| Parameter |
Value |
| Designation |
490P/ATLAS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-06-22T16:00:54.581760Z |
| Orbit solution date (soln_date, UTC) |
2024-12-03T17:12:47Z |
| Obs used |
368 |
| NEO |
Yes |
| M1 |
20.500 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-06-29T13:56:52.051200Z |
| Discovery magnitude (MPC) |
18.36 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-12-01.0000000 |
| e |
0.64849913 |
| q (au) |
1.063456 |
| a (au) |
3.025473 |
| i (deg) |
12.281885 |
| Ω (om, deg) |
307.601988 |
| ω (w, deg) |
332.525414 |
| M (ma, deg) |
30.215976 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.669 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.669 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.735 |
| k |
0.975 |
| 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) |
| 2026-07-29 00:00 |
06:07:45.83 |
+30:36:43.2 |
HIP 29050 |
4.50 |
| 2026-07-29 12:00 |
06:08:12.93 |
+30:36:46.1 |
HIP 29125 |
4.46 |
| 2026-07-30 00:00 |
06:08:39.94 |
+30:36:49.0 |
HIP 29125 |
3.16 |
| 2026-07-30 12:00 |
06:09:06.86 |
+30:36:51.8 |
HIP 29125 |
8.21 |
| 2026-07-31 00:00 |
06:09:33.70 |
+30:36:54.6 |
HIP 29273 |
9.62 |
| 2026-07-31 12:00 |
06:10:00.46 |
+30:36:57.4 |
HIP 29273 |
4.99 |
| 2026-08-01 00:00 |
06:10:27.13 |
+30:37:00.1 |
HIP 29273 |
4.85 |
| 2026-08-01 12:00 |
06:10:53.72 |
+30:37:02.8 |
HIP 29273 |
9.36 |
| 2026-08-02 00:00 |
06:11:20.21 |
+30:37:05.4 |
HIP 29273 |
14.72 |
| 2026-08-02 12:00 |
06:11:46.62 |
+30:37:08.0 |
HIP 29273 |
20.25 |
| 2026-08-03 00:00 |
06:12:12.94 |
+30:37:10.6 |
HIP 29463 |
18.53 |
| 2026-08-03 12:00 |
06:12:39.17 |
+30:37:13.2 |
HIP 29463 |
18.39 |
| 2026-08-04 00:00 |
06:13:05.30 |
+30:37:15.7 |
HIP 29463 |
19.91 |
| 2026-08-04 12:00 |
06:13:31.35 |
+30:37:18.3 |
HIP 29617 |
15.78 |
| 2026-08-05 00:00 |
06:13:57.30 |
+30:37:20.8 |
HIP 29617 |
11.84 |
| 2026-08-05 12:00 |
06:14:23.16 |
+30:37:23.3 |
HIP 29617 |
9.66 |
| 2026-08-06 00:00 |
06:14:48.93 |
+30:37:25.8 |
HIP 29617 |
10.40 |
| 2026-08-06 12:00 |
06:15:14.60 |
+30:37:28.3 |
HIP 29742 |
12.26 |
| 2026-08-07 00:00 |
06:15:40.17 |
+30:37:30.8 |
HIP 29742 |
9.80 |
| 2026-08-07 12:00 |
06:16:05.65 |
+30:37:33.3 |
HIP 29742 |
10.10 |
| 2026-08-08 00:00 |
06:16:31.02 |
+30:37:35.7 |
HIP 29742 |
12.95 |
| 2026-08-08 12:00 |
06:16:56.30 |
+30:37:38.2 |
HIP 29742 |
17.10 |
| 2026-08-09 00:00 |
06:17:21.48 |
+30:37:40.8 |
HIP 29742 |
21.80 |
| 2026-08-09 12:00 |
06:17:46.55 |
+30:37:43.3 |
HIP 29742 |
26.75 |
| 2026-08-10 00:00 |
06:18:11.53 |
+30:37:45.8 |
HIP 30115 |
30.76 |
| 2026-08-10 12:00 |
06:18:36.39 |
+30:37:48.4 |
HIP 30115 |
26.31 |
| 2026-08-11 00:00 |
06:19:01.16 |
+30:37:51.0 |
HIP 30115 |
22.28 |
| 2026-08-11 12:00 |
06:19:25.82 |
+30:37:53.6 |
HIP 30115 |
18.92 |
| 2026-08-12 00:00 |
06:19:50.37 |
+30:37:56.2 |
HIP 30115 |
16.62 |
| 2026-08-12 12:00 |
06:20:14.81 |
+30:37:58.9 |
HIP 30115 |
15.82 |
| 2026-08-13 00:00 |
06:20:39.14 |
+30:38:01.6 |
HIP 30115 |
16.72 |
| 2026-08-13 12:00 |
06:21:03.37 |
+30:38:04.4 |
HIP 30115 |
19.06 |
| 2026-08-14 00:00 |
06:21:27.48 |
+30:38:07.2 |
HIP 30115 |
22.38 |
| 2026-08-14 12:00 |
06:21:51.48 |
+30:38:10.0 |
HIP 30309 |
20.17 |
| 2026-08-15 00:00 |
06:22:15.36 |
+30:38:12.9 |
HIP 30309 |
18.71 |
| 2026-08-15 12:00 |
06:22:39.13 |
+30:38:15.8 |
HIP 30309 |
18.60 |
| 2026-08-16 00:00 |
06:23:02.79 |
+30:38:18.8 |
HIP 30309 |
19.83 |
| 2026-08-16 12:00 |
06:23:26.33 |
+30:38:21.9 |
HIP 30309 |
22.18 |
| 2026-08-17 00:00 |
06:23:49.75 |
+30:38:25.0 |
HIP 30309 |
25.31 |
| 2026-08-17 12:00 |
06:24:13.06 |
+30:38:28.2 |
HIP 30609 |
24.42 |
| 2026-08-18 00:00 |
06:24:36.24 |
+30:38:31.5 |
HIP 30609 |
19.88 |
| 2026-08-18 12:00 |
06:24:59.31 |
+30:38:34.8 |
HIP 30609 |
15.62 |
| 2026-08-19 00:00 |
06:25:22.25 |
+30:38:38.3 |
HIP 30609 |
11.95 |