C/2025 K2 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2025 K2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-10-25T07:48:17.305920Z |
| Orbit solution date (soln_date, UTC) |
2025-08-12T09:42:16Z |
| Obs used |
26 |
| NEO |
- |
| M1 |
7.400 |
| K1 |
21.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-05-29T12:48:33.840000Z |
| Discovery magnitude (MPC) |
20.47 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-06-09.0000000 |
| e |
0.88709889 |
| q (au) |
2.863643 |
| a (au) |
25.364173 |
| i (deg) |
113.978010 |
| Ω (om, deg) |
113.828014 |
| ω (w, deg) |
232.466816 |
| M (ma, deg) |
358.932730 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.125 + 4.640\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.125 |
| n |
4.640 |
| gf |
1.000 |
| gb |
-0.976 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
16:28:27.02 |
-80:41:10.3 |
HIP 80200 |
15.14 |
| 2026-02-03 12:00 |
16:27:37.85 |
-80:52:58.6 |
HIP 80200 |
15.05 |
| 2026-02-04 00:00 |
16:26:44.57 |
-81:04:49.7 |
HIP 80507 |
5.05 |
| 2026-02-04 12:00 |
16:25:46.88 |
-81:16:43.3 |
HIP 80507 |
7.11 |
| 2026-02-05 00:00 |
16:24:44.43 |
-81:28:39.3 |
HIP 80507 |
19.25 |
| 2026-02-05 12:00 |
16:23:36.86 |
-81:40:37.7 |
HIP 80624 |
19.22 |
| 2026-02-06 00:00 |
16:22:23.76 |
-81:52:38.4 |
HIP 80624 |
12.41 |
| 2026-02-06 12:00 |
16:21:04.68 |
-82:04:41.0 |
HIP 79680 |
14.58 |
| 2026-02-07 00:00 |
16:19:39.10 |
-82:16:45.5 |
HIP 80567 |
22.26 |
| 2026-02-07 12:00 |
16:18:06.48 |
-82:28:51.7 |
HIP 80567 |
18.02 |
| 2026-02-08 00:00 |
16:16:26.19 |
-82:40:59.4 |
HIP 80567 |
21.67 |
| 2026-02-08 12:00 |
16:14:37.54 |
-82:53:08.3 |
HIP 80754 |
27.25 |
| 2026-02-09 00:00 |
16:12:39.77 |
-83:05:18.0 |
HIP 80754 |
32.82 |
| 2026-02-09 12:00 |
16:10:32.01 |
-83:17:28.4 |
HIP 78783 |
30.60 |
| 2026-02-10 00:00 |
16:08:13.28 |
-83:29:39.1 |
HIP 78783 |
17.78 |
| 2026-02-10 12:00 |
16:05:42.50 |
-83:41:49.5 |
HIP 78783 |
4.93 |
| 2026-02-11 00:00 |
16:02:58.44 |
-83:53:59.4 |
HIP 78783 |
8.07 |
| 2026-02-11 12:00 |
15:59:59.70 |
-84:06:08.1 |
HIP 79242 |
17.50 |
| 2026-02-12 00:00 |
15:56:44.71 |
-84:18:15.0 |
HIP 79242 |
20.74 |
| 2026-02-12 12:00 |
15:53:11.69 |
-84:30:19.4 |
HIP 76996 |
14.51 |
| 2026-02-13 00:00 |
15:49:18.60 |
-84:42:20.6 |
HIP 76800 |
12.04 |
| 2026-02-13 12:00 |
15:45:03.13 |
-84:54:17.5 |
HIP 76800 |
10.51 |
| 2026-02-14 00:00 |
15:40:22.65 |
-85:06:09.2 |
HIP 76800 |
20.72 |
| 2026-02-14 12:00 |
15:35:14.16 |
-85:17:54.3 |
HIP 75015 |
29.27 |
| 2026-02-15 00:00 |
15:29:34.25 |
-85:29:31.3 |
HIP 75015 |
15.99 |
| 2026-02-15 12:00 |
15:23:19.04 |
-85:40:58.4 |
HIP 75015 |
4.05 |
| 2026-02-16 00:00 |
15:16:24.15 |
-85:52:13.8 |
HIP 75015 |
12.03 |
| 2026-02-16 12:00 |
15:08:44.64 |
-86:03:14.8 |
HIP 73791 |
25.32 |
| 2026-02-17 00:00 |
15:00:15.04 |
-86:13:58.8 |
HIP 72636 |
13.15 |
| 2026-02-17 12:00 |
14:50:49.32 |
-86:24:22.3 |
HIP 72636 |
0.72 |
| 2026-02-18 00:00 |
14:40:21.03 |
-86:34:21.3 |
HIP 72636 |
14.51 |
| 2026-02-18 12:00 |
14:28:43.51 |
-86:43:51.4 |
HIP 72636 |
28.43 |
| 2026-02-19 00:00 |
14:15:50.19 |
-86:52:47.1 |
HIP 66710 |
30.99 |
| 2026-02-19 12:00 |
14:01:35.20 |
-87:01:02.4 |
HIP 66710 |
24.62 |
| 2026-02-20 00:00 |
13:45:54.20 |
-87:08:30.5 |
HIP 66710 |
25.38 |
| 2026-02-20 12:00 |
13:28:45.43 |
-87:15:03.8 |
HIP 64109 |
14.89 |
| 2026-02-21 00:00 |
13:10:10.98 |
-87:20:34.6 |
HIP 64109 |
7.52 |
| 2026-02-21 12:00 |
12:50:18.03 |
-87:24:55.1 |
HIP 64109 |
17.27 |
| 2026-02-22 00:00 |
12:29:19.71 |
-87:27:58.1 |
HIP 58185 |
22.67 |
| 2026-02-22 12:00 |
12:07:35.07 |
-87:29:38.0 |
HIP 58185 |
9.46 |
| 2026-02-23 00:00 |
11:45:27.96 |
-87:29:50.7 |
HIP 58185 |
9.02 |
| 2026-02-23 12:00 |
11:23:24.75 |
-87:28:34.8 |
HIP 56557 |
15.03 |
| 2026-02-24 00:00 |
11:01:51.36 |
-87:25:51.5 |
HIP 56557 |
25.39 |