| 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 |
-0.502 |
| 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
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) |
| 2026-07-29 00:00 |
20:01:35.90 |
+40:42:02.6 |
HIP 98620 |
9.93 |
| 2026-07-29 12:00 |
20:01:28.87 |
+40:41:50.8 |
HIP 98620 |
10.58 |
| 2026-07-30 00:00 |
20:01:21.84 |
+40:41:38.4 |
HIP 98620 |
11.37 |
| 2026-07-30 12:00 |
20:01:14.82 |
+40:41:25.4 |
HIP 98620 |
12.25 |
| 2026-07-31 00:00 |
20:01:07.81 |
+40:41:11.9 |
HIP 98620 |
13.23 |
| 2026-07-31 12:00 |
20:01:00.82 |
+40:40:57.9 |
HIP 98620 |
14.26 |
| 2026-08-01 00:00 |
20:00:53.83 |
+40:40:43.2 |
HIP 98620 |
15.36 |
| 2026-08-01 12:00 |
20:00:46.85 |
+40:40:28.0 |
HIP 98620 |
16.49 |
| 2026-08-02 00:00 |
20:00:39.89 |
+40:40:12.2 |
HIP 98620 |
17.66 |
| 2026-08-02 12:00 |
20:00:32.94 |
+40:39:55.9 |
HIP 98620 |
18.85 |
| 2026-08-03 00:00 |
20:00:26.00 |
+40:39:39.0 |
HIP 98620 |
20.07 |
| 2026-08-03 12:00 |
20:00:19.08 |
+40:39:21.5 |
HIP 98620 |
21.31 |
| 2026-08-04 00:00 |
20:00:12.17 |
+40:39:03.5 |
HIP 98620 |
22.56 |
| 2026-08-04 12:00 |
20:00:05.28 |
+40:38:44.9 |
HIP 98620 |
23.82 |
| 2026-08-05 00:00 |
19:59:58.40 |
+40:38:25.8 |
HIP 98620 |
25.10 |
| 2026-08-05 12:00 |
19:59:51.53 |
+40:38:06.1 |
HIP 98620 |
26.38 |
| 2026-08-06 00:00 |
19:59:44.69 |
+40:37:45.9 |
HIP 98269 |
26.33 |
| 2026-08-06 12:00 |
19:59:37.85 |
+40:37:25.1 |
HIP 98269 |
25.64 |
| 2026-08-07 00:00 |
19:59:31.04 |
+40:37:03.8 |
HIP 98269 |
25.01 |
| 2026-08-07 12:00 |
19:59:24.24 |
+40:36:41.9 |
HIP 98269 |
24.45 |
| 2026-08-08 00:00 |
19:59:17.47 |
+40:36:19.5 |
HIP 98269 |
23.96 |
| 2026-08-08 12:00 |
19:59:10.71 |
+40:35:56.5 |
HIP 98269 |
23.54 |
| 2026-08-09 00:00 |
19:59:03.97 |
+40:35:33.0 |
HIP 98269 |
23.20 |
| 2026-08-09 12:00 |
19:58:57.25 |
+40:35:09.0 |
HIP 98269 |
22.95 |
| 2026-08-10 00:00 |
19:58:50.55 |
+40:34:44.4 |
HIP 98194 |
22.33 |
| 2026-08-10 12:00 |
19:58:43.87 |
+40:34:19.3 |
HIP 98194 |
21.05 |
| 2026-08-11 00:00 |
19:58:37.22 |
+40:33:53.6 |
HIP 98194 |
19.78 |
| 2026-08-11 12:00 |
19:58:30.58 |
+40:33:27.5 |
HIP 98194 |
18.51 |
| 2026-08-12 00:00 |
19:58:23.97 |
+40:33:00.8 |
HIP 98194 |
17.25 |
| 2026-08-12 12:00 |
19:58:17.38 |
+40:32:33.5 |
HIP 98194 |
16.00 |
| 2026-08-13 00:00 |
19:58:10.82 |
+40:32:05.8 |
HIP 98194 |
14.76 |
| 2026-08-13 12:00 |
19:58:04.28 |
+40:31:37.5 |
HIP 98194 |
13.54 |
| 2026-08-14 00:00 |
19:57:57.76 |
+40:31:08.8 |
HIP 98194 |
12.33 |
| 2026-08-14 12:00 |
19:57:51.27 |
+40:30:39.5 |
HIP 98194 |
11.15 |
| 2026-08-15 00:00 |
19:57:44.81 |
+40:30:09.7 |
HIP 98194 |
10.01 |
| 2026-08-15 12:00 |
19:57:38.37 |
+40:29:39.4 |
HIP 98194 |
8.91 |
| 2026-08-16 00:00 |
19:57:31.96 |
+40:29:08.6 |
HIP 98194 |
7.87 |
| 2026-08-16 12:00 |
19:57:25.57 |
+40:28:37.3 |
HIP 98194 |
6.92 |
| 2026-08-17 00:00 |
19:57:19.22 |
+40:28:05.5 |
HIP 98194 |
6.11 |
| 2026-08-17 12:00 |
19:57:12.89 |
+40:27:33.2 |
HIP 98194 |
5.49 |
| 2026-08-18 00:00 |
19:57:06.59 |
+40:27:00.4 |
HIP 98194 |
5.13 |
| 2026-08-18 12:00 |
19:57:00.32 |
+40:26:27.2 |
HIP 98194 |
5.09 |
| 2026-08-19 00:00 |
19:56:54.08 |
+40:25:53.4 |
HIP 98194 |
5.37 |