| Parameter |
Value |
| Designation |
C/2021 Y1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-04-30T16:42:49.288320Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:29Z |
| Obs used |
1857 |
| NEO |
- |
| M1 |
12.000 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-12-26T06:50:24.691200Z |
| Discovery magnitude (MPC) |
18.99 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-10-17.0000000 |
| e |
1.00083371 |
| q (au) |
2.032510 |
| a (au) |
-2437.901109 |
| i (deg) |
77.187480 |
| Ω (om, deg) |
244.769593 |
| ω (w, deg) |
245.810207 |
| M (ma, deg) |
-0.001602 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.482 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.482 |
| n |
2.000 |
| gf |
0.833 |
| gb |
-0.807 |
| k |
0.997 |
| δ90 |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
16:51:52.02 |
-10:35:28.1 |
HIP 82642 |
26.87 |
| 2026-03-26 12:00 |
16:51:48.12 |
-10:34:07.6 |
HIP 82642 |
28.27 |
| 2026-03-27 00:00 |
16:51:44.11 |
-10:32:46.9 |
HIP 82642 |
29.72 |
| 2026-03-27 12:00 |
16:51:39.99 |
-10:31:26.2 |
HIP 82369 |
31.18 |
| 2026-03-28 00:00 |
16:51:35.77 |
-10:30:05.3 |
HIP 82369 |
30.99 |
| 2026-03-28 12:00 |
16:51:31.45 |
-10:28:44.3 |
HIP 82369 |
30.89 |
| 2026-03-29 00:00 |
16:51:27.02 |
-10:27:23.2 |
HIP 82369 |
30.86 |
| 2026-03-29 12:00 |
16:51:22.49 |
-10:26:01.9 |
HIP 82369 |
30.91 |
| 2026-03-30 00:00 |
16:51:17.86 |
-10:24:40.6 |
HIP 82369 |
31.04 |
| 2026-03-30 12:00 |
16:51:13.12 |
-10:23:19.2 |
HIP 82369 |
31.25 |
| 2026-03-31 00:00 |
16:51:08.29 |
-10:21:57.7 |
HIP 82369 |
31.56 |
| 2026-03-31 12:00 |
16:51:03.35 |
-10:20:36.0 |
HIP 82369 |
31.94 |
| 2026-04-01 00:00 |
16:50:58.31 |
-10:19:14.3 |
HIP 82369 |
32.42 |
| 2026-04-01 12:00 |
16:50:53.16 |
-10:17:52.5 |
HIP 82369 |
32.98 |
| 2026-04-02 00:00 |
16:50:47.92 |
-10:16:30.6 |
HIP 82369 |
33.62 |
| 2026-04-02 12:00 |
16:50:42.58 |
-10:15:08.7 |
HIP 82298 |
32.56 |
| 2026-04-03 00:00 |
16:50:37.14 |
-10:13:46.7 |
HIP 82298 |
30.67 |
| 2026-04-03 12:00 |
16:50:31.59 |
-10:12:24.5 |
HIP 82298 |
28.76 |
| 2026-04-04 00:00 |
16:50:25.95 |
-10:11:02.4 |
HIP 82298 |
26.83 |
| 2026-04-04 12:00 |
16:50:20.21 |
-10:09:40.1 |
HIP 82298 |
24.88 |
| 2026-04-05 00:00 |
16:50:14.37 |
-10:08:17.8 |
HIP 82298 |
22.92 |
| 2026-04-05 12:00 |
16:50:08.44 |
-10:06:55.5 |
HIP 82298 |
20.94 |
| 2026-04-06 00:00 |
16:50:02.41 |
-10:05:33.1 |
HIP 82298 |
18.95 |
| 2026-04-06 12:00 |
16:49:56.28 |
-10:04:10.6 |
HIP 82298 |
16.94 |
| 2026-04-07 00:00 |
16:49:50.05 |
-10:02:48.1 |
HIP 82298 |
14.92 |
| 2026-04-07 12:00 |
16:49:43.73 |
-10:01:25.5 |
HIP 82298 |
12.89 |
| 2026-04-08 00:00 |
16:49:37.31 |
-10:00:03.0 |
HIP 82298 |
10.86 |
| 2026-04-08 12:00 |
16:49:30.80 |
-09:58:40.3 |
HIP 82298 |
8.83 |
| 2026-04-09 00:00 |
16:49:24.19 |
-09:57:17.7 |
HIP 82298 |
6.84 |
| 2026-04-09 12:00 |
16:49:17.49 |
-09:55:55.0 |
HIP 82298 |
4.93 |
| 2026-04-10 00:00 |
16:49:10.70 |
-09:54:32.3 |
HIP 82298 |
3.32 |
| 2026-04-10 12:00 |
16:49:03.81 |
-09:53:09.6 |
HIP 82298 |
2.65 |
| 2026-04-11 00:00 |
16:48:56.83 |
-09:51:46.9 |
HIP 82298 |
3.55 |
| 2026-04-11 12:00 |
16:48:49.76 |
-09:50:24.2 |
HIP 82298 |
5.29 |
| 2026-04-12 00:00 |
16:48:42.60 |
-09:49:01.5 |
HIP 82298 |
7.31 |
| 2026-04-12 12:00 |
16:48:35.34 |
-09:47:38.7 |
HIP 82298 |
9.44 |
| 2026-04-13 00:00 |
16:48:28.00 |
-09:46:16.0 |
HIP 82298 |
11.63 |
| 2026-04-13 12:00 |
16:48:20.57 |
-09:44:53.3 |
HIP 82298 |
13.86 |
| 2026-04-14 00:00 |
16:48:13.05 |
-09:43:30.6 |
HIP 82298 |
16.13 |
| 2026-04-14 12:00 |
16:48:05.44 |
-09:42:08.0 |
HIP 82298 |
18.42 |
| 2026-04-15 00:00 |
16:47:57.74 |
-09:40:45.3 |
HIP 82298 |
20.73 |
| 2026-04-15 12:00 |
16:47:49.96 |
-09:39:22.7 |
HIP 82298 |
23.07 |
| 2026-04-16 00:00 |
16:47:42.09 |
-09:38:00.1 |
HIP 82298 |
25.42 |