| Parameter |
Value |
| Designation |
P/2019 A2 (ATLAS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-11-21T10:46:12.993600Z |
| Orbit solution date (soln_date, UTC) |
2021-08-06T00:42:48Z |
| Obs used |
284 |
| NEO |
- |
| M1 |
11.700 |
| K1 |
8.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-01-04T11:38:04.992000Z |
| Discovery magnitude (MPC) |
18.70 c |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-02-09.0000000 |
| e |
0.38199370 |
| q (au) |
3.542902 |
| a (au) |
5.732793 |
| i (deg) |
14.855261 |
| Ω (om, deg) |
139.462645 |
| ω (w, deg) |
324.226252 |
| M (ma, deg) |
5.712176 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.764 + 3.368\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.764 |
| n |
3.368 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
4.853 |
| 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) |
| 2026-05-12 00:00 |
19:59:15.98 |
-13:10:31.9 |
HIP 98352 |
8.79 |
| 2026-05-12 12:00 |
19:59:14.47 |
-13:10:24.4 |
HIP 98352 |
8.71 |
| 2026-05-13 00:00 |
19:59:12.83 |
-13:10:17.4 |
HIP 98352 |
8.62 |
| 2026-05-13 12:00 |
19:59:11.07 |
-13:10:10.9 |
HIP 98352 |
8.53 |
| 2026-05-14 00:00 |
19:59:09.18 |
-13:10:04.8 |
HIP 98352 |
8.44 |
| 2026-05-14 12:00 |
19:59:07.16 |
-13:09:59.2 |
HIP 98352 |
8.37 |
| 2026-05-15 00:00 |
19:59:05.02 |
-13:09:54.0 |
HIP 98352 |
8.31 |
| 2026-05-15 12:00 |
19:59:02.74 |
-13:09:49.3 |
HIP 98352 |
8.26 |
| 2026-05-16 00:00 |
19:59:00.34 |
-13:09:45.1 |
HIP 98352 |
8.25 |
| 2026-05-16 12:00 |
19:58:57.82 |
-13:09:41.3 |
HIP 98352 |
8.27 |
| 2026-05-17 00:00 |
19:58:55.16 |
-13:09:38.0 |
HIP 98352 |
8.32 |
| 2026-05-17 12:00 |
19:58:52.39 |
-13:09:35.2 |
HIP 98352 |
8.43 |
| 2026-05-18 00:00 |
19:58:49.48 |
-13:09:32.8 |
HIP 98352 |
8.58 |
| 2026-05-18 12:00 |
19:58:46.45 |
-13:09:30.9 |
HIP 98352 |
8.79 |
| 2026-05-19 00:00 |
19:58:43.29 |
-13:09:29.5 |
HIP 98352 |
9.06 |
| 2026-05-19 12:00 |
19:58:40.01 |
-13:09:28.5 |
HIP 98352 |
9.39 |
| 2026-05-20 00:00 |
19:58:36.60 |
-13:09:28.1 |
HIP 98352 |
9.78 |
| 2026-05-20 12:00 |
19:58:33.07 |
-13:09:28.1 |
HIP 98352 |
10.24 |
| 2026-05-21 00:00 |
19:58:29.42 |
-13:09:28.6 |
HIP 98352 |
10.75 |
| 2026-05-21 12:00 |
19:58:25.64 |
-13:09:29.6 |
HIP 98352 |
11.33 |
| 2026-05-22 00:00 |
19:58:21.74 |
-13:09:31.0 |
HIP 98352 |
11.96 |
| 2026-05-22 12:00 |
19:58:17.72 |
-13:09:32.9 |
HIP 98352 |
12.66 |
| 2026-05-23 00:00 |
19:58:13.57 |
-13:09:35.3 |
HIP 98352 |
13.40 |
| 2026-05-23 12:00 |
19:58:09.30 |
-13:09:38.2 |
HIP 98352 |
14.20 |
| 2026-05-24 00:00 |
19:58:04.91 |
-13:09:41.6 |
HIP 98352 |
15.05 |
| 2026-05-24 12:00 |
19:58:00.40 |
-13:09:45.5 |
HIP 98352 |
15.94 |
| 2026-05-25 00:00 |
19:57:55.77 |
-13:09:49.8 |
HIP 98352 |
16.89 |
| 2026-05-25 12:00 |
19:57:51.02 |
-13:09:54.6 |
HIP 98352 |
17.87 |
| 2026-05-26 00:00 |
19:57:46.15 |
-13:10:00.0 |
HIP 98352 |
18.90 |
| 2026-05-26 12:00 |
19:57:41.17 |
-13:10:05.7 |
HIP 98352 |
19.97 |
| 2026-05-27 00:00 |
19:57:36.06 |
-13:10:12.0 |
HIP 98352 |
21.08 |
| 2026-05-27 12:00 |
19:57:30.83 |
-13:10:18.7 |
HIP 98109 |
20.86 |
| 2026-05-28 00:00 |
19:57:25.49 |
-13:10:26.0 |
HIP 98109 |
19.69 |
| 2026-05-28 12:00 |
19:57:20.03 |
-13:10:33.7 |
HIP 98107 |
18.50 |
| 2026-05-29 00:00 |
19:57:14.45 |
-13:10:41.9 |
HIP 98107 |
17.30 |
| 2026-05-29 12:00 |
19:57:08.76 |
-13:10:50.6 |
HIP 98107 |
16.11 |
| 2026-05-30 00:00 |
19:57:02.95 |
-13:10:59.7 |
HIP 98107 |
14.91 |
| 2026-05-30 12:00 |
19:56:57.03 |
-13:11:09.4 |
HIP 98107 |
13.74 |
| 2026-05-31 00:00 |
19:56:50.99 |
-13:11:19.5 |
HIP 98107 |
12.60 |
| 2026-05-31 12:00 |
19:56:44.84 |
-13:11:30.1 |
HIP 98107 |
11.51 |
| 2026-06-01 00:00 |
19:56:38.58 |
-13:11:41.2 |
HIP 98107 |
10.51 |
| 2026-06-01 12:00 |
19:56:32.20 |
-13:11:52.8 |
HIP 98107 |
9.63 |
| 2026-06-02 00:00 |
19:56:25.71 |
-13:12:04.9 |
HIP 98107 |
8.92 |