| Parameter |
Value |
| Designation |
C/2021 E3 (ZTF) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-06-11T21:41:58.525440Z |
| Orbit solution date (soln_date, UTC) |
2026-03-11T21:13:02Z |
| Obs used |
1491 |
| NEO |
- |
| M1 |
11.100 |
| K1 |
5.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-03-09T12:41:11.904000Z |
| Discovery magnitude (MPC) |
19.60 r |
| Discovery observatory (MPC) |
I41 · Palomar Mountain–ZTF |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-02-28.0000000 |
| e |
1.00086348 |
| q (au) |
1.777410 |
| a (au) |
-2058.429778 |
| i (deg) |
112.555637 |
| Ω (om, deg) |
104.468418 |
| ω (w, deg) |
228.845737 |
| M (ma, deg) |
-0.001097 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.650 + 3.246\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.650 |
| n |
3.246 |
| gf |
1.000 |
| gb |
-0.558 |
| k |
0.800 |
| 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 |
| 2021-03-09 |
2022-06-10 |
+4.2489 |
-2.716 |
| 2022-06-16 |
2022-11-11 |
+10.7149 |
-4.279 |
| 2022-11-11 |
2024-01-13 |
-0.3955 |
+0.570 |
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 |
06:41:44.43 |
+26:56:53.8 |
HIP 32044 |
8.01 |
| 2026-05-12 12:00 |
06:41:50.71 |
+26:57:00.1 |
HIP 32044 |
8.09 |
| 2026-05-13 00:00 |
06:41:57.04 |
+26:57:06.4 |
HIP 32044 |
8.41 |
| 2026-05-13 12:00 |
06:42:03.43 |
+26:57:12.6 |
HIP 32044 |
8.96 |
| 2026-05-14 00:00 |
06:42:09.87 |
+26:57:18.8 |
HIP 32044 |
9.69 |
| 2026-05-14 12:00 |
06:42:16.36 |
+26:57:24.9 |
HIP 32044 |
10.58 |
| 2026-05-15 00:00 |
06:42:22.91 |
+26:57:31.0 |
HIP 32044 |
11.60 |
| 2026-05-15 12:00 |
06:42:29.51 |
+26:57:37.1 |
HIP 32194 |
10.16 |
| 2026-05-16 00:00 |
06:42:36.16 |
+26:57:43.1 |
HIP 32194 |
8.70 |
| 2026-05-16 12:00 |
06:42:42.87 |
+26:57:49.1 |
HIP 32194 |
7.25 |
| 2026-05-17 00:00 |
06:42:49.62 |
+26:57:55.1 |
HIP 32194 |
5.81 |
| 2026-05-17 12:00 |
06:42:56.42 |
+26:58:01.0 |
HIP 32194 |
4.39 |
| 2026-05-18 00:00 |
06:43:03.28 |
+26:58:06.9 |
HIP 32194 |
3.08 |
| 2026-05-18 12:00 |
06:43:10.18 |
+26:58:12.8 |
HIP 32194 |
2.07 |
| 2026-05-19 00:00 |
06:43:17.13 |
+26:58:18.6 |
HIP 32194 |
1.97 |
| 2026-05-19 12:00 |
06:43:24.13 |
+26:58:24.4 |
HIP 32194 |
2.88 |
| 2026-05-20 00:00 |
06:43:31.17 |
+26:58:30.2 |
HIP 32194 |
4.21 |
| 2026-05-20 12:00 |
06:43:38.26 |
+26:58:36.0 |
HIP 32194 |
5.67 |
| 2026-05-21 00:00 |
06:43:45.39 |
+26:58:41.7 |
HIP 32194 |
7.19 |
| 2026-05-21 12:00 |
06:43:52.58 |
+26:58:47.4 |
HIP 32194 |
8.75 |
| 2026-05-22 00:00 |
06:43:59.80 |
+26:58:53.1 |
HIP 32194 |
10.33 |
| 2026-05-22 12:00 |
06:44:07.07 |
+26:58:58.7 |
HIP 32194 |
11.93 |
| 2026-05-23 00:00 |
06:44:14.38 |
+26:59:04.4 |
HIP 32194 |
13.54 |
| 2026-05-23 12:00 |
06:44:21.74 |
+26:59:10.0 |
HIP 32194 |
15.17 |
| 2026-05-24 00:00 |
06:44:29.13 |
+26:59:15.6 |
HIP 32194 |
16.81 |
| 2026-05-24 12:00 |
06:44:36.57 |
+26:59:21.1 |
HIP 32194 |
18.46 |
| 2026-05-25 00:00 |
06:44:44.05 |
+26:59:26.7 |
HIP 32194 |
20.12 |
| 2026-05-25 12:00 |
06:44:51.57 |
+26:59:32.2 |
HIP 32194 |
21.79 |
| 2026-05-26 00:00 |
06:44:59.13 |
+26:59:37.7 |
HIP 32194 |
23.47 |
| 2026-05-26 12:00 |
06:45:06.73 |
+26:59:43.2 |
HIP 32194 |
25.16 |
| 2026-05-27 00:00 |
06:45:14.36 |
+26:59:48.6 |
HIP 32194 |
26.86 |
| 2026-05-27 12:00 |
06:45:22.04 |
+26:59:54.1 |
HIP 32194 |
28.57 |
| 2026-05-28 00:00 |
06:45:29.75 |
+26:59:59.5 |
HIP 32194 |
30.28 |
| 2026-05-28 12:00 |
06:45:37.50 |
+27:00:04.9 |
HIP 32194 |
32.01 |
| 2026-05-29 00:00 |
06:45:45.29 |
+27:00:10.3 |
HIP 32518 |
32.65 |
| 2026-05-29 12:00 |
06:45:53.11 |
+27:00:15.7 |
HIP 32518 |
31.74 |
| 2026-05-30 00:00 |
06:46:00.97 |
+27:00:21.0 |
HIP 32518 |
30.89 |
| 2026-05-30 12:00 |
06:46:08.86 |
+27:00:26.4 |
HIP 32518 |
30.12 |
| 2026-05-31 00:00 |
06:46:16.79 |
+27:00:31.7 |
HIP 32518 |
29.43 |
| 2026-05-31 12:00 |
06:46:24.75 |
+27:00:37.0 |
HIP 32518 |
28.83 |
| 2026-06-01 00:00 |
06:46:32.74 |
+27:00:42.3 |
HIP 32518 |
28.33 |
| 2026-06-01 12:00 |
06:46:40.77 |
+27:00:47.6 |
HIP 32518 |
27.93 |
| 2026-06-02 00:00 |
06:46:48.83 |
+27:00:52.9 |
HIP 32518 |
27.64 |