C/2019 Y1 (ATLAS)
| 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) |
| 2026-02-03 00:00 |
14:02:29.24 |
-45:45:25.0 |
HIP 68523 |
12.20 |
| 2026-02-03 12:00 |
14:02:27.32 |
-45:46:22.1 |
HIP 68523 |
12.73 |
| 2026-02-04 00:00 |
14:02:25.32 |
-45:47:19.0 |
HIP 68523 |
13.30 |
| 2026-02-04 12:00 |
14:02:23.24 |
-45:48:15.5 |
HIP 68523 |
13.91 |
| 2026-02-05 00:00 |
14:02:21.07 |
-45:49:11.7 |
HIP 68523 |
14.55 |
| 2026-02-05 12:00 |
14:02:18.83 |
-45:50:07.5 |
HIP 68523 |
15.23 |
| 2026-02-06 00:00 |
14:02:16.50 |
-45:51:03.0 |
HIP 68523 |
15.93 |
| 2026-02-06 12:00 |
14:02:14.09 |
-45:51:58.2 |
HIP 68523 |
16.65 |
| 2026-02-07 00:00 |
14:02:11.60 |
-45:52:53.0 |
HIP 68523 |
17.39 |
| 2026-02-07 12:00 |
14:02:09.03 |
-45:53:47.5 |
HIP 68435 |
17.59 |
| 2026-02-08 00:00 |
14:02:06.38 |
-45:54:41.6 |
HIP 68435 |
17.56 |
| 2026-02-08 12:00 |
14:02:03.65 |
-45:55:35.3 |
HIP 68435 |
17.59 |
| 2026-02-09 00:00 |
14:02:00.83 |
-45:56:28.7 |
HIP 68435 |
17.65 |
| 2026-02-09 12:00 |
14:01:57.94 |
-45:57:21.7 |
HIP 68435 |
17.76 |
| 2026-02-10 00:00 |
14:01:54.96 |
-45:58:14.4 |
HIP 68435 |
17.91 |
| 2026-02-10 12:00 |
14:01:51.91 |
-45:59:06.6 |
HIP 68435 |
18.10 |
| 2026-02-11 00:00 |
14:01:48.77 |
-45:59:58.5 |
HIP 68414 |
17.37 |
| 2026-02-11 12:00 |
14:01:45.55 |
-46:00:50.0 |
HIP 68414 |
16.50 |
| 2026-02-12 00:00 |
14:01:42.25 |
-46:01:41.1 |
HIP 68414 |
15.63 |
| 2026-02-12 12:00 |
14:01:38.88 |
-46:02:31.9 |
HIP 68414 |
14.78 |
| 2026-02-13 00:00 |
14:01:35.42 |
-46:03:22.2 |
HIP 68414 |
13.94 |
| 2026-02-13 12:00 |
14:01:31.88 |
-46:04:12.1 |
HIP 68414 |
13.11 |
| 2026-02-14 00:00 |
14:01:28.26 |
-46:05:01.6 |
HIP 68414 |
12.30 |
| 2026-02-14 12:00 |
14:01:24.56 |
-46:05:50.7 |
HIP 68414 |
11.52 |
| 2026-02-15 00:00 |
14:01:20.78 |
-46:06:39.4 |
HIP 68414 |
10.77 |
| 2026-02-15 12:00 |
14:01:16.93 |
-46:07:27.6 |
HIP 68414 |
10.06 |
| 2026-02-16 00:00 |
14:01:12.99 |
-46:08:15.5 |
HIP 68414 |
9.39 |
| 2026-02-16 12:00 |
14:01:08.98 |
-46:09:02.9 |
HIP 68414 |
8.79 |
| 2026-02-17 00:00 |
14:01:04.88 |
-46:09:49.8 |
HIP 68414 |
8.26 |
| 2026-02-17 12:00 |
14:01:00.71 |
-46:10:36.4 |
HIP 68414 |
7.83 |
| 2026-02-18 00:00 |
14:00:56.46 |
-46:11:22.5 |
HIP 68414 |
7.50 |
| 2026-02-18 12:00 |
14:00:52.14 |
-46:12:08.1 |
HIP 68414 |
7.31 |
| 2026-02-19 00:00 |
14:00:47.73 |
-46:12:53.3 |
HIP 68414 |
7.25 |
| 2026-02-19 12:00 |
14:00:43.25 |
-46:13:38.0 |
HIP 68414 |
7.33 |
| 2026-02-20 00:00 |
14:00:38.69 |
-46:14:22.3 |
HIP 68414 |
7.56 |
| 2026-02-20 12:00 |
14:00:34.05 |
-46:15:06.1 |
HIP 68414 |
7.92 |
| 2026-02-21 00:00 |
14:00:29.34 |
-46:15:49.5 |
HIP 68414 |
8.39 |
| 2026-02-21 12:00 |
14:00:24.55 |
-46:16:32.4 |
HIP 68414 |
8.96 |
| 2026-02-22 00:00 |
14:00:19.69 |
-46:17:14.8 |
HIP 68414 |
9.61 |
| 2026-02-22 12:00 |
14:00:14.75 |
-46:17:56.7 |
HIP 68414 |
10.34 |
| 2026-02-23 00:00 |
14:00:09.74 |
-46:18:38.2 |
HIP 68414 |
11.11 |
| 2026-02-23 12:00 |
14:00:04.65 |
-46:19:19.2 |
HIP 68414 |
11.94 |
| 2026-02-24 00:00 |
13:59:59.49 |
-46:19:59.7 |
HIP 68414 |
12.81 |