| Parameter |
Value |
| Designation |
C/2015 A1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-03-13T01:22:02.553600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:05Z |
| Obs used |
60 |
| NEO |
- |
| M1 |
7.300 |
| K1 |
32.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-03-29.0000000 |
| e |
0.90081449 |
| q (au) |
1.995505 |
| a (au) |
20.118914 |
| i (deg) |
80.365746 |
| Ω (om, deg) |
341.085968 |
| ω (w, deg) |
244.879299 |
| M (ma, deg) |
0.174128 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.204 + 4.454\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.204 |
| n |
4.454 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-03-26 00:00 |
22:16:59.43 |
+31:48:49.6 |
HIP 110080 |
22.34 |
| 2026-03-26 12:00 |
22:17:04.16 |
+31:49:42.6 |
HIP 110080 |
22.64 |
| 2026-03-27 00:00 |
22:17:08.86 |
+31:50:35.8 |
HIP 110080 |
23.03 |
| 2026-03-27 12:00 |
22:17:13.54 |
+31:51:29.3 |
HIP 110080 |
23.50 |
| 2026-03-28 00:00 |
22:17:18.19 |
+31:52:23.1 |
HIP 110080 |
24.04 |
| 2026-03-28 12:00 |
22:17:22.82 |
+31:53:17.1 |
HIP 110080 |
24.64 |
| 2026-03-29 00:00 |
22:17:27.42 |
+31:54:11.4 |
HIP 110080 |
25.31 |
| 2026-03-29 12:00 |
22:17:31.99 |
+31:55:06.0 |
HIP 110080 |
26.03 |
| 2026-03-30 00:00 |
22:17:36.53 |
+31:56:00.8 |
HIP 110080 |
26.80 |
| 2026-03-30 12:00 |
22:17:41.05 |
+31:56:55.9 |
HIP 110080 |
27.62 |
| 2026-03-31 00:00 |
22:17:45.54 |
+31:57:51.2 |
HIP 110080 |
28.48 |
| 2026-03-31 12:00 |
22:17:50.00 |
+31:58:46.7 |
HIP 110080 |
29.39 |
| 2026-04-01 00:00 |
22:17:54.43 |
+31:59:42.5 |
HIP 110080 |
30.32 |
| 2026-04-01 12:00 |
22:17:58.83 |
+32:00:38.6 |
HIP 110080 |
31.29 |
| 2026-04-02 00:00 |
22:18:03.20 |
+32:01:34.8 |
HIP 110080 |
32.29 |
| 2026-04-02 12:00 |
22:18:07.54 |
+32:02:31.4 |
HIP 110080 |
33.31 |
| 2026-04-03 00:00 |
22:18:11.85 |
+32:03:28.1 |
HIP 110080 |
34.36 |
| 2026-04-03 12:00 |
22:18:16.14 |
+32:04:25.1 |
HIP 110080 |
35.42 |
| 2026-04-04 00:00 |
22:18:20.39 |
+32:05:22.3 |
HIP 110080 |
36.51 |
| 2026-04-04 12:00 |
22:18:24.61 |
+32:06:19.7 |
HIP 110080 |
37.61 |
| 2026-04-05 00:00 |
22:18:28.80 |
+32:07:17.3 |
HIP 110080 |
38.73 |
| 2026-04-05 12:00 |
22:18:32.96 |
+32:08:15.1 |
HIP 109979 |
38.90 |
| 2026-04-06 00:00 |
22:18:37.09 |
+32:09:13.2 |
HIP 109979 |
38.77 |
| 2026-04-06 12:00 |
22:18:41.18 |
+32:10:11.5 |
HIP 109979 |
38.69 |
| 2026-04-07 00:00 |
22:18:45.25 |
+32:11:10.0 |
HIP 109979 |
38.64 |
| 2026-04-07 12:00 |
22:18:49.28 |
+32:12:08.7 |
HIP 109979 |
38.62 |
| 2026-04-08 00:00 |
22:18:53.28 |
+32:13:07.5 |
HIP 109979 |
38.64 |
| 2026-04-08 12:00 |
22:18:57.24 |
+32:14:06.6 |
HIP 109979 |
38.70 |
| 2026-04-09 00:00 |
22:19:01.17 |
+32:15:05.9 |
HIP 110267 |
38.33 |
| 2026-04-09 12:00 |
22:19:05.07 |
+32:16:05.4 |
HIP 110267 |
37.11 |
| 2026-04-10 00:00 |
22:19:08.94 |
+32:17:05.0 |
HIP 110267 |
35.90 |
| 2026-04-10 12:00 |
22:19:12.77 |
+32:18:04.9 |
HIP 110267 |
34.68 |
| 2026-04-11 00:00 |
22:19:16.56 |
+32:19:04.9 |
HIP 110267 |
33.48 |
| 2026-04-11 12:00 |
22:19:20.32 |
+32:20:05.1 |
HIP 110267 |
32.28 |
| 2026-04-12 00:00 |
22:19:24.05 |
+32:21:05.5 |
HIP 110267 |
31.08 |
| 2026-04-12 12:00 |
22:19:27.74 |
+32:22:06.1 |
HIP 110267 |
29.89 |
| 2026-04-13 00:00 |
22:19:31.40 |
+32:23:06.8 |
HIP 110267 |
28.71 |
| 2026-04-13 12:00 |
22:19:35.02 |
+32:24:07.7 |
HIP 110267 |
27.53 |
| 2026-04-14 00:00 |
22:19:38.60 |
+32:25:08.7 |
HIP 110267 |
26.36 |
| 2026-04-14 12:00 |
22:19:42.15 |
+32:26:10.0 |
HIP 110267 |
25.21 |
| 2026-04-15 00:00 |
22:19:45.66 |
+32:27:11.3 |
HIP 110267 |
24.06 |
| 2026-04-15 12:00 |
22:19:49.13 |
+32:28:12.8 |
HIP 110267 |
22.92 |
| 2026-04-16 00:00 |
22:19:52.57 |
+32:29:14.5 |
HIP 110267 |
21.79 |