| 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
$$
M_a = (10.766 + 3.368\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.766 |
| n |
3.368 |
| gf |
0.800 |
| gb |
-0.581 |
| k |
1.000 |
| δ90 |
4.812 |
| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
19:56:19.11 |
-13:12:17.5 |
HIP 98107 |
8.45 |
| 2026-06-03 00:00 |
19:56:12.40 |
-13:12:30.5 |
HIP 98107 |
8.26 |
| 2026-06-03 12:00 |
19:56:05.57 |
-13:12:44.1 |
HIP 98107 |
8.41 |
| 2026-06-04 00:00 |
19:55:58.64 |
-13:12:58.1 |
HIP 98107 |
8.88 |
| 2026-06-04 12:00 |
19:55:51.60 |
-13:13:12.6 |
HIP 98107 |
9.64 |
| 2026-06-05 00:00 |
19:55:44.45 |
-13:13:27.5 |
HIP 98107 |
10.64 |
| 2026-06-05 12:00 |
19:55:37.19 |
-13:13:43.0 |
HIP 98107 |
11.84 |
| 2026-06-06 00:00 |
19:55:29.82 |
-13:13:59.0 |
HIP 98107 |
13.19 |
| 2026-06-06 12:00 |
19:55:22.35 |
-13:14:15.4 |
HIP 98107 |
14.66 |
| 2026-06-07 00:00 |
19:55:14.77 |
-13:14:32.3 |
HIP 98107 |
16.23 |
| 2026-06-07 12:00 |
19:55:07.09 |
-13:14:49.7 |
HIP 98107 |
17.88 |
| 2026-06-08 00:00 |
19:54:59.30 |
-13:15:07.6 |
HIP 98107 |
19.59 |
| 2026-06-08 12:00 |
19:54:51.41 |
-13:15:25.9 |
HIP 98107 |
21.36 |
| 2026-06-09 00:00 |
19:54:43.41 |
-13:15:44.8 |
HIP 98107 |
23.18 |
| 2026-06-09 12:00 |
19:54:35.32 |
-13:16:04.1 |
HIP 98107 |
25.04 |
| 2026-06-10 00:00 |
19:54:27.12 |
-13:16:23.9 |
HIP 98107 |
26.95 |
| 2026-06-10 12:00 |
19:54:18.82 |
-13:16:44.2 |
HIP 98107 |
28.90 |
| 2026-06-11 00:00 |
19:54:10.42 |
-13:17:04.9 |
HIP 98107 |
30.88 |
| 2026-06-11 12:00 |
19:54:01.92 |
-13:17:26.1 |
HIP 98107 |
32.89 |
| 2026-06-12 00:00 |
19:53:53.33 |
-13:17:47.8 |
HIP 98014 |
34.04 |
| 2026-06-12 12:00 |
19:53:44.64 |
-13:18:10.0 |
HIP 97739 |
33.31 |
| 2026-06-13 00:00 |
19:53:35.85 |
-13:18:32.7 |
HIP 97739 |
31.66 |
| 2026-06-13 12:00 |
19:53:26.97 |
-13:18:55.8 |
HIP 97739 |
30.05 |
| 2026-06-14 00:00 |
19:53:17.99 |
-13:19:19.4 |
HIP 97739 |
28.52 |
| 2026-06-14 12:00 |
19:53:08.92 |
-13:19:43.4 |
HIP 97739 |
27.06 |
| 2026-06-15 00:00 |
19:52:59.76 |
-13:20:08.0 |
HIP 97739 |
25.71 |
| 2026-06-15 12:00 |
19:52:50.51 |
-13:20:33.0 |
HIP 97739 |
24.48 |
| 2026-06-16 00:00 |
19:52:41.17 |
-13:20:58.4 |
HIP 97739 |
23.41 |
| 2026-06-16 12:00 |
19:52:31.74 |
-13:21:24.3 |
HIP 97739 |
22.52 |
| 2026-06-17 00:00 |
19:52:22.22 |
-13:21:50.7 |
HIP 97739 |
21.85 |
| 2026-06-17 12:00 |
19:52:12.62 |
-13:22:17.6 |
HIP 97739 |
21.41 |
| 2026-06-18 00:00 |
19:52:02.93 |
-13:22:44.8 |
HIP 97739 |
21.24 |
| 2026-06-18 12:00 |
19:51:53.16 |
-13:23:12.6 |
HIP 97739 |
21.34 |
| 2026-06-19 00:00 |
19:51:43.31 |
-13:23:40.8 |
HIP 97739 |
21.73 |
| 2026-06-19 12:00 |
19:51:33.37 |
-13:24:09.4 |
HIP 97739 |
22.38 |
| 2026-06-20 00:00 |
19:51:23.36 |
-13:24:38.5 |
HIP 97739 |
23.29 |
| 2026-06-20 12:00 |
19:51:13.27 |
-13:25:08.0 |
HIP 97739 |
24.43 |
| 2026-06-21 00:00 |
19:51:03.10 |
-13:25:37.9 |
HIP 97739 |
25.79 |
| 2026-06-21 12:00 |
19:50:52.86 |
-13:26:08.3 |
HIP 97739 |
27.32 |
| 2026-06-22 00:00 |
19:50:42.54 |
-13:26:39.1 |
HIP 97739 |
29.01 |