| 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) |
| 2026-05-12 00:00 |
19:25:52.98 |
+19:57:23.6 |
HIP 95582 |
9.25 |
| 2026-05-12 12:00 |
19:25:41.84 |
+19:59:00.8 |
HIP 95560 |
10.07 |
| 2026-05-13 00:00 |
19:25:30.59 |
+20:00:37.2 |
HIP 95560 |
11.31 |
| 2026-05-13 12:00 |
19:25:19.23 |
+20:02:13.0 |
HIP 95432 |
10.07 |
| 2026-05-14 00:00 |
19:25:07.76 |
+20:03:48.0 |
HIP 95432 |
9.25 |
| 2026-05-14 12:00 |
19:24:56.19 |
+20:05:22.3 |
HIP 95432 |
9.43 |
| 2026-05-15 00:00 |
19:24:44.50 |
+20:06:55.8 |
HIP 95432 |
10.57 |
| 2026-05-15 12:00 |
19:24:32.71 |
+20:08:28.6 |
HIP 95432 |
12.42 |
| 2026-05-16 00:00 |
19:24:20.81 |
+20:10:00.6 |
HIP 95340 |
9.87 |
| 2026-05-16 12:00 |
19:24:08.81 |
+20:11:31.8 |
HIP 95340 |
6.72 |
| 2026-05-17 00:00 |
19:23:56.70 |
+20:13:02.2 |
HIP 95340 |
3.64 |
| 2026-05-17 12:00 |
19:23:44.48 |
+20:14:31.8 |
HIP 95340 |
1.45 |
| 2026-05-18 00:00 |
19:23:32.16 |
+20:16:00.6 |
HIP 95340 |
3.47 |
| 2026-05-18 12:00 |
19:23:19.74 |
+20:17:28.6 |
HIP 95291 |
1.94 |
| 2026-05-19 00:00 |
19:23:07.21 |
+20:18:55.7 |
HIP 95291 |
2.55 |
| 2026-05-19 12:00 |
19:22:54.58 |
+20:20:22.0 |
HIP 95291 |
5.55 |
| 2026-05-20 00:00 |
19:22:41.85 |
+20:21:47.5 |
HIP 95291 |
8.77 |
| 2026-05-20 12:00 |
19:22:29.02 |
+20:23:12.0 |
HIP 95291 |
12.05 |
| 2026-05-21 00:00 |
19:22:16.09 |
+20:24:35.7 |
HIP 95291 |
15.36 |
| 2026-05-21 12:00 |
19:22:03.06 |
+20:25:58.5 |
HIP 95291 |
18.70 |
| 2026-05-22 00:00 |
19:21:49.94 |
+20:27:20.5 |
HIP 95291 |
22.04 |
| 2026-05-22 12:00 |
19:21:36.71 |
+20:28:41.5 |
HIP 95291 |
25.41 |
| 2026-05-23 00:00 |
19:21:23.39 |
+20:30:01.6 |
HIP 95047 |
26.29 |
| 2026-05-23 12:00 |
19:21:09.98 |
+20:31:20.9 |
HIP 95047 |
23.52 |
| 2026-05-24 00:00 |
19:20:56.47 |
+20:32:39.2 |
HIP 95047 |
20.93 |
| 2026-05-24 12:00 |
19:20:42.86 |
+20:33:56.5 |
HIP 95047 |
18.63 |
| 2026-05-25 00:00 |
19:20:29.17 |
+20:35:12.9 |
HIP 95047 |
16.72 |
| 2026-05-25 12:00 |
19:20:15.38 |
+20:36:28.4 |
HIP 95047 |
15.39 |
| 2026-05-26 00:00 |
19:20:01.50 |
+20:37:43.0 |
HIP 95047 |
14.78 |
| 2026-05-26 12:00 |
19:19:47.53 |
+20:38:56.5 |
HIP 95047 |
15.00 |
| 2026-05-27 00:00 |
19:19:33.47 |
+20:40:09.1 |
HIP 95047 |
16.02 |
| 2026-05-27 12:00 |
19:19:19.32 |
+20:41:20.8 |
HIP 95047 |
17.71 |
| 2026-05-28 00:00 |
19:19:05.09 |
+20:42:31.4 |
HIP 95047 |
19.92 |
| 2026-05-28 12:00 |
19:18:50.77 |
+20:43:41.1 |
HIP 95047 |
22.48 |
| 2026-05-29 00:00 |
19:18:36.36 |
+20:44:49.7 |
HIP 95047 |
25.31 |
| 2026-05-29 12:00 |
19:18:21.87 |
+20:45:57.4 |
HIP 94759 |
24.22 |
| 2026-05-30 00:00 |
19:18:07.29 |
+20:47:04.0 |
HIP 94759 |
22.01 |
| 2026-05-30 12:00 |
19:17:52.64 |
+20:48:09.6 |
HIP 94759 |
20.17 |
| 2026-05-31 00:00 |
19:17:37.90 |
+20:49:14.2 |
HIP 94759 |
18.82 |
| 2026-05-31 12:00 |
19:17:23.07 |
+20:50:17.8 |
HIP 94759 |
18.08 |
| 2026-06-01 00:00 |
19:17:08.17 |
+20:51:20.3 |
HIP 94759 |
18.04 |
| 2026-06-01 12:00 |
19:16:53.19 |
+20:52:21.8 |
HIP 94759 |
18.69 |
| 2026-06-02 00:00 |
19:16:38.13 |
+20:53:22.2 |
HIP 94759 |
19.99 |