| Parameter |
Value |
| Designation |
427P/ATLAS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-07-28T00:34:23.257920Z |
| Orbit solution date (soln_date, UTC) |
2021-10-08T07:06:18Z |
| Obs used |
434 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
19.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-06-09T01:43:41.059200Z |
| Discovery magnitude (MPC) |
24.00 G |
| Discovery observatory (MPC) |
I11 · Gemini South Observatory, Cerro Pachon |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-11-23.0000000 |
| e |
0.31304498 |
| q (au) |
2.178224 |
| a (au) |
3.170840 |
| i (deg) |
11.849372 |
| Ω (om, deg) |
252.391001 |
| ω (w, deg) |
99.944337 |
| M (ma, deg) |
20.593814 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 3.940\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
3.940 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.840 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
11:28:18.65 |
-12:46:53.6 |
HIP 55910 |
22.03 |
| 2026-03-26 12:00 |
11:27:58.84 |
-12:44:14.4 |
HIP 55900 |
19.39 |
| 2026-03-27 00:00 |
11:27:39.12 |
-12:41:34.3 |
HIP 55900 |
15.57 |
| 2026-03-27 12:00 |
11:27:19.50 |
-12:38:53.3 |
HIP 55900 |
13.01 |
| 2026-03-28 00:00 |
11:26:59.97 |
-12:36:11.6 |
HIP 55900 |
12.47 |
| 2026-03-28 12:00 |
11:26:40.55 |
-12:33:29.2 |
HIP 55874 |
14.00 |
| 2026-03-29 00:00 |
11:26:21.23 |
-12:30:45.9 |
HIP 55874 |
15.06 |
| 2026-03-29 12:00 |
11:26:02.01 |
-12:28:02.0 |
HIP 55874 |
17.78 |
| 2026-03-30 00:00 |
11:25:42.91 |
-12:25:17.4 |
HIP 55752 |
15.80 |
| 2026-03-30 12:00 |
11:25:23.92 |
-12:22:32.2 |
HIP 55752 |
12.52 |
| 2026-03-31 00:00 |
11:25:05.05 |
-12:19:46.4 |
HIP 55752 |
11.02 |
| 2026-03-31 12:00 |
11:24:46.30 |
-12:17:00.0 |
HIP 55752 |
11.96 |
| 2026-04-01 00:00 |
11:24:27.67 |
-12:14:13.0 |
HIP 55752 |
14.88 |
| 2026-04-01 12:00 |
11:24:09.17 |
-12:11:25.6 |
HIP 55600 |
12.51 |
| 2026-04-02 00:00 |
11:23:50.81 |
-12:08:37.6 |
HIP 55600 |
7.27 |
| 2026-04-02 12:00 |
11:23:32.57 |
-12:05:49.2 |
HIP 55600 |
2.32 |
| 2026-04-03 00:00 |
11:23:14.47 |
-12:03:00.3 |
HIP 55600 |
3.64 |
| 2026-04-03 12:00 |
11:22:56.52 |
-12:00:11.1 |
HIP 55600 |
8.70 |
| 2026-04-04 00:00 |
11:22:38.70 |
-11:57:21.5 |
HIP 55600 |
13.86 |
| 2026-04-04 12:00 |
11:22:21.04 |
-11:54:31.6 |
HIP 55600 |
19.01 |
| 2026-04-05 00:00 |
11:22:03.52 |
-11:51:41.4 |
HIP 55600 |
24.14 |
| 2026-04-05 12:00 |
11:21:46.15 |
-11:48:50.9 |
HIP 55600 |
29.25 |
| 2026-04-06 00:00 |
11:21:28.94 |
-11:46:00.1 |
HIP 55314 |
26.46 |
| 2026-04-06 12:00 |
11:21:11.88 |
-11:43:09.2 |
HIP 55314 |
22.45 |
| 2026-04-07 00:00 |
11:20:54.99 |
-11:40:18.0 |
HIP 55314 |
18.99 |
| 2026-04-07 12:00 |
11:20:38.26 |
-11:37:26.8 |
HIP 55314 |
16.40 |
| 2026-04-08 00:00 |
11:20:21.69 |
-11:34:35.4 |
HIP 55314 |
15.09 |
| 2026-04-08 12:00 |
11:20:05.30 |
-11:31:43.9 |
HIP 55314 |
15.37 |
| 2026-04-09 00:00 |
11:19:49.08 |
-11:28:52.4 |
HIP 55314 |
17.13 |
| 2026-04-09 12:00 |
11:19:33.03 |
-11:26:00.8 |
HIP 55314 |
19.97 |
| 2026-04-10 00:00 |
11:19:17.15 |
-11:23:09.3 |
HIP 55345 |
20.68 |
| 2026-04-10 12:00 |
11:19:01.46 |
-11:20:17.7 |
HIP 55345 |
20.90 |
| 2026-04-11 00:00 |
11:18:45.95 |
-11:17:26.3 |
HIP 55345 |
22.14 |
| 2026-04-11 12:00 |
11:18:30.63 |
-11:14:35.0 |
HIP 55345 |
24.22 |
| 2026-04-12 00:00 |
11:18:15.49 |
-11:11:43.7 |
HIP 55145 |
23.25 |
| 2026-04-12 12:00 |
11:18:00.54 |
-11:08:52.7 |
HIP 55145 |
18.93 |
| 2026-04-13 00:00 |
11:17:45.78 |
-11:06:01.8 |
HIP 55145 |
14.84 |
| 2026-04-13 12:00 |
11:17:31.22 |
-11:03:11.2 |
HIP 55145 |
11.17 |
| 2026-04-14 00:00 |
11:17:16.85 |
-11:00:20.8 |
HIP 55145 |
8.41 |
| 2026-04-14 12:00 |
11:17:02.68 |
-10:57:30.6 |
HIP 55145 |
7.57 |
| 2026-04-15 00:00 |
11:16:48.72 |
-10:54:40.8 |
HIP 55145 |
9.13 |
| 2026-04-15 12:00 |
11:16:34.95 |
-10:51:51.4 |
HIP 55145 |
12.16 |
| 2026-04-16 00:00 |
11:16:21.39 |
-10:49:02.3 |
HIP 55027 |
13.62 |