| Parameter |
Value |
| Designation |
C/2021 T2 (Fuls) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-06-07T21:34:39.907200Z |
| Orbit solution date (soln_date, UTC) |
2023-01-14T00:13:00Z |
| Obs used |
183 |
| NEO |
- |
| M1 |
15.300 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-10-02T09:01:40.224000Z |
| Discovery magnitude (MPC) |
19.87 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-11-13.0000000 |
| e |
1.00014284 |
| q (au) |
1.247719 |
| a (au) |
-8734.775296 |
| i (deg) |
117.526989 |
| Ω (om, deg) |
223.231185 |
| ω (w, deg) |
263.592510 |
| M (ma, deg) |
-0.000250 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.173 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.173 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.684 |
| 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 |
| 2021-10-02 |
2021-12-19 |
-4.4532 |
+2.177 |
| 2021-12-19 |
2022-02-25 |
-13.3606 |
+5.458 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
13:49:21.41 |
+32:17:54.3 |
HIP 67504 |
15.55 |
| 2026-07-29 12:00 |
13:49:22.50 |
+32:16:37.2 |
HIP 67504 |
16.57 |
| 2026-07-30 00:00 |
13:49:23.67 |
+32:15:20.1 |
HIP 67504 |
17.61 |
| 2026-07-30 12:00 |
13:49:24.92 |
+32:14:02.8 |
HIP 67504 |
18.69 |
| 2026-07-31 00:00 |
13:49:26.24 |
+32:12:45.5 |
HIP 67504 |
19.79 |
| 2026-07-31 12:00 |
13:49:27.64 |
+32:11:28.1 |
HIP 67316 |
20.16 |
| 2026-08-01 00:00 |
13:49:29.12 |
+32:10:10.6 |
HIP 67316 |
20.26 |
| 2026-08-01 12:00 |
13:49:30.67 |
+32:08:53.1 |
HIP 67316 |
20.45 |
| 2026-08-02 00:00 |
13:49:32.29 |
+32:07:35.5 |
HIP 67316 |
20.75 |
| 2026-08-02 12:00 |
13:49:33.99 |
+32:06:17.9 |
HIP 67316 |
21.15 |
| 2026-08-03 00:00 |
13:49:35.77 |
+32:05:00.3 |
HIP 67316 |
21.64 |
| 2026-08-03 12:00 |
13:49:37.62 |
+32:03:42.5 |
HIP 67316 |
22.21 |
| 2026-08-04 00:00 |
13:49:39.54 |
+32:02:24.8 |
HIP 67316 |
22.87 |
| 2026-08-04 12:00 |
13:49:41.54 |
+32:01:07.1 |
HIP 67316 |
23.60 |
| 2026-08-05 00:00 |
13:49:43.61 |
+31:59:49.3 |
HIP 67316 |
24.40 |
| 2026-08-05 12:00 |
13:49:45.76 |
+31:58:31.5 |
HIP 67316 |
25.26 |
| 2026-08-06 00:00 |
13:49:47.98 |
+31:57:13.7 |
HIP 67316 |
26.18 |
| 2026-08-06 12:00 |
13:49:50.27 |
+31:55:55.9 |
HIP 67656 |
26.96 |
| 2026-08-07 00:00 |
13:49:52.63 |
+31:54:38.0 |
HIP 67656 |
27.19 |
| 2026-08-07 12:00 |
13:49:55.07 |
+31:53:20.2 |
HIP 67656 |
27.47 |
| 2026-08-08 00:00 |
13:49:57.58 |
+31:52:02.5 |
HIP 67656 |
27.80 |
| 2026-08-08 12:00 |
13:50:00.16 |
+31:50:44.7 |
HIP 67656 |
28.19 |
| 2026-08-09 00:00 |
13:50:02.81 |
+31:49:26.9 |
HIP 67656 |
28.63 |
| 2026-08-09 12:00 |
13:50:05.53 |
+31:48:09.2 |
HIP 67656 |
29.12 |
| 2026-08-10 00:00 |
13:50:08.33 |
+31:46:51.6 |
HIP 67656 |
29.66 |
| 2026-08-10 12:00 |
13:50:11.19 |
+31:45:33.9 |
HIP 67656 |
30.25 |
| 2026-08-11 00:00 |
13:50:14.13 |
+31:44:16.3 |
HIP 67525 |
30.37 |
| 2026-08-11 12:00 |
13:50:17.13 |
+31:42:58.8 |
HIP 67525 |
29.12 |
| 2026-08-12 00:00 |
13:50:20.21 |
+31:41:41.4 |
HIP 67525 |
27.89 |
| 2026-08-12 12:00 |
13:50:23.35 |
+31:40:24.0 |
HIP 67525 |
26.69 |
| 2026-08-13 00:00 |
13:50:26.57 |
+31:39:06.6 |
HIP 67525 |
25.51 |
| 2026-08-13 12:00 |
13:50:29.85 |
+31:37:49.4 |
HIP 67525 |
24.38 |
| 2026-08-14 00:00 |
13:50:33.20 |
+31:36:32.2 |
HIP 67525 |
23.28 |
| 2026-08-14 12:00 |
13:50:36.61 |
+31:35:15.2 |
HIP 67525 |
22.23 |
| 2026-08-15 00:00 |
13:50:40.10 |
+31:33:58.2 |
HIP 67525 |
21.24 |
| 2026-08-15 12:00 |
13:50:43.65 |
+31:32:41.3 |
HIP 67525 |
20.31 |
| 2026-08-16 00:00 |
13:50:47.27 |
+31:31:24.6 |
HIP 67525 |
19.47 |
| 2026-08-16 12:00 |
13:50:50.95 |
+31:30:08.0 |
HIP 67525 |
18.71 |
| 2026-08-17 00:00 |
13:50:54.70 |
+31:28:51.4 |
HIP 67525 |
18.06 |
| 2026-08-17 12:00 |
13:50:58.51 |
+31:27:35.1 |
HIP 67525 |
17.52 |
| 2026-08-18 00:00 |
13:51:02.39 |
+31:26:18.8 |
HIP 67525 |
17.11 |
| 2026-08-18 12:00 |
13:51:06.34 |
+31:25:02.7 |
HIP 67525 |
16.85 |
| 2026-08-19 00:00 |
13:51:10.35 |
+31:23:46.7 |
HIP 67525 |
16.72 |