| Parameter |
Value |
| Designation |
C/2015 B2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-05-06T13:45:33.413760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:05Z |
| Obs used |
242 |
| NEO |
- |
| M1 |
11.600 |
| K1 |
7.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-01-19.0000000 |
| e |
1.00023551 |
| q (au) |
3.369608 |
| a (au) |
-14307.501597 |
| i (deg) |
105.088172 |
| Ω (om, deg) |
341.901291 |
| ω (w, deg) |
284.767940 |
| M (ma, deg) |
-0.000063 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.232 + 2.360\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.232 |
| n |
2.360 |
| gf |
1.000 |
| gb |
-0.777 |
| k |
1.000 |
| δ90 |
9.999 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2015-01-06 |
2016-03-11 |
+0.3867 |
-0.622 |
| 2016-06-30 |
2017-09-12 |
+5.7621 |
-2.956 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
20:16:30.09 |
+37:33:38.3 |
HIP 99898 |
4.28 |
| 2026-03-26 12:00 |
20:16:32.37 |
+37:34:45.2 |
HIP 99898 |
4.91 |
| 2026-03-27 00:00 |
20:16:34.60 |
+37:35:52.3 |
HIP 99898 |
5.73 |
| 2026-03-27 12:00 |
20:16:36.79 |
+37:36:59.6 |
HIP 99980 |
5.86 |
| 2026-03-28 00:00 |
20:16:38.92 |
+37:38:07.0 |
HIP 99980 |
4.83 |
| 2026-03-28 12:00 |
20:16:41.01 |
+37:39:14.6 |
HIP 99980 |
3.90 |
| 2026-03-29 00:00 |
20:16:43.05 |
+37:40:22.3 |
HIP 99980 |
3.17 |
| 2026-03-29 12:00 |
20:16:45.05 |
+37:41:30.2 |
HIP 99980 |
2.81 |
| 2026-03-30 00:00 |
20:16:47.00 |
+37:42:38.3 |
HIP 99980 |
2.93 |
| 2026-03-30 12:00 |
20:16:48.89 |
+37:43:46.4 |
HIP 99980 |
3.50 |
| 2026-03-31 00:00 |
20:16:50.74 |
+37:44:54.8 |
HIP 99980 |
4.34 |
| 2026-03-31 12:00 |
20:16:52.54 |
+37:46:03.3 |
HIP 99980 |
5.32 |
| 2026-04-01 00:00 |
20:16:54.30 |
+37:47:11.9 |
HIP 99980 |
6.38 |
| 2026-04-01 12:00 |
20:16:56.00 |
+37:48:20.6 |
HIP 99980 |
7.48 |
| 2026-04-02 00:00 |
20:16:57.66 |
+37:49:29.5 |
HIP 99980 |
8.61 |
| 2026-04-02 12:00 |
20:16:59.26 |
+37:50:38.5 |
HIP 99980 |
9.76 |
| 2026-04-03 00:00 |
20:17:00.82 |
+37:51:47.6 |
HIP 99980 |
10.91 |
| 2026-04-03 12:00 |
20:17:02.32 |
+37:52:56.8 |
HIP 99980 |
12.08 |
| 2026-04-04 00:00 |
20:17:03.78 |
+37:54:06.1 |
HIP 100044 |
11.63 |
| 2026-04-04 12:00 |
20:17:05.19 |
+37:55:15.5 |
HIP 100044 |
10.66 |
| 2026-04-05 00:00 |
20:17:06.54 |
+37:56:25.1 |
HIP 100044 |
9.75 |
| 2026-04-05 12:00 |
20:17:07.85 |
+37:57:34.7 |
HIP 100044 |
8.91 |
| 2026-04-06 00:00 |
20:17:09.11 |
+37:58:44.4 |
HIP 100044 |
8.17 |
| 2026-04-06 12:00 |
20:17:10.31 |
+37:59:54.3 |
HIP 100044 |
7.56 |
| 2026-04-07 00:00 |
20:17:11.47 |
+38:01:04.2 |
HIP 100044 |
7.10 |
| 2026-04-07 12:00 |
20:17:12.57 |
+38:02:14.1 |
HIP 100044 |
6.82 |
| 2026-04-08 00:00 |
20:17:13.62 |
+38:03:24.2 |
HIP 100044 |
6.76 |
| 2026-04-08 12:00 |
20:17:14.63 |
+38:04:34.3 |
HIP 100044 |
6.92 |
| 2026-04-09 00:00 |
20:17:15.57 |
+38:05:44.5 |
HIP 100044 |
7.28 |
| 2026-04-09 12:00 |
20:17:16.47 |
+38:06:54.8 |
HIP 100009 |
7.33 |
| 2026-04-10 00:00 |
20:17:17.32 |
+38:08:05.1 |
HIP 100009 |
6.15 |
| 2026-04-10 12:00 |
20:17:18.11 |
+38:09:15.5 |
HIP 100009 |
4.97 |
| 2026-04-11 00:00 |
20:17:18.86 |
+38:10:25.9 |
HIP 100009 |
3.79 |
| 2026-04-11 12:00 |
20:17:19.55 |
+38:11:36.4 |
HIP 100009 |
2.61 |
| 2026-04-12 00:00 |
20:17:20.18 |
+38:12:46.9 |
HIP 100009 |
1.45 |
| 2026-04-12 12:00 |
20:17:20.77 |
+38:13:57.5 |
HIP 100009 |
0.43 |
| 2026-04-13 00:00 |
20:17:21.30 |
+38:15:08.0 |
HIP 100009 |
1.03 |
| 2026-04-13 12:00 |
20:17:21.78 |
+38:16:18.7 |
HIP 100009 |
2.18 |
| 2026-04-14 00:00 |
20:17:22.21 |
+38:17:29.3 |
HIP 100009 |
3.35 |
| 2026-04-14 12:00 |
20:17:22.58 |
+38:18:39.9 |
HIP 100009 |
4.52 |
| 2026-04-15 00:00 |
20:17:22.90 |
+38:19:50.6 |
HIP 100009 |
5.70 |
| 2026-04-15 12:00 |
20:17:23.17 |
+38:21:01.3 |
HIP 100009 |
6.88 |
| 2026-04-16 00:00 |
20:17:23.38 |
+38:22:11.9 |
HIP 100009 |
8.06 |