| Parameter |
Value |
| Designation |
C/2016 B1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-12-04T17:12:22.285440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:22Z |
| Obs used |
522 |
| NEO |
- |
| M1 |
10.500 |
| K1 |
8.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-03-28.0000000 |
| e |
0.99239477 |
| q (au) |
3.206199 |
| a (au) |
421.578150 |
| i (deg) |
50.476159 |
| Ω (om, deg) |
231.954169 |
| ω (w, deg) |
8.559465 |
| M (ma, deg) |
0.012899 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.995 + 3.769\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.995 |
| n |
3.769 |
| gf |
1.000 |
| gb |
-0.508 |
| 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) |
| 2026-05-12 00:00 |
01:03:24.44 |
+34:39:49.8 |
HIP 4840 |
18.73 |
| 2026-05-12 12:00 |
01:03:29.85 |
+34:40:28.2 |
HIP 4840 |
19.99 |
| 2026-05-13 00:00 |
01:03:35.24 |
+34:41:06.7 |
HIP 4840 |
21.25 |
| 2026-05-13 12:00 |
01:03:40.61 |
+34:41:45.3 |
HIP 4840 |
22.51 |
| 2026-05-14 00:00 |
01:03:45.95 |
+34:42:24.0 |
HIP 4840 |
23.77 |
| 2026-05-14 12:00 |
01:03:51.26 |
+34:43:02.9 |
HIP 4840 |
25.02 |
| 2026-05-15 00:00 |
01:03:56.55 |
+34:43:41.8 |
HIP 4988 |
25.79 |
| 2026-05-15 12:00 |
01:04:01.81 |
+34:44:20.9 |
HIP 4988 |
25.16 |
| 2026-05-16 00:00 |
01:04:07.04 |
+34:45:00.1 |
HIP 4988 |
24.58 |
| 2026-05-16 12:00 |
01:04:12.24 |
+34:45:39.3 |
HIP 4988 |
24.04 |
| 2026-05-17 00:00 |
01:04:17.42 |
+34:46:18.7 |
HIP 4988 |
23.56 |
| 2026-05-17 12:00 |
01:04:22.56 |
+34:46:58.1 |
HIP 4988 |
23.14 |
| 2026-05-18 00:00 |
01:04:27.68 |
+34:47:37.7 |
HIP 4988 |
22.77 |
| 2026-05-18 12:00 |
01:04:32.77 |
+34:48:17.3 |
HIP 4988 |
22.46 |
| 2026-05-19 00:00 |
01:04:37.83 |
+34:48:57.0 |
HIP 4988 |
22.21 |
| 2026-05-19 12:00 |
01:04:42.86 |
+34:49:36.8 |
HIP 4988 |
22.02 |
| 2026-05-20 00:00 |
01:04:47.86 |
+34:50:16.6 |
HIP 4988 |
21.89 |
| 2026-05-20 12:00 |
01:04:52.83 |
+34:50:56.6 |
HIP 4988 |
21.83 |
| 2026-05-21 00:00 |
01:04:57.77 |
+34:51:36.6 |
HIP 4988 |
21.83 |
| 2026-05-21 12:00 |
01:05:02.67 |
+34:52:16.7 |
HIP 4988 |
21.90 |
| 2026-05-22 00:00 |
01:05:07.55 |
+34:52:56.8 |
HIP 4988 |
22.02 |
| 2026-05-22 12:00 |
01:05:12.39 |
+34:53:37.0 |
HIP 4988 |
22.20 |
| 2026-05-23 00:00 |
01:05:17.21 |
+34:54:17.3 |
HIP 4988 |
22.44 |
| 2026-05-23 12:00 |
01:05:21.99 |
+34:54:57.7 |
HIP 5226 |
22.30 |
| 2026-05-24 00:00 |
01:05:26.74 |
+34:55:38.1 |
HIP 5226 |
21.12 |
| 2026-05-24 12:00 |
01:05:31.45 |
+34:56:18.5 |
HIP 5226 |
19.94 |
| 2026-05-25 00:00 |
01:05:36.14 |
+34:56:59.0 |
HIP 5226 |
18.77 |
| 2026-05-25 12:00 |
01:05:40.79 |
+34:57:39.6 |
HIP 5226 |
17.61 |
| 2026-05-26 00:00 |
01:05:45.40 |
+34:58:20.2 |
HIP 5226 |
16.45 |
| 2026-05-26 12:00 |
01:05:49.99 |
+34:59:00.8 |
HIP 5226 |
15.29 |
| 2026-05-27 00:00 |
01:05:54.54 |
+34:59:41.5 |
HIP 5226 |
14.14 |
| 2026-05-27 12:00 |
01:05:59.05 |
+35:00:22.2 |
HIP 5226 |
13.00 |
| 2026-05-28 00:00 |
01:06:03.54 |
+35:01:03.0 |
HIP 5226 |
11.86 |
| 2026-05-28 12:00 |
01:06:07.98 |
+35:01:43.8 |
HIP 5226 |
10.72 |
| 2026-05-29 00:00 |
01:06:12.40 |
+35:02:24.6 |
HIP 5226 |
9.59 |
| 2026-05-29 12:00 |
01:06:16.78 |
+35:03:05.5 |
HIP 5226 |
8.47 |
| 2026-05-30 00:00 |
01:06:21.12 |
+35:03:46.4 |
HIP 5226 |
7.36 |
| 2026-05-30 12:00 |
01:06:25.43 |
+35:04:27.3 |
HIP 5226 |
6.25 |
| 2026-05-31 00:00 |
01:06:29.70 |
+35:05:08.2 |
HIP 5226 |
5.14 |
| 2026-05-31 12:00 |
01:06:33.94 |
+35:05:49.2 |
HIP 5226 |
4.05 |
| 2026-06-01 00:00 |
01:06:38.14 |
+35:06:30.2 |
HIP 5226 |
2.96 |
| 2026-06-01 12:00 |
01:06:42.31 |
+35:07:11.2 |
HIP 5226 |
1.90 |
| 2026-06-02 00:00 |
01:06:46.44 |
+35:07:52.2 |
HIP 5226 |
0.91 |