| Parameter |
Value |
| Designation |
C/2025 A1 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2027-03-12T15:41:40.225920Z |
| Orbit solution date (soln_date, UTC) |
2026-06-05T03:03:24Z |
| Obs used |
474 |
| NEO |
- |
| M1 |
5.500 |
| K1 |
12.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-01-02T06:39:55.180800Z |
| Discovery magnitude (MPC) |
20.50 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-08-11.0000000 |
| e |
1.00250161 |
| q (au) |
5.345281 |
| a (au) |
-2136.738509 |
| i (deg) |
33.424498 |
| Ω (om, deg) |
101.331078 |
| ω (w, deg) |
68.045960 |
| M (ma, deg) |
-0.005774 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.647 + 5.312\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.647 |
| n |
5.312 |
| gf |
0.920 |
| gb |
-0.976 |
| k |
1.000 |
| δ90 |
7.959 |
| 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) |
| 2026-06-01 00:00 |
08:51:01.96 |
+36:20:26.7 |
HIP 43296 |
24.77 |
| 2026-06-01 12:00 |
08:51:25.29 |
+36:19:12.8 |
HIP 43296 |
29.53 |
| 2026-06-02 00:00 |
08:51:48.73 |
+36:17:58.5 |
HIP 43296 |
34.35 |
| 2026-06-02 12:00 |
08:52:12.28 |
+36:16:44.0 |
HIP 43419 |
38.92 |
| 2026-06-03 00:00 |
08:52:35.95 |
+36:15:29.1 |
HIP 43852 |
40.45 |
| 2026-06-03 12:00 |
08:52:59.74 |
+36:14:13.9 |
HIP 43852 |
35.58 |
| 2026-06-04 00:00 |
08:53:23.63 |
+36:12:58.4 |
HIP 43852 |
30.70 |
| 2026-06-04 12:00 |
08:53:47.64 |
+36:11:42.7 |
HIP 43852 |
25.84 |
| 2026-06-05 00:00 |
08:54:11.75 |
+36:10:26.6 |
HIP 43852 |
21.02 |
| 2026-06-05 12:00 |
08:54:35.98 |
+36:09:10.2 |
HIP 43852 |
16.30 |
| 2026-06-06 00:00 |
08:55:00.31 |
+36:07:53.5 |
HIP 43852 |
11.83 |
| 2026-06-06 12:00 |
08:55:24.76 |
+36:06:36.5 |
HIP 43852 |
8.11 |
| 2026-06-07 00:00 |
08:55:49.31 |
+36:05:19.2 |
HIP 43852 |
6.58 |
| 2026-06-07 12:00 |
08:56:13.97 |
+36:04:01.6 |
HIP 43852 |
8.58 |
| 2026-06-08 00:00 |
08:56:38.73 |
+36:02:43.7 |
HIP 43852 |
12.54 |
| 2026-06-08 12:00 |
08:57:03.60 |
+36:01:25.5 |
HIP 43852 |
17.18 |
| 2026-06-09 00:00 |
08:57:28.57 |
+36:00:07.1 |
HIP 44064 |
16.88 |
| 2026-06-09 12:00 |
08:57:53.65 |
+35:58:48.3 |
HIP 44064 |
12.65 |
| 2026-06-10 00:00 |
08:58:18.83 |
+35:57:29.3 |
HIP 44064 |
9.49 |
| 2026-06-10 12:00 |
08:58:44.11 |
+35:56:10.0 |
HIP 44064 |
8.69 |
| 2026-06-11 00:00 |
08:59:09.50 |
+35:54:50.4 |
HIP 44064 |
10.84 |
| 2026-06-11 12:00 |
08:59:34.98 |
+35:53:30.5 |
HIP 44064 |
14.71 |
| 2026-06-12 00:00 |
09:00:00.57 |
+35:52:10.4 |
HIP 44064 |
19.31 |
| 2026-06-12 12:00 |
09:00:26.25 |
+35:50:50.0 |
HIP 44335 |
15.66 |
| 2026-06-13 00:00 |
09:00:52.04 |
+35:49:29.3 |
HIP 44335 |
10.63 |
| 2026-06-13 12:00 |
09:01:17.92 |
+35:48:08.4 |
HIP 44335 |
6.21 |
| 2026-06-14 00:00 |
09:01:43.89 |
+35:46:47.2 |
HIP 44335 |
4.78 |
| 2026-06-14 12:00 |
09:02:09.97 |
+35:45:25.8 |
HIP 44335 |
8.16 |
| 2026-06-15 00:00 |
09:02:36.14 |
+35:44:04.1 |
HIP 44347 |
12.72 |
| 2026-06-15 12:00 |
09:03:02.40 |
+35:42:42.1 |
HIP 44347 |
17.53 |
| 2026-06-16 00:00 |
09:03:28.75 |
+35:41:19.9 |
HIP 44388 |
22.50 |
| 2026-06-16 12:00 |
09:03:55.20 |
+35:39:57.5 |
HIP 44388 |
24.70 |
| 2026-06-17 00:00 |
09:04:21.74 |
+35:38:34.8 |
HIP 44388 |
27.87 |
| 2026-06-17 12:00 |
09:04:48.37 |
+35:37:11.9 |
HIP 44720 |
29.31 |
| 2026-06-18 00:00 |
09:05:15.09 |
+35:35:48.7 |
HIP 44720 |
24.20 |
| 2026-06-18 12:00 |
09:05:41.90 |
+35:34:25.3 |
HIP 44720 |
19.36 |
| 2026-06-19 00:00 |
09:06:08.79 |
+35:33:01.7 |
HIP 44720 |
15.06 |
| 2026-06-19 12:00 |
09:06:35.77 |
+35:31:37.9 |
HIP 44720 |
11.94 |
| 2026-06-20 00:00 |
09:07:02.84 |
+35:30:13.8 |
HIP 44720 |
11.09 |
| 2026-06-20 12:00 |
09:07:29.99 |
+35:28:49.5 |
HIP 44720 |
12.97 |
| 2026-06-21 00:00 |
09:07:57.23 |
+35:27:25.0 |
HIP 44882 |
10.76 |
| 2026-06-21 12:00 |
09:08:24.55 |
+35:26:00.3 |
HIP 44882 |
5.57 |
| 2026-06-22 00:00 |
09:08:51.95 |
+35:24:35.4 |
HIP 44882 |
3.49 |