| Parameter |
Value |
| Designation |
C/2023 K1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-09-07T17:57:17.956800Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:46Z |
| Obs used |
218 |
| NEO |
- |
| M1 |
6.200 |
| K1 |
27.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-05-27T02:15:06.998400Z |
| Discovery magnitude (MPC) |
18.64 c |
| Discovery observatory (MPC) |
M22 · ATLAS South Africa, Sutherland |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-07-23.0000000 |
| e |
0.99718017 |
| q (au) |
2.039540 |
| a (au) |
723.284257 |
| i (deg) |
137.998404 |
| Ω (om, deg) |
223.706343 |
| ω (w, deg) |
337.472407 |
| M (ma, deg) |
359.997631 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.725 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.725 |
| 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 |
| 2023-05-27 |
2023-09-02 |
+17.2597 |
-6.056 |
| 2023-09-09 |
2024-03-19 |
+19.3353 |
-8.589 |
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 |
08:29:28.10 |
+63:23:04.4 |
HIP 41512 |
18.85 |
| 2026-03-26 12:00 |
08:29:07.18 |
+63:21:17.1 |
HIP 41512 |
16.10 |
| 2026-03-27 00:00 |
08:28:46.58 |
+63:19:29.1 |
HIP 41512 |
13.45 |
| 2026-03-27 12:00 |
08:28:26.30 |
+63:17:40.2 |
HIP 41512 |
10.93 |
| 2026-03-28 00:00 |
08:28:06.33 |
+63:15:50.6 |
HIP 41512 |
8.66 |
| 2026-03-28 12:00 |
08:27:46.67 |
+63:14:00.2 |
HIP 41512 |
6.86 |
| 2026-03-29 00:00 |
08:27:27.32 |
+63:12:09.1 |
HIP 41512 |
5.95 |
| 2026-03-29 12:00 |
08:27:08.28 |
+63:10:17.3 |
HIP 41512 |
6.30 |
| 2026-03-30 00:00 |
08:26:49.55 |
+63:08:24.7 |
HIP 41512 |
7.73 |
| 2026-03-30 12:00 |
08:26:31.14 |
+63:06:31.5 |
HIP 41512 |
9.75 |
| 2026-03-31 00:00 |
08:26:13.03 |
+63:04:37.6 |
HIP 41512 |
12.06 |
| 2026-03-31 12:00 |
08:25:55.23 |
+63:02:43.1 |
HIP 41512 |
14.52 |
| 2026-04-01 00:00 |
08:25:37.74 |
+63:00:47.9 |
HIP 41512 |
17.05 |
| 2026-04-01 12:00 |
08:25:20.55 |
+62:58:52.1 |
HIP 41512 |
19.62 |
| 2026-04-02 00:00 |
08:25:03.67 |
+62:56:55.7 |
HIP 41512 |
22.21 |
| 2026-04-02 12:00 |
08:24:47.09 |
+62:54:58.8 |
HIP 41512 |
24.80 |
| 2026-04-03 00:00 |
08:24:30.82 |
+62:53:01.2 |
HIP 41512 |
27.40 |
| 2026-04-03 12:00 |
08:24:14.85 |
+62:51:03.2 |
HIP 41512 |
29.99 |
| 2026-04-04 00:00 |
08:23:59.18 |
+62:49:04.6 |
HIP 41180 |
31.09 |
| 2026-04-04 12:00 |
08:23:43.81 |
+62:47:05.5 |
HIP 41180 |
29.26 |
| 2026-04-05 00:00 |
08:23:28.74 |
+62:45:05.8 |
HIP 41180 |
27.54 |
| 2026-04-05 12:00 |
08:23:13.97 |
+62:43:05.8 |
HIP 41180 |
25.96 |
| 2026-04-06 00:00 |
08:22:59.50 |
+62:41:05.2 |
HIP 41180 |
24.55 |
| 2026-04-06 12:00 |
08:22:45.32 |
+62:39:04.2 |
HIP 41180 |
23.32 |
| 2026-04-07 00:00 |
08:22:31.44 |
+62:37:02.7 |
HIP 41180 |
22.31 |
| 2026-04-07 12:00 |
08:22:17.86 |
+62:35:00.9 |
HIP 40772 |
21.32 |
| 2026-04-08 00:00 |
08:22:04.56 |
+62:32:58.6 |
HIP 40772 |
19.47 |
| 2026-04-08 12:00 |
08:21:51.56 |
+62:30:55.9 |
HIP 40772 |
17.82 |
| 2026-04-09 00:00 |
08:21:38.85 |
+62:28:52.9 |
HIP 40772 |
16.43 |
| 2026-04-09 12:00 |
08:21:26.43 |
+62:26:49.5 |
HIP 40772 |
15.36 |
| 2026-04-10 00:00 |
08:21:14.30 |
+62:24:45.7 |
HIP 40772 |
14.68 |
| 2026-04-10 12:00 |
08:21:02.46 |
+62:22:41.7 |
HIP 40772 |
14.42 |
| 2026-04-11 00:00 |
08:20:50.90 |
+62:20:37.3 |
HIP 40772 |
14.62 |
| 2026-04-11 12:00 |
08:20:39.62 |
+62:18:32.6 |
HIP 40772 |
15.24 |
| 2026-04-12 00:00 |
08:20:28.63 |
+62:16:27.6 |
HIP 40772 |
16.24 |
| 2026-04-12 12:00 |
08:20:17.92 |
+62:14:22.3 |
HIP 40772 |
17.53 |
| 2026-04-13 00:00 |
08:20:07.49 |
+62:12:16.8 |
HIP 40772 |
19.06 |
| 2026-04-13 12:00 |
08:19:57.34 |
+62:10:11.0 |
HIP 40772 |
20.77 |
| 2026-04-14 00:00 |
08:19:47.47 |
+62:08:05.0 |
HIP 40772 |
22.62 |
| 2026-04-14 12:00 |
08:19:37.88 |
+62:05:58.8 |
HIP 40772 |
24.57 |
| 2026-04-15 00:00 |
08:19:28.56 |
+62:03:52.3 |
HIP 40899 |
24.72 |
| 2026-04-15 12:00 |
08:19:19.51 |
+62:01:45.7 |
HIP 40899 |
23.23 |
| 2026-04-16 00:00 |
08:19:10.74 |
+61:59:38.9 |
HIP 40899 |
21.87 |