| 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 |
-0.553 |
| 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) |
| 2026-09-20 00:00 |
09:10:50.49 |
+57:00:21.5 |
HIP 45213 |
16.77 |
| 2026-09-20 12:00 |
09:11:00.45 |
+57:01:20.2 |
HIP 45213 |
15.73 |
| 2026-09-21 00:00 |
09:11:10.31 |
+57:02:19.8 |
HIP 45213 |
14.81 |
| 2026-09-21 12:00 |
09:11:20.07 |
+57:03:20.4 |
HIP 45213 |
14.06 |
| 2026-09-22 00:00 |
09:11:29.72 |
+57:04:21.8 |
HIP 45213 |
13.49 |
| 2026-09-22 12:00 |
09:11:39.28 |
+57:05:24.1 |
HIP 45213 |
13.13 |
| 2026-09-23 00:00 |
09:11:48.73 |
+57:06:27.2 |
HIP 45213 |
13.00 |
| 2026-09-23 12:00 |
09:11:58.08 |
+57:07:31.3 |
HIP 45213 |
13.10 |
| 2026-09-24 00:00 |
09:12:07.32 |
+57:08:36.2 |
HIP 45213 |
13.43 |
| 2026-09-24 12:00 |
09:12:16.46 |
+57:09:42.1 |
HIP 45213 |
13.97 |
| 2026-09-25 00:00 |
09:12:25.48 |
+57:10:48.8 |
HIP 45213 |
14.69 |
| 2026-09-25 12:00 |
09:12:34.40 |
+57:11:56.3 |
HIP 45213 |
15.58 |
| 2026-09-26 00:00 |
09:12:43.22 |
+57:13:04.8 |
HIP 45213 |
16.60 |
| 2026-09-26 12:00 |
09:12:51.92 |
+57:14:14.2 |
HIP 45213 |
17.72 |
| 2026-09-27 00:00 |
09:13:00.51 |
+57:15:24.4 |
HIP 45213 |
18.94 |
| 2026-09-27 12:00 |
09:13:08.99 |
+57:16:35.5 |
HIP 45213 |
20.24 |
| 2026-09-28 00:00 |
09:13:17.36 |
+57:17:47.4 |
HIP 45213 |
21.59 |
| 2026-09-28 12:00 |
09:13:25.61 |
+57:19:00.3 |
HIP 45213 |
23.00 |
| 2026-09-29 00:00 |
09:13:33.74 |
+57:20:14.0 |
HIP 45213 |
24.44 |
| 2026-09-29 12:00 |
09:13:41.77 |
+57:21:28.6 |
HIP 45213 |
25.92 |
| 2026-09-30 00:00 |
09:13:49.67 |
+57:22:44.0 |
HIP 45213 |
27.43 |
| 2026-09-30 12:00 |
09:13:57.46 |
+57:24:00.3 |
HIP 45213 |
28.96 |
| 2026-10-01 00:00 |
09:14:05.13 |
+57:25:17.5 |
HIP 45610 |
30.32 |
| 2026-10-01 12:00 |
09:14:12.67 |
+57:26:35.6 |
HIP 45610 |
29.18 |
| 2026-10-02 00:00 |
09:14:20.10 |
+57:27:54.5 |
HIP 45610 |
28.10 |
| 2026-10-02 12:00 |
09:14:27.40 |
+57:29:14.3 |
HIP 45610 |
27.10 |
| 2026-10-03 00:00 |
09:14:34.58 |
+57:30:35.0 |
HIP 45610 |
26.18 |
| 2026-10-03 12:00 |
09:14:41.64 |
+57:31:56.5 |
HIP 45610 |
25.35 |
| 2026-10-04 00:00 |
09:14:48.57 |
+57:33:18.9 |
HIP 45610 |
24.64 |
| 2026-10-04 12:00 |
09:14:55.37 |
+57:34:42.1 |
HIP 45610 |
24.03 |
| 2026-10-05 00:00 |
09:15:02.04 |
+57:36:06.2 |
HIP 45610 |
23.55 |
| 2026-10-05 12:00 |
09:15:08.59 |
+57:37:31.2 |
HIP 45610 |
23.20 |
| 2026-10-06 00:00 |
09:15:15.00 |
+57:38:57.0 |
HIP 45610 |
22.99 |
| 2026-10-06 12:00 |
09:15:21.28 |
+57:40:23.6 |
HIP 45610 |
22.93 |
| 2026-10-07 00:00 |
09:15:27.43 |
+57:41:51.2 |
HIP 45610 |
23.01 |
| 2026-10-07 12:00 |
09:15:33.44 |
+57:43:19.5 |
HIP 45628 |
22.57 |
| 2026-10-08 00:00 |
09:15:39.32 |
+57:44:48.7 |
HIP 45628 |
21.17 |
| 2026-10-08 12:00 |
09:15:45.06 |
+57:46:18.8 |
HIP 45628 |
19.83 |
| 2026-10-09 00:00 |
09:15:50.67 |
+57:47:49.6 |
HIP 45628 |
18.57 |
| 2026-10-09 12:00 |
09:15:56.13 |
+57:49:21.4 |
HIP 45628 |
17.38 |
| 2026-10-10 00:00 |
09:16:01.45 |
+57:50:53.9 |
HIP 45628 |
16.31 |
| 2026-10-10 12:00 |
09:16:06.63 |
+57:52:27.3 |
HIP 45628 |
15.36 |
| 2026-10-11 00:00 |
09:16:11.67 |
+57:54:01.5 |
HIP 45628 |
14.58 |