| Parameter |
Value |
| Designation |
C/2021 X1 (Maury-Attard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-05-27T07:30:21.781440Z |
| Orbit solution date (soln_date, UTC) |
2024-10-05T23:12:24Z |
| Obs used |
2855 |
| NEO |
- |
| M1 |
8.800 |
| K1 |
8.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-12-02T07:46:33.600000Z |
| Discovery magnitude (MPC) |
19.00 G |
| Discovery observatory (MPC) |
W94 · MAPS, San Pedro de Atacama |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-07-16.0000000 |
| e |
1.00132476 |
| q (au) |
3.233578 |
| a (au) |
-2440.886866 |
| i (deg) |
140.111737 |
| Ω (om, deg) |
10.591202 |
| ω (w, deg) |
334.595699 |
| M (ma, deg) |
0.000406 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.700 + 3.519\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.700 |
| n |
3.519 |
| gf |
0.988 |
| gb |
-0.977 |
| k |
1.000 |
| δ90 |
9.948 |
| 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 |
| 2021-12-02 |
2022-11-02 |
+4.7011 |
-3.916 |
| 2022-11-02 |
2023-03-19 |
-16.6535 |
+8.611 |
| 2023-06-17 |
2024-09-27 |
+1.8795 |
-0.958 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
19:34:39.55 |
+16:55:46.3 |
HIP 96294 |
17.33 |
| 2026-03-26 12:00 |
19:34:39.32 |
+16:57:46.7 |
HIP 96377 |
17.27 |
| 2026-03-27 00:00 |
19:34:38.98 |
+16:59:47.3 |
HIP 96377 |
16.42 |
| 2026-03-27 12:00 |
19:34:38.53 |
+17:01:48.1 |
HIP 96377 |
15.80 |
| 2026-03-28 00:00 |
19:34:37.97 |
+17:03:49.0 |
HIP 96377 |
15.45 |
| 2026-03-28 12:00 |
19:34:37.30 |
+17:05:50.1 |
HIP 96377 |
15.39 |
| 2026-03-29 00:00 |
19:34:36.52 |
+17:07:51.3 |
HIP 96377 |
15.62 |
| 2026-03-29 12:00 |
19:34:35.64 |
+17:09:52.6 |
HIP 96208 |
15.13 |
| 2026-03-30 00:00 |
19:34:34.64 |
+17:11:54.0 |
HIP 96208 |
13.71 |
| 2026-03-30 12:00 |
19:34:33.53 |
+17:13:55.6 |
HIP 96208 |
12.43 |
| 2026-03-31 00:00 |
19:34:32.31 |
+17:15:57.3 |
HIP 96208 |
11.36 |
| 2026-03-31 12:00 |
19:34:30.98 |
+17:17:59.1 |
HIP 96208 |
10.55 |
| 2026-04-01 00:00 |
19:34:29.54 |
+17:20:00.9 |
HIP 96208 |
10.07 |
| 2026-04-01 12:00 |
19:34:27.99 |
+17:22:02.9 |
HIP 96208 |
9.98 |
| 2026-04-02 00:00 |
19:34:26.32 |
+17:24:04.9 |
HIP 96208 |
10.29 |
| 2026-04-02 12:00 |
19:34:24.55 |
+17:26:07.0 |
HIP 96208 |
10.96 |
| 2026-04-03 00:00 |
19:34:22.66 |
+17:28:09.1 |
HIP 96208 |
11.94 |
| 2026-04-03 12:00 |
19:34:20.65 |
+17:30:11.3 |
HIP 96208 |
13.17 |
| 2026-04-04 00:00 |
19:34:18.54 |
+17:32:13.6 |
HIP 96208 |
14.58 |
| 2026-04-04 12:00 |
19:34:16.31 |
+17:34:15.9 |
HIP 96208 |
16.13 |
| 2026-04-05 00:00 |
19:34:13.96 |
+17:36:18.2 |
HIP 96208 |
17.79 |
| 2026-04-05 12:00 |
19:34:11.50 |
+17:38:20.5 |
HIP 96208 |
19.53 |
| 2026-04-06 00:00 |
19:34:08.93 |
+17:40:22.9 |
HIP 96268 |
19.08 |
| 2026-04-06 12:00 |
19:34:06.24 |
+17:42:25.2 |
HIP 96268 |
17.29 |
| 2026-04-07 00:00 |
19:34:03.44 |
+17:44:27.5 |
HIP 96268 |
15.61 |
| 2026-04-07 12:00 |
19:34:00.52 |
+17:46:29.9 |
HIP 96268 |
14.06 |
| 2026-04-08 00:00 |
19:33:57.48 |
+17:48:32.2 |
HIP 96268 |
12.71 |
| 2026-04-08 12:00 |
19:33:54.33 |
+17:50:34.4 |
HIP 96268 |
11.63 |
| 2026-04-09 00:00 |
19:33:51.06 |
+17:52:36.7 |
HIP 96268 |
10.90 |
| 2026-04-09 12:00 |
19:33:47.68 |
+17:54:38.9 |
HIP 96268 |
10.60 |
| 2026-04-10 00:00 |
19:33:44.18 |
+17:56:41.0 |
HIP 96268 |
10.78 |
| 2026-04-10 12:00 |
19:33:40.56 |
+17:58:43.0 |
HIP 96268 |
11.42 |
| 2026-04-11 00:00 |
19:33:36.82 |
+18:00:45.0 |
HIP 96268 |
12.44 |
| 2026-04-11 12:00 |
19:33:32.97 |
+18:02:46.9 |
HIP 96268 |
13.78 |
| 2026-04-12 00:00 |
19:33:29.00 |
+18:04:48.7 |
HIP 96268 |
15.35 |
| 2026-04-12 12:00 |
19:33:24.90 |
+18:06:50.4 |
HIP 96268 |
17.10 |
| 2026-04-13 00:00 |
19:33:20.70 |
+18:08:52.0 |
HIP 96280 |
18.27 |
| 2026-04-13 12:00 |
19:33:16.37 |
+18:10:53.4 |
HIP 96280 |
19.52 |
| 2026-04-14 00:00 |
19:33:11.92 |
+18:12:54.7 |
HIP 96280 |
20.97 |
| 2026-04-14 12:00 |
19:33:07.35 |
+18:14:55.9 |
HIP 96280 |
22.59 |
| 2026-04-15 00:00 |
19:33:02.67 |
+18:16:56.9 |
HIP 96280 |
24.34 |
| 2026-04-15 12:00 |
19:32:57.86 |
+18:18:57.8 |
HIP 96191 |
24.77 |
| 2026-04-16 00:00 |
19:32:52.94 |
+18:20:58.5 |
HIP 96191 |
23.33 |