| 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) |
| 2026-06-01 00:00 |
10:00:37.70 |
+15:10:23.2 |
HIP 49010 |
20.63 |
| 2026-06-01 12:00 |
10:00:38.32 |
+15:10:12.0 |
HIP 49010 |
20.55 |
| 2026-06-02 00:00 |
10:00:38.99 |
+15:10:00.6 |
HIP 49010 |
20.48 |
| 2026-06-02 12:00 |
10:00:39.70 |
+15:09:49.1 |
HIP 49010 |
20.41 |
| 2026-06-03 00:00 |
10:00:40.44 |
+15:09:37.4 |
HIP 49010 |
20.34 |
| 2026-06-03 12:00 |
10:00:41.22 |
+15:09:25.5 |
HIP 49010 |
20.28 |
| 2026-06-04 00:00 |
10:00:42.04 |
+15:09:13.4 |
HIP 49010 |
20.23 |
| 2026-06-04 12:00 |
10:00:42.90 |
+15:09:01.1 |
HIP 49010 |
20.18 |
| 2026-06-05 00:00 |
10:00:43.79 |
+15:08:48.6 |
HIP 49010 |
20.14 |
| 2026-06-05 12:00 |
10:00:44.72 |
+15:08:35.9 |
HIP 49010 |
20.11 |
| 2026-06-06 00:00 |
10:00:45.69 |
+15:08:23.1 |
HIP 49010 |
20.08 |
| 2026-06-06 12:00 |
10:00:46.70 |
+15:08:10.1 |
HIP 49010 |
20.07 |
| 2026-06-07 00:00 |
10:00:47.74 |
+15:07:56.9 |
HIP 49010 |
20.06 |
| 2026-06-07 12:00 |
10:00:48.82 |
+15:07:43.5 |
HIP 49010 |
20.06 |
| 2026-06-08 00:00 |
10:00:49.94 |
+15:07:29.9 |
HIP 49010 |
20.07 |
| 2026-06-08 12:00 |
10:00:51.10 |
+15:07:16.1 |
HIP 49010 |
20.10 |
| 2026-06-09 00:00 |
10:00:52.29 |
+15:07:02.2 |
HIP 49010 |
20.13 |
| 2026-06-09 12:00 |
10:00:53.52 |
+15:06:48.1 |
HIP 49010 |
20.17 |
| 2026-06-10 00:00 |
10:00:54.78 |
+15:06:33.8 |
HIP 49010 |
20.23 |
| 2026-06-10 12:00 |
10:00:56.08 |
+15:06:19.3 |
HIP 49010 |
20.29 |
| 2026-06-11 00:00 |
10:00:57.42 |
+15:06:04.7 |
HIP 49010 |
20.37 |
| 2026-06-11 12:00 |
10:00:58.79 |
+15:05:49.9 |
HIP 49010 |
20.46 |
| 2026-06-12 00:00 |
10:01:00.20 |
+15:05:34.9 |
HIP 49010 |
20.56 |
| 2026-06-12 12:00 |
10:01:01.65 |
+15:05:19.7 |
HIP 49010 |
20.68 |
| 2026-06-13 00:00 |
10:01:03.13 |
+15:05:04.4 |
HIP 49010 |
20.81 |
| 2026-06-13 12:00 |
10:01:04.64 |
+15:04:48.9 |
HIP 49010 |
20.96 |
| 2026-06-14 00:00 |
10:01:06.20 |
+15:04:33.2 |
HIP 49010 |
21.11 |
| 2026-06-14 12:00 |
10:01:07.78 |
+15:04:17.4 |
HIP 49010 |
21.29 |
| 2026-06-15 00:00 |
10:01:09.40 |
+15:04:01.3 |
HIP 49010 |
21.47 |
| 2026-06-15 12:00 |
10:01:11.06 |
+15:03:45.2 |
HIP 49010 |
21.67 |
| 2026-06-16 00:00 |
10:01:12.75 |
+15:03:28.8 |
HIP 49168 |
21.85 |
| 2026-06-16 12:00 |
10:01:14.47 |
+15:03:12.3 |
HIP 49168 |
21.85 |
| 2026-06-17 00:00 |
10:01:16.23 |
+15:02:55.6 |
HIP 49168 |
21.87 |
| 2026-06-17 12:00 |
10:01:18.02 |
+15:02:38.8 |
HIP 49168 |
21.89 |
| 2026-06-18 00:00 |
10:01:19.84 |
+15:02:21.8 |
HIP 49168 |
21.92 |
| 2026-06-18 12:00 |
10:01:21.70 |
+15:02:04.7 |
HIP 49168 |
21.97 |
| 2026-06-19 00:00 |
10:01:23.60 |
+15:01:47.4 |
HIP 49168 |
22.02 |
| 2026-06-19 12:00 |
10:01:25.52 |
+15:01:29.9 |
HIP 49168 |
22.09 |
| 2026-06-20 00:00 |
10:01:27.48 |
+15:01:12.3 |
HIP 49168 |
22.17 |
| 2026-06-20 12:00 |
10:01:29.47 |
+15:00:54.5 |
HIP 49214 |
21.64 |
| 2026-06-21 00:00 |
10:01:31.49 |
+15:00:36.6 |
HIP 49214 |
21.07 |
| 2026-06-21 12:00 |
10:01:33.54 |
+15:00:18.5 |
HIP 49214 |
20.49 |
| 2026-06-22 00:00 |
10:01:35.63 |
+15:00:00.3 |
HIP 49214 |
19.90 |