C/2015 H1 (Bressi)
| Parameter |
Value |
| Designation |
C/2015 H1 (Bressi) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-03-28T14:52:26.330880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:09Z |
| Obs used |
210 |
| NEO |
- |
| M1 |
4.200 |
| K1 |
40.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-05-27.0000000 |
| e |
0.94079404 |
| q (au) |
1.926359 |
| a (au) |
32.536572 |
| i (deg) |
140.655574 |
| Ω (om, deg) |
325.804456 |
| ω (w, deg) |
21.756727 |
| M (ma, deg) |
0.315347 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.248 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.248 |
| n |
6.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2015-04-20 |
2015-07-27 |
+16.3060 |
-4.976 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
10:14:21.36 |
+14:22:17.1 |
HIP 50124 |
30.54 |
| 2026-02-03 12:00 |
10:14:15.99 |
+14:22:43.8 |
HIP 50124 |
30.75 |
| 2026-02-04 00:00 |
10:14:10.60 |
+14:23:10.5 |
HIP 50124 |
31.02 |
| 2026-02-04 12:00 |
10:14:05.20 |
+14:23:37.2 |
HIP 50124 |
31.35 |
| 2026-02-05 00:00 |
10:13:59.79 |
+14:24:04.0 |
HIP 50124 |
31.74 |
| 2026-02-05 12:00 |
10:13:54.37 |
+14:24:30.7 |
HIP 50124 |
32.18 |
| 2026-02-06 00:00 |
10:13:48.93 |
+14:24:57.5 |
HIP 50124 |
32.68 |
| 2026-02-06 12:00 |
10:13:43.48 |
+14:25:24.3 |
HIP 50124 |
33.23 |
| 2026-02-07 00:00 |
10:13:38.02 |
+14:25:51.1 |
HIP 50124 |
33.83 |
| 2026-02-07 12:00 |
10:13:32.55 |
+14:26:18.0 |
HIP 49965 |
34.11 |
| 2026-02-08 00:00 |
10:13:27.07 |
+14:26:44.8 |
HIP 49965 |
32.93 |
| 2026-02-08 12:00 |
10:13:21.58 |
+14:27:11.7 |
HIP 49965 |
31.76 |
| 2026-02-09 00:00 |
10:13:16.08 |
+14:27:38.5 |
HIP 49965 |
30.62 |
| 2026-02-09 12:00 |
10:13:10.57 |
+14:28:05.3 |
HIP 49965 |
29.49 |
| 2026-02-10 00:00 |
10:13:05.05 |
+14:28:32.2 |
HIP 49965 |
28.39 |
| 2026-02-10 12:00 |
10:12:59.52 |
+14:28:59.0 |
HIP 49965 |
27.32 |
| 2026-02-11 00:00 |
10:12:53.98 |
+14:29:25.9 |
HIP 49965 |
26.28 |
| 2026-02-11 12:00 |
10:12:48.44 |
+14:29:52.7 |
HIP 49965 |
25.27 |
| 2026-02-12 00:00 |
10:12:42.89 |
+14:30:19.5 |
HIP 49965 |
24.31 |
| 2026-02-12 12:00 |
10:12:37.33 |
+14:30:46.3 |
HIP 49965 |
23.39 |
| 2026-02-13 00:00 |
10:12:31.76 |
+14:31:13.1 |
HIP 49965 |
22.52 |
| 2026-02-13 12:00 |
10:12:26.19 |
+14:31:39.9 |
HIP 49965 |
21.71 |
| 2026-02-14 00:00 |
10:12:20.62 |
+14:32:06.6 |
HIP 49866 |
20.60 |
| 2026-02-14 12:00 |
10:12:15.04 |
+14:32:33.3 |
HIP 49866 |
19.34 |
| 2026-02-15 00:00 |
10:12:09.45 |
+14:33:00.0 |
HIP 49866 |
18.11 |
| 2026-02-15 12:00 |
10:12:03.87 |
+14:33:26.7 |
HIP 49866 |
16.90 |
| 2026-02-16 00:00 |
10:11:58.27 |
+14:33:53.3 |
HIP 49866 |
15.74 |
| 2026-02-16 12:00 |
10:11:52.68 |
+14:34:19.9 |
HIP 49866 |
14.61 |
| 2026-02-17 00:00 |
10:11:47.08 |
+14:34:46.4 |
HIP 49866 |
13.54 |
| 2026-02-17 12:00 |
10:11:41.48 |
+14:35:12.9 |
HIP 49866 |
12.55 |
| 2026-02-18 00:00 |
10:11:35.88 |
+14:35:39.4 |
HIP 49866 |
11.64 |
| 2026-02-18 12:00 |
10:11:30.28 |
+14:36:05.8 |
HIP 49866 |
10.84 |
| 2026-02-19 00:00 |
10:11:24.68 |
+14:36:32.2 |
HIP 49866 |
10.18 |
| 2026-02-19 12:00 |
10:11:19.08 |
+14:36:58.5 |
HIP 49866 |
9.69 |
| 2026-02-20 00:00 |
10:11:13.48 |
+14:37:24.8 |
HIP 49866 |
9.38 |
| 2026-02-20 12:00 |
10:11:07.87 |
+14:37:51.0 |
HIP 49866 |
9.29 |
| 2026-02-21 00:00 |
10:11:02.28 |
+14:38:17.1 |
HIP 49866 |
9.41 |
| 2026-02-21 12:00 |
10:10:56.68 |
+14:38:43.2 |
HIP 49866 |
9.74 |
| 2026-02-22 00:00 |
10:10:51.08 |
+14:39:09.2 |
HIP 49866 |
10.26 |
| 2026-02-22 12:00 |
10:10:45.49 |
+14:39:35.2 |
HIP 49866 |
10.94 |
| 2026-02-23 00:00 |
10:10:39.90 |
+14:40:01.1 |
HIP 49866 |
11.75 |
| 2026-02-23 12:00 |
10:10:34.32 |
+14:40:26.9 |
HIP 49866 |
12.67 |
| 2026-02-24 00:00 |
10:10:28.74 |
+14:40:52.6 |
HIP 49866 |
13.67 |