| Parameter |
Value |
| Designation |
19P/Borrelly |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-02-01T18:20:14.879040Z |
| Orbit solution date (soln_date, UTC) |
2024-12-30T09:03:27Z |
| Obs used |
2452 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
14.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-03-06.0000000 |
| e |
0.63791428 |
| q (au) |
1.306030 |
| a (au) |
3.606965 |
| i (deg) |
29.318662 |
| Ω (om, deg) |
74.300843 |
| ω (w, deg) |
351.861606 |
| M (ma, deg) |
312.122920 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.210 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.210 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.962 |
| k |
0.999 |
| δ90 |
1.000 |
| 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 |
| 2021-02-02 |
2021-07-04 |
-78.0808 |
+33.211 |
| 2021-07-04 |
2022-02-01 |
+6.5636 |
-1.743 |
| 2022-02-01 |
2022-05-18 |
-2.2914 |
-0.440 |
| 2022-05-18 |
2024-05-02 |
+2.9727 |
-2.179 |
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 |
17:21:56.57 |
-26:43:52.2 |
HIP 84931 |
15.40 |
| 2026-06-01 12:00 |
17:21:35.30 |
-26:44:27.2 |
HIP 84931 |
14.53 |
| 2026-06-02 00:00 |
17:21:13.95 |
-26:45:01.8 |
HIP 84931 |
15.20 |
| 2026-06-02 12:00 |
17:20:52.54 |
-26:45:36.0 |
HIP 84851 |
13.52 |
| 2026-06-03 00:00 |
17:20:31.06 |
-26:46:09.8 |
HIP 84851 |
13.18 |
| 2026-06-03 12:00 |
17:20:09.52 |
-26:46:43.1 |
HIP 84851 |
14.53 |
| 2026-06-04 00:00 |
17:19:47.93 |
-26:47:16.1 |
HIP 84851 |
17.19 |
| 2026-06-04 12:00 |
17:19:26.27 |
-26:47:48.7 |
HIP 84851 |
20.67 |
| 2026-06-05 00:00 |
17:19:04.57 |
-26:48:20.9 |
HIP 84605 |
21.75 |
| 2026-06-05 12:00 |
17:18:42.81 |
-26:48:52.6 |
HIP 84605 |
17.99 |
| 2026-06-06 00:00 |
17:18:21.00 |
-26:49:24.0 |
HIP 84605 |
14.89 |
| 2026-06-06 12:00 |
17:17:59.16 |
-26:49:54.9 |
HIP 84605 |
12.94 |
| 2026-06-07 00:00 |
17:17:37.27 |
-26:50:25.4 |
HIP 84605 |
12.70 |
| 2026-06-07 12:00 |
17:17:15.34 |
-26:50:55.5 |
HIP 84605 |
14.25 |
| 2026-06-08 00:00 |
17:16:53.38 |
-26:51:25.2 |
HIP 84605 |
17.13 |
| 2026-06-08 12:00 |
17:16:31.38 |
-26:51:54.4 |
HIP 84478 |
19.70 |
| 2026-06-09 00:00 |
17:16:09.36 |
-26:52:23.2 |
HIP 84405 |
19.59 |
| 2026-06-09 12:00 |
17:15:47.31 |
-26:52:51.7 |
HIP 84405 |
17.83 |
| 2026-06-10 00:00 |
17:15:25.24 |
-26:53:19.6 |
HIP 84314 |
16.83 |
| 2026-06-10 12:00 |
17:15:03.15 |
-26:53:47.2 |
HIP 84314 |
12.11 |
| 2026-06-11 00:00 |
17:14:41.04 |
-26:54:14.4 |
HIP 84314 |
7.67 |
| 2026-06-11 12:00 |
17:14:18.92 |
-26:54:41.1 |
HIP 84314 |
4.49 |
| 2026-06-12 00:00 |
17:13:56.79 |
-26:55:07.4 |
HIP 84314 |
5.53 |
| 2026-06-12 12:00 |
17:13:34.65 |
-26:55:33.3 |
HIP 84314 |
9.49 |
| 2026-06-13 00:00 |
17:13:12.51 |
-26:55:58.7 |
HIP 84192 |
9.56 |
| 2026-06-13 12:00 |
17:12:50.37 |
-26:56:23.8 |
HIP 84192 |
5.68 |
| 2026-06-14 00:00 |
17:12:28.23 |
-26:56:48.4 |
HIP 84192 |
4.72 |
| 2026-06-14 12:00 |
17:12:06.10 |
-26:57:12.7 |
HIP 84144 |
5.43 |
| 2026-06-15 00:00 |
17:11:43.98 |
-26:57:36.5 |
HIP 84144 |
7.77 |
| 2026-06-15 12:00 |
17:11:21.87 |
-26:57:59.9 |
HIP 84144 |
11.84 |
| 2026-06-16 00:00 |
17:10:59.78 |
-26:58:22.8 |
HIP 84144 |
16.39 |
| 2026-06-16 12:00 |
17:10:37.71 |
-26:58:45.4 |
HIP 84144 |
21.11 |
| 2026-06-17 00:00 |
17:10:15.66 |
-26:59:07.6 |
HIP 83963 |
18.88 |
| 2026-06-17 12:00 |
17:09:53.64 |
-26:59:29.3 |
HIP 83963 |
17.54 |
| 2026-06-18 00:00 |
17:09:31.65 |
-26:59:50.7 |
HIP 83878 |
15.61 |
| 2026-06-18 12:00 |
17:09:09.69 |
-27:00:11.7 |
HIP 83878 |
12.42 |
| 2026-06-19 00:00 |
17:08:47.77 |
-27:00:32.2 |
HIP 83878 |
10.63 |
| 2026-06-19 12:00 |
17:08:25.89 |
-27:00:52.4 |
HIP 83878 |
10.93 |
| 2026-06-20 00:00 |
17:08:04.05 |
-27:01:12.2 |
HIP 83878 |
13.18 |
| 2026-06-20 12:00 |
17:07:42.26 |
-27:01:31.6 |
HIP 83878 |
16.58 |
| 2026-06-21 00:00 |
17:07:20.52 |
-27:01:50.6 |
HIP 83878 |
20.57 |
| 2026-06-21 12:00 |
17:06:58.83 |
-27:02:09.2 |
HIP 83878 |
24.85 |
| 2026-06-22 00:00 |
17:06:37.19 |
-27:02:27.4 |
HIP 83674 |
28.51 |