| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
06:46:56.92 |
+27:00:58.2 |
HIP 32518 |
27.47 |
| 2026-06-03 00:00 |
06:47:05.05 |
+27:01:03.4 |
HIP 32518 |
27.41 |
| 2026-06-03 12:00 |
06:47:13.20 |
+27:01:08.7 |
HIP 32518 |
27.47 |
| 2026-06-04 00:00 |
06:47:21.39 |
+27:01:13.9 |
HIP 32689 |
26.27 |
| 2026-06-04 12:00 |
06:47:29.60 |
+27:01:19.2 |
HIP 32689 |
24.56 |
| 2026-06-05 00:00 |
06:47:37.85 |
+27:01:24.4 |
HIP 32689 |
22.87 |
| 2026-06-05 12:00 |
06:47:46.12 |
+27:01:29.6 |
HIP 32689 |
21.18 |
| 2026-06-06 00:00 |
06:47:54.42 |
+27:01:34.8 |
HIP 32689 |
19.53 |
| 2026-06-06 12:00 |
06:48:02.75 |
+27:01:40.0 |
HIP 32689 |
17.90 |
| 2026-06-07 00:00 |
06:48:11.11 |
+27:01:45.2 |
HIP 32689 |
16.33 |
| 2026-06-07 12:00 |
06:48:19.49 |
+27:01:50.4 |
HIP 32689 |
14.81 |
| 2026-06-08 00:00 |
06:48:27.90 |
+27:01:55.6 |
HIP 32689 |
13.37 |
| 2026-06-08 12:00 |
06:48:36.34 |
+27:02:00.8 |
HIP 32689 |
12.06 |
| 2026-06-09 00:00 |
06:48:44.80 |
+27:02:05.9 |
HIP 32689 |
10.91 |
| 2026-06-09 12:00 |
06:48:53.29 |
+27:02:11.1 |
HIP 32689 |
9.98 |
| 2026-06-10 00:00 |
06:49:01.80 |
+27:02:16.3 |
HIP 32689 |
9.35 |
| 2026-06-10 12:00 |
06:49:10.33 |
+27:02:21.5 |
HIP 32689 |
9.07 |
| 2026-06-11 00:00 |
06:49:18.89 |
+27:02:26.6 |
HIP 32689 |
9.19 |
| 2026-06-11 12:00 |
06:49:27.47 |
+27:02:31.8 |
HIP 32777 |
8.13 |
| 2026-06-12 00:00 |
06:49:36.07 |
+27:02:37.0 |
HIP 32777 |
6.35 |
| 2026-06-12 12:00 |
06:49:44.69 |
+27:02:42.2 |
HIP 32777 |
4.68 |
| 2026-06-13 00:00 |
06:49:53.34 |
+27:02:47.3 |
HIP 32777 |
3.28 |
| 2026-06-13 12:00 |
06:50:02.01 |
+27:02:52.5 |
HIP 32777 |
2.67 |
| 2026-06-14 00:00 |
06:50:10.69 |
+27:02:57.7 |
HIP 32777 |
3.30 |
| 2026-06-14 12:00 |
06:50:19.40 |
+27:03:02.9 |
HIP 32777 |
4.72 |
| 2026-06-15 00:00 |
06:50:28.12 |
+27:03:08.1 |
HIP 32777 |
6.42 |
| 2026-06-15 12:00 |
06:50:36.86 |
+27:03:13.3 |
HIP 32777 |
8.23 |
| 2026-06-16 00:00 |
06:50:45.62 |
+27:03:18.5 |
HIP 32777 |
10.10 |
| 2026-06-16 12:00 |
06:50:54.39 |
+27:03:23.7 |
HIP 32777 |
11.99 |
| 2026-06-17 00:00 |
06:51:03.19 |
+27:03:29.0 |
HIP 32777 |
13.91 |
| 2026-06-17 12:00 |
06:51:11.99 |
+27:03:34.2 |
HIP 32777 |
15.84 |
| 2026-06-18 00:00 |
06:51:20.82 |
+27:03:39.4 |
HIP 32777 |
17.78 |
| 2026-06-18 12:00 |
06:51:29.65 |
+27:03:44.7 |
HIP 32777 |
19.73 |
| 2026-06-19 00:00 |
06:51:38.50 |
+27:03:50.0 |
HIP 32777 |
21.69 |
| 2026-06-19 12:00 |
06:51:47.37 |
+27:03:55.3 |
HIP 32777 |
23.65 |
| 2026-06-20 00:00 |
06:51:56.24 |
+27:04:00.6 |
HIP 32922 |
24.77 |
| 2026-06-20 12:00 |
06:52:05.13 |
+27:04:05.9 |
HIP 32922 |
25.34 |
| 2026-06-21 00:00 |
06:52:14.03 |
+27:04:11.2 |
HIP 32922 |
26.05 |
| 2026-06-21 12:00 |
06:52:22.95 |
+27:04:16.6 |
HIP 32922 |
26.89 |
| 2026-06-22 00:00 |
06:52:31.87 |
+27:04:22.0 |
HIP 33149 |
25.41 |