| Parameter |
Value |
| Designation |
221P/LINEAR |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-01-24T08:32:46.219200Z |
| Orbit solution date (soln_date, UTC) |
2022-10-28T22:13:13Z |
| Obs used |
627 |
| NEO |
- |
| M1 |
14.000 |
| K1 |
13.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-08-08.0000000 |
| e |
0.48757555 |
| q (au) |
1.779766 |
| a (au) |
3.473226 |
| i (deg) |
11.431021 |
| Ω (om, deg) |
229.989314 |
| ω (w, deg) |
39.511181 |
| M (ma, deg) |
140.944591 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.562 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.562 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.891 |
| k |
0.999 |
| δ90 |
9.995 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
07:04:04.16 |
+13:36:24.1 |
HIP 34210 |
22.97 |
| 2026-05-12 12:00 |
07:04:25.25 |
+13:36:26.5 |
HIP 34210 |
18.08 |
| 2026-05-13 00:00 |
07:04:46.45 |
+13:36:28.2 |
HIP 34210 |
13.34 |
| 2026-05-13 12:00 |
07:05:07.77 |
+13:36:29.3 |
HIP 34210 |
9.04 |
| 2026-05-14 00:00 |
07:05:29.21 |
+13:36:29.7 |
HIP 34210 |
6.26 |
| 2026-05-14 12:00 |
07:05:50.76 |
+13:36:29.5 |
HIP 34210 |
7.17 |
| 2026-05-15 00:00 |
07:06:12.43 |
+13:36:28.6 |
HIP 34210 |
10.91 |
| 2026-05-15 12:00 |
07:06:34.22 |
+13:36:27.1 |
HIP 34328 |
13.53 |
| 2026-05-16 00:00 |
07:06:56.11 |
+13:36:25.0 |
HIP 34328 |
12.25 |
| 2026-05-16 12:00 |
07:07:18.12 |
+13:36:22.1 |
HIP 34328 |
13.18 |
| 2026-05-17 00:00 |
07:07:40.24 |
+13:36:18.6 |
HIP 34328 |
15.97 |
| 2026-05-17 12:00 |
07:08:02.47 |
+13:36:14.5 |
HIP 34328 |
19.86 |
| 2026-05-18 00:00 |
07:08:24.81 |
+13:36:09.7 |
HIP 34557 |
16.54 |
| 2026-05-18 12:00 |
07:08:47.26 |
+13:36:04.2 |
HIP 34557 |
11.25 |
| 2026-05-19 00:00 |
07:09:09.82 |
+13:35:58.0 |
HIP 34557 |
6.23 |
| 2026-05-19 12:00 |
07:09:32.48 |
+13:35:51.2 |
HIP 34557 |
3.37 |
| 2026-05-20 00:00 |
07:09:55.24 |
+13:35:43.8 |
HIP 34557 |
6.70 |
| 2026-05-20 12:00 |
07:10:18.11 |
+13:35:35.6 |
HIP 34557 |
11.85 |
| 2026-05-21 00:00 |
07:10:41.08 |
+13:35:26.8 |
HIP 34557 |
17.28 |
| 2026-05-21 12:00 |
07:11:04.15 |
+13:35:17.3 |
HIP 34557 |
22.81 |
| 2026-05-22 00:00 |
07:11:27.33 |
+13:35:07.2 |
HIP 34557 |
28.39 |
| 2026-05-22 12:00 |
07:11:50.60 |
+13:34:56.4 |
HIP 34913 |
25.09 |
| 2026-05-23 00:00 |
07:12:13.97 |
+13:34:44.9 |
HIP 34913 |
20.23 |
| 2026-05-23 12:00 |
07:12:37.44 |
+13:34:32.7 |
HIP 34913 |
15.90 |
| 2026-05-24 00:00 |
07:13:01.00 |
+13:34:19.9 |
HIP 34913 |
12.71 |
| 2026-05-24 12:00 |
07:13:24.66 |
+13:34:06.4 |
HIP 34913 |
11.67 |
| 2026-05-25 00:00 |
07:13:48.42 |
+13:33:52.2 |
HIP 34913 |
13.33 |
| 2026-05-25 12:00 |
07:14:12.26 |
+13:33:37.4 |
HIP 34913 |
16.93 |
| 2026-05-26 00:00 |
07:14:36.21 |
+13:33:21.9 |
HIP 34913 |
21.54 |
| 2026-05-26 12:00 |
07:15:00.24 |
+13:33:05.7 |
HIP 35124 |
21.31 |
| 2026-05-27 00:00 |
07:15:24.36 |
+13:32:48.8 |
HIP 35124 |
19.51 |
| 2026-05-27 12:00 |
07:15:48.57 |
+13:32:31.3 |
HIP 35124 |
19.41 |
| 2026-05-28 00:00 |
07:16:12.88 |
+13:32:13.0 |
HIP 35124 |
21.05 |
| 2026-05-28 12:00 |
07:16:37.27 |
+13:31:54.1 |
HIP 35268 |
21.69 |
| 2026-05-29 00:00 |
07:17:01.75 |
+13:31:34.6 |
HIP 35268 |
20.50 |
| 2026-05-29 12:00 |
07:17:26.31 |
+13:31:14.3 |
HIP 35268 |
21.02 |
| 2026-05-30 00:00 |
07:17:50.96 |
+13:30:53.4 |
HIP 35268 |
23.14 |
| 2026-05-30 12:00 |
07:18:15.70 |
+13:30:31.8 |
HIP 35268 |
26.50 |
| 2026-05-31 00:00 |
07:18:40.52 |
+13:30:09.5 |
HIP 35501 |
29.83 |
| 2026-05-31 12:00 |
07:19:05.42 |
+13:29:46.5 |
HIP 35501 |
27.94 |
| 2026-06-01 00:00 |
07:19:30.41 |
+13:29:22.9 |
HIP 35501 |
27.30 |
| 2026-06-01 12:00 |
07:19:55.47 |
+13:28:58.6 |
HIP 35501 |
28.01 |
| 2026-06-02 00:00 |
07:20:20.62 |
+13:28:33.5 |
HIP 35646 |
23.76 |