C/2017 E4 Lovejoy
more info
Comet C/2017 E4 was discovered on 9 March 2017 by Terry James Lovejoy (Birkdale, Queensland, Australia), that is 1.5 month before its perihelion passage, and was followed only to 24 April 2017, because next it disrupted completely ( Yoshida ).Comet had closest approach to the Earth on 30 March 2017 (0.606 au, more than three weeks before the perihelion passage).
Due to destruction process, the GR solution based on the entire available data arc (solution 'a1', spanning over 45 days in a range of heliocentric distances from 1.10 au to 0.49 au)gives spectacular picture of time distribution of residuals (see picture associated with solution 'a1'). The NG solution ('n1') based on constant NG parameters reduces these trends in [O-C]; however,some trends are still visible (see [O-C] picture for 'n1' solution). The obtained NG parameters are consistent with those obtained at JPL from the same data arc where the normal NG parameter is assumed to be zero in both cases. Comparing the time distribution of residuals [O-C] for both types of orbits (GR and NG), it can be concluded that the nucleus disruption process could be started at the beginning of April.So, the assumption of the constancy of NG parameters is not a proper assumption for the entire data arc. Therefore, despite the extremely short data arc, we indicate the GR 'a3' solution as preferred.Unfortunately, this orbit is poorly determined (large orbital uncertainties).
GR assumption applied for the entire data arc gives original hyperbolic orbit (original 1/a = -2615.93±83.22); however, GR orbit based on shorter data arc (solution 'a3') results in original semimajor axis of about 1200–3600 au (uncertainty of one sigma is applied).
See also: Faggi et al. 2018 and Sekanina 2019.
Due to destruction process, the GR solution based on the entire available data arc (solution 'a1', spanning over 45 days in a range of heliocentric distances from 1.10 au to 0.49 au)gives spectacular picture of time distribution of residuals (see picture associated with solution 'a1'). The NG solution ('n1') based on constant NG parameters reduces these trends in [O-C]; however,some trends are still visible (see [O-C] picture for 'n1' solution). The obtained NG parameters are consistent with those obtained at JPL from the same data arc where the normal NG parameter is assumed to be zero in both cases. Comparing the time distribution of residuals [O-C] for both types of orbits (GR and NG), it can be concluded that the nucleus disruption process could be started at the beginning of April.So, the assumption of the constancy of NG parameters is not a proper assumption for the entire data arc. Therefore, despite the extremely short data arc, we indicate the GR 'a3' solution as preferred.Unfortunately, this orbit is poorly determined (large orbital uncertainties).
GR assumption applied for the entire data arc gives original hyperbolic orbit (original 1/a = -2615.93±83.22); however, GR orbit based on shorter data arc (solution 'a3') results in original semimajor axis of about 1200–3600 au (uncertainty of one sigma is applied).
See also: Faggi et al. 2018 and Sekanina 2019.
| solution description | ||
|---|---|---|
| number of observations | 282 | |
| data interval | 2017 03 09 – 2017 03 31 | |
| data arc selection | data generally limited to pre-perihelion (PRE) | |
| range of heliocentric distances | 1.1 au – 0.724au | |
| detectability of NG effects in the comet's motion | comet lost close to perihelion or split comet | |
| type of model of motion | GR - gravitational orbit | |
| data weighting | YES | |
| number of residuals | 556 | |
| RMS [arcseconds] | 0.62 | |
| orbit quality class | 3a | |
| orbital elements (heliocentric ecliptic J2000) | ||
|---|---|---|
| Epoch | 2017 05 07 | |
| perihelion date | 2017 04 23.29805504 | ± 0.00229541 |
| perihelion distance [au] | 0.49370268 | ± 0.00002042 |
| eccentricity | 0.99996466 | ± 0.00013584 |
| argument of perihelion [°] | 87.206023 | ± 0.005544 |
| ascending node [°] | 223.182635 | ± 0.001898 |
| inclination [°] | 88.181665 | ± 0.000264 |
| reciprocal semi-major axis [10-6 au-1] | 71.57 | ± 275.15 |
Upper panel: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line — the moment of perihelion passage.
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).