| 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) |
| 2026-09-20 00:00 |
04:27:53.42 |
-17:07:19.2 |
HIP 20806 |
5.21 |
| 2026-09-20 12:00 |
04:27:50.72 |
-17:09:07.7 |
HIP 20806 |
5.21 |
| 2026-09-21 00:00 |
04:27:47.92 |
-17:10:56.1 |
HIP 20806 |
5.85 |
| 2026-09-21 12:00 |
04:27:45.03 |
-17:12:44.4 |
HIP 20806 |
6.97 |
| 2026-09-22 00:00 |
04:27:42.03 |
-17:14:32.7 |
HIP 20806 |
8.38 |
| 2026-09-22 12:00 |
04:27:38.94 |
-17:16:20.8 |
HIP 20806 |
9.97 |
| 2026-09-23 00:00 |
04:27:35.74 |
-17:18:08.9 |
HIP 20806 |
11.67 |
| 2026-09-23 12:00 |
04:27:32.45 |
-17:19:56.8 |
HIP 20806 |
13.43 |
| 2026-09-24 00:00 |
04:27:29.06 |
-17:21:44.6 |
HIP 20880 |
14.31 |
| 2026-09-24 12:00 |
04:27:25.57 |
-17:23:32.2 |
HIP 20880 |
14.94 |
| 2026-09-25 00:00 |
04:27:21.98 |
-17:25:19.8 |
HIP 20880 |
15.83 |
| 2026-09-25 12:00 |
04:27:18.29 |
-17:27:07.1 |
HIP 20880 |
16.92 |
| 2026-09-26 00:00 |
04:27:14.51 |
-17:28:54.4 |
HIP 20880 |
18.19 |
| 2026-09-26 12:00 |
04:27:10.63 |
-17:30:41.4 |
HIP 20880 |
19.60 |
| 2026-09-27 00:00 |
04:27:06.65 |
-17:32:28.3 |
HIP 20880 |
21.13 |
| 2026-09-27 12:00 |
04:27:02.58 |
-17:34:14.9 |
HIP 20839 |
20.92 |
| 2026-09-28 00:00 |
04:26:58.41 |
-17:36:01.4 |
HIP 20839 |
20.26 |
| 2026-09-28 12:00 |
04:26:54.14 |
-17:37:47.7 |
HIP 20695 |
19.09 |
| 2026-09-29 00:00 |
04:26:49.78 |
-17:39:33.8 |
HIP 20695 |
17.08 |
| 2026-09-29 12:00 |
04:26:45.32 |
-17:41:19.6 |
HIP 20695 |
15.08 |
| 2026-09-30 00:00 |
04:26:40.76 |
-17:43:05.2 |
HIP 20695 |
13.07 |
| 2026-09-30 12:00 |
04:26:36.11 |
-17:44:50.6 |
HIP 20695 |
11.08 |
| 2026-10-01 00:00 |
04:26:31.36 |
-17:46:35.7 |
HIP 20695 |
9.11 |
| 2026-10-01 12:00 |
04:26:26.52 |
-17:48:20.6 |
HIP 20695 |
7.18 |
| 2026-10-02 00:00 |
04:26:21.59 |
-17:50:05.2 |
HIP 20695 |
5.36 |
| 2026-10-02 12:00 |
04:26:16.56 |
-17:51:49.5 |
HIP 20695 |
3.82 |
| 2026-10-03 00:00 |
04:26:11.43 |
-17:53:33.5 |
HIP 20695 |
3.03 |
| 2026-10-03 12:00 |
04:26:06.21 |
-17:55:17.2 |
HIP 20695 |
3.56 |
| 2026-10-04 00:00 |
04:26:00.90 |
-17:57:00.7 |
HIP 20695 |
5.02 |
| 2026-10-04 12:00 |
04:25:55.50 |
-17:58:43.7 |
HIP 20695 |
6.84 |
| 2026-10-05 00:00 |
04:25:50.00 |
-18:00:26.5 |
HIP 20695 |
8.82 |
| 2026-10-05 12:00 |
04:25:44.41 |
-18:02:08.9 |
HIP 20695 |
10.86 |
| 2026-10-06 00:00 |
04:25:38.73 |
-18:03:51.0 |
HIP 20695 |
12.94 |
| 2026-10-06 12:00 |
04:25:32.96 |
-18:05:32.7 |
HIP 20695 |
15.06 |
| 2026-10-07 00:00 |
04:25:27.10 |
-18:07:14.1 |
HIP 20695 |
17.19 |
| 2026-10-07 12:00 |
04:25:21.14 |
-18:08:55.0 |
HIP 20695 |
19.35 |
| 2026-10-08 00:00 |
04:25:15.10 |
-18:10:35.6 |
HIP 20695 |
21.51 |
| 2026-10-08 12:00 |
04:25:08.96 |
-18:12:15.7 |
HIP 20695 |
23.69 |
| 2026-10-09 00:00 |
04:25:02.74 |
-18:13:55.5 |
HIP 20695 |
25.88 |
| 2026-10-09 12:00 |
04:24:56.43 |
-18:15:34.8 |
HIP 20695 |
28.08 |
| 2026-10-10 00:00 |
04:24:50.03 |
-18:17:13.7 |
HIP 20695 |
30.29 |
| 2026-10-10 12:00 |
04:24:43.55 |
-18:18:52.1 |
HIP 20695 |
32.52 |
| 2026-10-11 00:00 |
04:24:36.97 |
-18:20:30.1 |
HIP 20695 |
34.75 |