| Parameter |
Value |
| Designation |
C/2019 Y1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-03-15T13:31:42.720960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:34:02Z |
| Obs used |
1010 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
21.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-12-16T05:25:48.432000Z |
| Discovery magnitude (MPC) |
17.90 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-04-12.0000000 |
| e |
0.99650778 |
| q (au) |
0.837824 |
| a (au) |
239.911751 |
| i (deg) |
73.348136 |
| Ω (om, deg) |
31.366339 |
| ω (w, deg) |
57.498171 |
| M (ma, deg) |
0.007277 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.361 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.361 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2019-12-16 |
2020-01-18 |
+16.5581 |
-1.194 |
| 2020-01-18 |
2020-03-15 |
+7.5651 |
-0.659 |
| 2020-03-15 |
2020-07-12 |
+2.0051 |
-1.445 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
13:38:29.93 |
-46:10:24.3 |
HIP 66556 |
13.26 |
| 2026-05-12 12:00 |
13:38:21.49 |
-46:09:39.0 |
HIP 66556 |
14.20 |
| 2026-05-13 00:00 |
13:38:13.09 |
-46:08:53.4 |
HIP 66556 |
15.26 |
| 2026-05-13 12:00 |
13:38:04.73 |
-46:08:07.4 |
HIP 66484 |
15.43 |
| 2026-05-14 00:00 |
13:37:56.41 |
-46:07:21.0 |
HIP 66484 |
14.45 |
| 2026-05-14 12:00 |
13:37:48.14 |
-46:06:34.2 |
HIP 66484 |
13.60 |
| 2026-05-15 00:00 |
13:37:39.91 |
-46:05:47.1 |
HIP 66484 |
12.89 |
| 2026-05-15 12:00 |
13:37:31.72 |
-46:04:59.6 |
HIP 66484 |
12.35 |
| 2026-05-16 00:00 |
13:37:23.58 |
-46:04:11.8 |
HIP 66484 |
12.00 |
| 2026-05-16 12:00 |
13:37:15.49 |
-46:03:23.7 |
HIP 66484 |
11.86 |
| 2026-05-17 00:00 |
13:37:07.44 |
-46:02:35.2 |
HIP 66484 |
11.93 |
| 2026-05-17 12:00 |
13:36:59.44 |
-46:01:46.4 |
HIP 66484 |
12.20 |
| 2026-05-18 00:00 |
13:36:51.48 |
-46:00:57.2 |
HIP 66484 |
12.67 |
| 2026-05-18 12:00 |
13:36:43.57 |
-46:00:07.8 |
HIP 66484 |
13.30 |
| 2026-05-19 00:00 |
13:36:35.72 |
-45:59:18.0 |
HIP 66484 |
14.08 |
| 2026-05-19 12:00 |
13:36:27.91 |
-45:58:27.9 |
HIP 66484 |
14.98 |
| 2026-05-20 00:00 |
13:36:20.15 |
-45:57:37.6 |
HIP 66484 |
15.98 |
| 2026-05-20 12:00 |
13:36:12.44 |
-45:56:46.9 |
HIP 66484 |
17.06 |
| 2026-05-21 00:00 |
13:36:04.78 |
-45:55:55.9 |
HIP 66484 |
18.21 |
| 2026-05-21 12:00 |
13:35:57.18 |
-45:55:04.7 |
HIP 66484 |
19.40 |
| 2026-05-22 00:00 |
13:35:49.63 |
-45:54:13.2 |
HIP 66484 |
20.64 |
| 2026-05-22 12:00 |
13:35:42.13 |
-45:53:21.4 |
HIP 66484 |
21.92 |
| 2026-05-23 00:00 |
13:35:34.68 |
-45:52:29.4 |
HIP 66484 |
23.22 |
| 2026-05-23 12:00 |
13:35:27.29 |
-45:51:37.1 |
HIP 66484 |
24.54 |
| 2026-05-24 00:00 |
13:35:19.95 |
-45:50:44.5 |
HIP 66484 |
25.88 |
| 2026-05-24 12:00 |
13:35:12.67 |
-45:49:51.7 |
HIP 66484 |
27.23 |
| 2026-05-25 00:00 |
13:35:05.44 |
-45:48:58.6 |
HIP 66105 |
27.36 |
| 2026-05-25 12:00 |
13:34:58.27 |
-45:48:05.4 |
HIP 66105 |
25.83 |
| 2026-05-26 00:00 |
13:34:51.15 |
-45:47:11.9 |
HIP 66105 |
24.30 |
| 2026-05-26 12:00 |
13:34:44.10 |
-45:46:18.1 |
HIP 66105 |
22.78 |
| 2026-05-27 00:00 |
13:34:37.09 |
-45:45:24.2 |
HIP 66105 |
21.27 |
| 2026-05-27 12:00 |
13:34:30.15 |
-45:44:30.0 |
HIP 66105 |
19.76 |
| 2026-05-28 00:00 |
13:34:23.26 |
-45:43:35.6 |
HIP 66105 |
18.25 |
| 2026-05-28 12:00 |
13:34:16.44 |
-45:42:41.0 |
HIP 66105 |
16.76 |
| 2026-05-29 00:00 |
13:34:09.67 |
-45:41:46.3 |
HIP 66105 |
15.27 |
| 2026-05-29 12:00 |
13:34:02.96 |
-45:40:51.3 |
HIP 66105 |
13.78 |
| 2026-05-30 00:00 |
13:33:56.31 |
-45:39:56.2 |
HIP 66105 |
12.30 |
| 2026-05-30 12:00 |
13:33:49.72 |
-45:39:00.8 |
HIP 66105 |
10.83 |
| 2026-05-31 00:00 |
13:33:43.19 |
-45:38:05.3 |
HIP 66105 |
9.36 |
| 2026-05-31 12:00 |
13:33:36.72 |
-45:37:09.7 |
HIP 66105 |
7.90 |
| 2026-06-01 00:00 |
13:33:30.32 |
-45:36:13.8 |
HIP 66105 |
6.44 |
| 2026-06-01 12:00 |
13:33:23.97 |
-45:35:17.8 |
HIP 66105 |
5.00 |
| 2026-06-02 00:00 |
13:33:17.69 |
-45:34:21.7 |
HIP 66105 |
3.56 |