| M1 |
16.200 |
| K1 |
7.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-03-01T00:05:50.179200Z |
| Discovery magnitude (MPC) |
18.82 o |
| Discovery observatory (MPC) |
M22 · ATLAS South Africa, Sutherland |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-07-02.0000000 |
| e |
0.94690275 |
| q (au) |
1.026605 |
| a (au) |
19.334429 |
| i (deg) |
38.312983 |
| Ω (om, deg) |
164.574212 |
| ω (w, deg) |
105.894615 |
| M (ma, deg) |
0.010347 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.216 + 5.450\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.216 |
| n |
5.450 |
| gf |
0.997 |
| gb |
-0.697 |
| k |
0.942 |
| 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 |
| 2022-12-25 |
2023-06-30 |
+7.6115 |
-1.812 |
| 2023-07-01 |
2023-12-11 |
-0.5124 |
-1.544 |
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 |
03:36:34.89 |
-15:29:02.7 |
HIP 16921 |
17.00 |
| 2026-03-26 12:00 |
03:36:44.45 |
-15:27:23.0 |
HIP 16921 |
14.79 |
| 2026-03-27 00:00 |
03:36:54.06 |
-15:25:43.8 |
HIP 16921 |
12.83 |
| 2026-03-27 12:00 |
03:37:03.74 |
-15:24:05.1 |
HIP 16921 |
11.23 |
| 2026-03-28 00:00 |
03:37:13.47 |
-15:22:26.8 |
HIP 16921 |
10.17 |
| 2026-03-28 12:00 |
03:37:23.27 |
-15:20:49.1 |
HIP 16921 |
9.85 |
| 2026-03-29 00:00 |
03:37:33.13 |
-15:19:11.7 |
HIP 16921 |
10.33 |
| 2026-03-29 12:00 |
03:37:43.04 |
-15:17:34.9 |
HIP 16921 |
11.52 |
| 2026-03-30 00:00 |
03:37:53.01 |
-15:15:58.6 |
HIP 16921 |
13.24 |
| 2026-03-30 12:00 |
03:38:03.04 |
-15:14:22.7 |
HIP 16921 |
15.31 |
| 2026-03-31 00:00 |
03:38:13.13 |
-15:12:47.3 |
HIP 16921 |
17.62 |
| 2026-03-31 12:00 |
03:38:23.27 |
-15:11:12.4 |
HIP 16921 |
20.08 |
| 2026-04-01 00:00 |
03:38:33.47 |
-15:09:38.0 |
HIP 16921 |
22.64 |
| 2026-04-01 12:00 |
03:38:43.73 |
-15:08:04.2 |
HIP 17136 |
21.87 |
| 2026-04-02 00:00 |
03:38:54.03 |
-15:06:30.8 |
HIP 17136 |
19.97 |
| 2026-04-02 12:00 |
03:39:04.40 |
-15:04:57.9 |
HIP 17136 |
18.33 |
| 2026-04-03 00:00 |
03:39:14.81 |
-15:03:25.6 |
HIP 17136 |
17.03 |
| 2026-04-03 12:00 |
03:39:25.28 |
-15:01:53.7 |
HIP 17136 |
16.15 |
| 2026-04-04 00:00 |
03:39:35.80 |
-15:00:22.4 |
HIP 17136 |
15.77 |
| 2026-04-04 12:00 |
03:39:46.37 |
-14:58:51.6 |
HIP 17136 |
15.92 |
| 2026-04-05 00:00 |
03:39:57.00 |
-14:57:21.3 |
HIP 17136 |
16.60 |
| 2026-04-05 12:00 |
03:40:07.67 |
-14:55:51.6 |
HIP 17182 |
15.56 |
| 2026-04-06 00:00 |
03:40:18.39 |
-14:54:22.4 |
HIP 17182 |
12.85 |
| 2026-04-06 12:00 |
03:40:29.17 |
-14:52:53.7 |
HIP 17182 |
10.30 |
| 2026-04-07 00:00 |
03:40:39.99 |
-14:51:25.6 |
HIP 17182 |
8.06 |
| 2026-04-07 12:00 |
03:40:50.86 |
-14:49:58.0 |
HIP 17182 |
6.48 |
| 2026-04-08 00:00 |
03:41:01.78 |
-14:48:30.9 |
HIP 17182 |
6.11 |
| 2026-04-08 12:00 |
03:41:12.74 |
-14:47:04.4 |
HIP 17182 |
7.15 |
| 2026-04-09 00:00 |
03:41:23.76 |
-14:45:38.5 |
HIP 17182 |
9.12 |
| 2026-04-09 12:00 |
03:41:34.81 |
-14:44:13.1 |
HIP 17182 |
11.57 |
| 2026-04-10 00:00 |
03:41:45.92 |
-14:42:48.3 |
HIP 17182 |
14.26 |
| 2026-04-10 12:00 |
03:41:57.06 |
-14:41:24.0 |
HIP 17182 |
17.07 |
| 2026-04-11 00:00 |
03:42:08.26 |
-14:40:00.3 |
HIP 17268 |
18.52 |
| 2026-04-11 12:00 |
03:42:19.49 |
-14:38:37.2 |
HIP 17268 |
17.90 |
| 2026-04-12 00:00 |
03:42:30.77 |
-14:37:14.7 |
HIP 17268 |
17.80 |
| 2026-04-12 12:00 |
03:42:42.09 |
-14:35:52.7 |
HIP 17268 |
18.23 |
| 2026-04-13 00:00 |
03:42:53.46 |
-14:34:31.3 |
HIP 17268 |
19.16 |
| 2026-04-13 12:00 |
03:43:04.86 |
-14:33:10.6 |
HIP 17268 |
20.53 |
| 2026-04-14 00:00 |
03:43:16.31 |
-14:31:50.4 |
HIP 17268 |
22.25 |
| 2026-04-14 12:00 |
03:43:27.79 |
-14:30:30.8 |
HIP 17268 |
24.25 |
| 2026-04-15 00:00 |
03:43:39.32 |
-14:29:11.8 |
HIP 17268 |
26.48 |
| 2026-04-15 12:00 |
03:43:50.88 |
-14:27:53.4 |
HIP 17268 |
28.88 |
| 2026-04-16 00:00 |
03:44:02.48 |
-14:26:35.6 |
HIP 17268 |
31.40 |