| 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) |
| 2026-03-26 00:00 |
17:45:45.31 |
-24:55:53.2 |
HIP 86866 |
18.80 |
| 2026-03-26 12:00 |
17:45:47.67 |
-24:56:42.7 |
HIP 86866 |
19.78 |
| 2026-03-27 00:00 |
17:45:49.84 |
-24:57:32.3 |
HIP 86866 |
20.73 |
| 2026-03-27 12:00 |
17:45:51.81 |
-24:58:22.0 |
HIP 86866 |
21.66 |
| 2026-03-28 00:00 |
17:45:53.59 |
-24:59:11.8 |
HIP 86866 |
22.57 |
| 2026-03-28 12:00 |
17:45:55.17 |
-25:00:01.6 |
HIP 86866 |
23.45 |
| 2026-03-29 00:00 |
17:45:56.56 |
-25:00:51.5 |
HIP 86866 |
24.31 |
| 2026-03-29 12:00 |
17:45:57.75 |
-25:01:41.5 |
HIP 86866 |
25.14 |
| 2026-03-30 00:00 |
17:45:58.74 |
-25:02:31.6 |
HIP 87093 |
25.35 |
| 2026-03-30 12:00 |
17:45:59.53 |
-25:03:21.8 |
HIP 87093 |
24.90 |
| 2026-03-31 00:00 |
17:46:00.13 |
-25:04:12.0 |
HIP 87093 |
24.52 |
| 2026-03-31 12:00 |
17:46:00.53 |
-25:05:02.4 |
HIP 87093 |
24.20 |
| 2026-04-01 00:00 |
17:46:00.73 |
-25:05:52.8 |
HIP 87093 |
23.95 |
| 2026-04-01 12:00 |
17:46:00.73 |
-25:06:43.2 |
HIP 87093 |
23.77 |
| 2026-04-02 00:00 |
17:46:00.53 |
-25:07:33.8 |
HIP 87093 |
23.67 |
| 2026-04-02 12:00 |
17:46:00.12 |
-25:08:24.4 |
HIP 87093 |
23.64 |
| 2026-04-03 00:00 |
17:45:59.52 |
-25:09:15.1 |
HIP 87093 |
23.68 |
| 2026-04-03 12:00 |
17:45:58.71 |
-25:10:05.9 |
HIP 87093 |
23.80 |
| 2026-04-04 00:00 |
17:45:57.71 |
-25:10:56.7 |
HIP 87093 |
24.00 |
| 2026-04-04 12:00 |
17:45:56.49 |
-25:11:47.7 |
HIP 87093 |
24.27 |
| 2026-04-05 00:00 |
17:45:55.08 |
-25:12:38.7 |
HIP 87093 |
24.62 |
| 2026-04-05 12:00 |
17:45:53.46 |
-25:13:29.7 |
HIP 87093 |
25.05 |
| 2026-04-06 00:00 |
17:45:51.64 |
-25:14:20.9 |
HIP 87093 |
25.54 |
| 2026-04-06 12:00 |
17:45:49.61 |
-25:15:12.1 |
HIP 87093 |
26.11 |
| 2026-04-07 00:00 |
17:45:47.37 |
-25:16:03.3 |
HIP 87093 |
26.75 |
| 2026-04-07 12:00 |
17:45:44.93 |
-25:16:54.6 |
HIP 87093 |
27.45 |
| 2026-04-08 00:00 |
17:45:42.28 |
-25:17:46.0 |
HIP 87093 |
28.22 |
| 2026-04-08 12:00 |
17:45:39.43 |
-25:18:37.5 |
HIP 87093 |
29.05 |
| 2026-04-09 00:00 |
17:45:36.36 |
-25:19:29.0 |
HIP 87009 |
29.87 |
| 2026-04-09 12:00 |
17:45:33.09 |
-25:20:20.6 |
HIP 87009 |
29.52 |
| 2026-04-10 00:00 |
17:45:29.61 |
-25:21:12.2 |
HIP 87009 |
29.24 |
| 2026-04-10 12:00 |
17:45:25.93 |
-25:22:03.9 |
HIP 87009 |
29.02 |
| 2026-04-11 00:00 |
17:45:22.03 |
-25:22:55.6 |
HIP 87009 |
28.88 |
| 2026-04-11 12:00 |
17:45:17.92 |
-25:23:47.4 |
HIP 87009 |
28.83 |
| 2026-04-12 00:00 |
17:45:13.61 |
-25:24:39.2 |
HIP 87009 |
28.86 |
| 2026-04-12 12:00 |
17:45:09.08 |
-25:25:31.1 |
HIP 87009 |
28.98 |
| 2026-04-13 00:00 |
17:45:04.35 |
-25:26:23.0 |
HIP 87009 |
29.20 |
| 2026-04-13 12:00 |
17:44:59.40 |
-25:27:14.9 |
HIP 87009 |
29.52 |
| 2026-04-14 00:00 |
17:44:54.24 |
-25:28:06.9 |
HIP 87009 |
29.95 |
| 2026-04-14 12:00 |
17:44:48.88 |
-25:28:58.9 |
HIP 87009 |
30.47 |
| 2026-04-15 00:00 |
17:44:43.30 |
-25:29:51.0 |
HIP 87009 |
31.10 |
| 2026-04-15 12:00 |
17:44:37.51 |
-25:30:43.1 |
HIP 87009 |
31.83 |
| 2026-04-16 00:00 |
17:44:31.51 |
-25:31:35.2 |
HIP 87009 |
32.66 |