| 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) |
| 2026-07-29 00:00 |
19:36:08.55 |
-14:20:32.2 |
HIP 96506 |
16.05 |
| 2026-07-29 12:00 |
19:35:56.71 |
-14:21:24.8 |
HIP 96506 |
18.55 |
| 2026-07-30 00:00 |
19:35:44.90 |
-14:22:17.6 |
HIP 96506 |
21.17 |
| 2026-07-30 12:00 |
19:35:33.13 |
-14:23:10.4 |
HIP 96506 |
23.86 |
| 2026-07-31 00:00 |
19:35:21.41 |
-14:24:03.4 |
HIP 96506 |
26.61 |
| 2026-07-31 12:00 |
19:35:09.73 |
-14:24:56.4 |
HIP 96506 |
29.39 |
| 2026-08-01 00:00 |
19:34:58.09 |
-14:25:49.6 |
HIP 96506 |
32.19 |
| 2026-08-01 12:00 |
19:34:46.50 |
-14:26:42.9 |
HIP 96506 |
35.01 |
| 2026-08-02 00:00 |
19:34:34.96 |
-14:27:36.2 |
HIP 96506 |
37.83 |
| 2026-08-02 12:00 |
19:34:23.46 |
-14:28:29.7 |
HIP 96169 |
35.97 |
| 2026-08-03 00:00 |
19:34:12.02 |
-14:29:23.2 |
HIP 96169 |
33.97 |
| 2026-08-03 12:00 |
19:34:00.62 |
-14:30:16.8 |
HIP 96169 |
32.11 |
| 2026-08-04 00:00 |
19:33:49.28 |
-14:31:10.5 |
HIP 96169 |
30.42 |
| 2026-08-04 12:00 |
19:33:38.00 |
-14:32:04.3 |
HIP 96169 |
28.92 |
| 2026-08-05 00:00 |
19:33:26.77 |
-14:32:58.1 |
HIP 96105 |
27.50 |
| 2026-08-05 12:00 |
19:33:15.60 |
-14:33:52.0 |
HIP 96105 |
25.31 |
| 2026-08-06 00:00 |
19:33:04.48 |
-14:34:46.0 |
HIP 96105 |
23.27 |
| 2026-08-06 12:00 |
19:32:53.43 |
-14:35:40.0 |
HIP 96105 |
21.41 |
| 2026-08-07 00:00 |
19:32:42.44 |
-14:36:34.1 |
HIP 96105 |
19.78 |
| 2026-08-07 12:00 |
19:32:31.51 |
-14:37:28.2 |
HIP 96105 |
18.43 |
| 2026-08-08 00:00 |
19:32:20.65 |
-14:38:22.3 |
HIP 96105 |
17.44 |
| 2026-08-08 12:00 |
19:32:09.85 |
-14:39:16.5 |
HIP 96105 |
16.84 |
| 2026-08-09 00:00 |
19:31:59.12 |
-14:40:10.7 |
HIP 95974 |
16.06 |
| 2026-08-09 12:00 |
19:31:48.46 |
-14:41:05.0 |
HIP 95974 |
14.18 |
| 2026-08-10 00:00 |
19:31:37.87 |
-14:41:59.2 |
HIP 95974 |
12.62 |
| 2026-08-10 12:00 |
19:31:27.36 |
-14:42:53.5 |
HIP 95974 |
11.51 |
| 2026-08-11 00:00 |
19:31:16.91 |
-14:43:47.8 |
HIP 95974 |
10.98 |
| 2026-08-11 12:00 |
19:31:06.54 |
-14:44:42.1 |
HIP 95974 |
11.09 |
| 2026-08-12 00:00 |
19:30:56.25 |
-14:45:36.4 |
HIP 95974 |
11.82 |
| 2026-08-12 12:00 |
19:30:46.03 |
-14:46:30.7 |
HIP 95974 |
13.05 |
| 2026-08-13 00:00 |
19:30:35.90 |
-14:47:25.0 |
HIP 95974 |
14.65 |
| 2026-08-13 12:00 |
19:30:25.84 |
-14:48:19.3 |
HIP 95974 |
16.50 |
| 2026-08-14 00:00 |
19:30:15.87 |
-14:49:13.6 |
HIP 95974 |
18.52 |
| 2026-08-14 12:00 |
19:30:05.98 |
-14:50:07.8 |
HIP 95974 |
20.65 |
| 2026-08-15 00:00 |
19:29:56.17 |
-14:51:02.1 |
HIP 95974 |
22.85 |
| 2026-08-15 12:00 |
19:29:46.45 |
-14:51:56.3 |
HIP 95755 |
22.29 |
| 2026-08-16 00:00 |
19:29:36.82 |
-14:52:50.4 |
HIP 95755 |
19.93 |
| 2026-08-16 12:00 |
19:29:27.27 |
-14:53:44.5 |
HIP 95755 |
17.63 |
| 2026-08-17 00:00 |
19:29:17.82 |
-14:54:38.6 |
HIP 95755 |
15.41 |
| 2026-08-17 12:00 |
19:29:08.45 |
-14:55:32.6 |
HIP 95755 |
13.27 |
| 2026-08-18 00:00 |
19:28:59.18 |
-14:56:26.6 |
HIP 95755 |
11.28 |
| 2026-08-18 12:00 |
19:28:50.00 |
-14:57:20.5 |
HIP 95755 |
9.48 |
| 2026-08-19 00:00 |
19:28:40.91 |
-14:58:14.3 |
HIP 95755 |
8.01 |