| Parameter |
Value |
| Designation |
C/2001 A1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2000-09-17T14:53:00.830400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:08Z |
| Obs used |
126 |
| NEO |
- |
| M1 |
12.800 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2001-02-04.0000000 |
| e |
0.99093655 |
| q (au) |
2.406447 |
| a (au) |
265.511207 |
| i (deg) |
59.940739 |
| Ω (om, deg) |
339.594496 |
| ω (w, deg) |
107.889040 |
| M (ma, deg) |
0.031753 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.703 + 3.720\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.703 |
| n |
3.720 |
| gf |
1.000 |
| gb |
-0.555 |
| 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) |
| 2026-09-20 00:00 |
12:31:40.25 |
-71:40:41.1 |
HIP 60763 |
20.55 |
| 2026-09-20 12:00 |
12:31:47.75 |
-71:40:41.7 |
HIP 60763 |
21.14 |
| 2026-09-21 00:00 |
12:31:55.26 |
-71:40:42.6 |
HIP 61034 |
21.67 |
| 2026-09-21 12:00 |
12:32:02.78 |
-71:40:43.8 |
HIP 61034 |
21.83 |
| 2026-09-22 00:00 |
12:32:10.30 |
-71:40:45.3 |
HIP 61034 |
22.00 |
| 2026-09-22 12:00 |
12:32:17.84 |
-71:40:47.1 |
HIP 61034 |
22.19 |
| 2026-09-23 00:00 |
12:32:25.39 |
-71:40:49.1 |
HIP 61034 |
22.38 |
| 2026-09-23 12:00 |
12:32:32.95 |
-71:40:51.5 |
HIP 61034 |
22.59 |
| 2026-09-24 00:00 |
12:32:40.51 |
-71:40:54.1 |
HIP 61034 |
22.80 |
| 2026-09-24 12:00 |
12:32:48.08 |
-71:40:57.1 |
HIP 61034 |
23.02 |
| 2026-09-25 00:00 |
12:32:55.66 |
-71:41:00.3 |
HIP 61034 |
23.25 |
| 2026-09-25 12:00 |
12:33:03.25 |
-71:41:03.8 |
HIP 61034 |
23.49 |
| 2026-09-26 00:00 |
12:33:10.84 |
-71:41:07.6 |
HIP 61034 |
23.74 |
| 2026-09-26 12:00 |
12:33:18.44 |
-71:41:11.6 |
HIP 61034 |
24.00 |
| 2026-09-27 00:00 |
12:33:26.05 |
-71:41:16.0 |
HIP 61034 |
24.26 |
| 2026-09-27 12:00 |
12:33:33.66 |
-71:41:20.6 |
HIP 61034 |
24.53 |
| 2026-09-28 00:00 |
12:33:41.27 |
-71:41:25.6 |
HIP 61034 |
24.81 |
| 2026-09-28 12:00 |
12:33:48.89 |
-71:41:30.8 |
HIP 61034 |
25.10 |
| 2026-09-29 00:00 |
12:33:56.52 |
-71:41:36.3 |
HIP 61034 |
25.40 |
| 2026-09-29 12:00 |
12:34:04.15 |
-71:41:42.1 |
HIP 61751 |
25.17 |
| 2026-09-30 00:00 |
12:34:11.78 |
-71:41:48.1 |
HIP 61751 |
24.60 |
| 2026-09-30 12:00 |
12:34:19.42 |
-71:41:54.5 |
HIP 61751 |
24.02 |
| 2026-10-01 00:00 |
12:34:27.06 |
-71:42:01.1 |
HIP 61751 |
23.46 |
| 2026-10-01 12:00 |
12:34:34.70 |
-71:42:08.1 |
HIP 61751 |
22.89 |
| 2026-10-02 00:00 |
12:34:42.34 |
-71:42:15.3 |
HIP 61751 |
22.33 |
| 2026-10-02 12:00 |
12:34:49.99 |
-71:42:22.8 |
HIP 61751 |
21.77 |
| 2026-10-03 00:00 |
12:34:57.63 |
-71:42:30.5 |
HIP 61751 |
21.22 |
| 2026-10-03 12:00 |
12:35:05.28 |
-71:42:38.6 |
HIP 61751 |
20.67 |
| 2026-10-04 00:00 |
12:35:12.92 |
-71:42:47.0 |
HIP 61751 |
20.12 |
| 2026-10-04 12:00 |
12:35:20.57 |
-71:42:55.6 |
HIP 61751 |
19.58 |
| 2026-10-05 00:00 |
12:35:28.22 |
-71:43:04.5 |
HIP 61751 |
19.05 |
| 2026-10-05 12:00 |
12:35:35.86 |
-71:43:13.7 |
HIP 61751 |
18.53 |
| 2026-10-06 00:00 |
12:35:43.50 |
-71:43:23.2 |
HIP 61751 |
18.01 |
| 2026-10-06 12:00 |
12:35:51.15 |
-71:43:32.9 |
HIP 61751 |
17.50 |
| 2026-10-07 00:00 |
12:35:58.78 |
-71:43:43.0 |
HIP 61751 |
17.00 |
| 2026-10-07 12:00 |
12:36:06.42 |
-71:43:53.3 |
HIP 61751 |
16.52 |
| 2026-10-08 00:00 |
12:36:14.05 |
-71:44:03.9 |
HIP 61751 |
16.04 |
| 2026-10-08 12:00 |
12:36:21.68 |
-71:44:14.8 |
HIP 61751 |
15.58 |
| 2026-10-09 00:00 |
12:36:29.30 |
-71:44:26.0 |
HIP 61751 |
15.13 |
| 2026-10-09 12:00 |
12:36:36.92 |
-71:44:37.4 |
HIP 61751 |
14.70 |
| 2026-10-10 00:00 |
12:36:44.54 |
-71:44:49.2 |
HIP 61751 |
14.28 |
| 2026-10-10 12:00 |
12:36:52.14 |
-71:45:01.2 |
HIP 61751 |
13.89 |
| 2026-10-11 00:00 |
12:36:59.75 |
-71:45:13.5 |
HIP 61751 |
13.51 |