Meteors associated with the π-Puppid Meteor Shower may be visible from parts of Earth between Wednesday 15 and Tuesday 28 April this year (2020), with peak activity on Thursday 23 April. However the shower will not be visible from latitudes greater than about 30° north, and will not produce many meteors even at lower latitudes, although peak activity will come only a day after the New Moon, so visibility should be reasonably good. In areas where the shower is visible, the meteors will appear to radiate from a point in the constellation of Puppis, close to the star Sigma Puppis (Hadir) and best viewing will be in the early evening.
The radiant point of the π-Puppid Meteor Shower. Universe Guide/Night Vision.
Meteor showers are thought to be largely composed of material from the
tails of comets. Comets are composed largely of ice (mostly water and
carbon
dioxide), and when they fall into the inner Solar System the outer
layers of this boil away, forming a visible tail (which always points
away from the Sun, not in the direction the comet is coming from, as our
Earth-bound experience would lead us to expect). Particles of rock and
dust from within the comet are freed by this melting (strictly
sublimation) of the comet into the tail and continue to orbit in the
same path as the comet, falling behind over time.
The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.
The π-Puppid Meteor Shower is associated with the comet 26P/Grigg–Skjellerup, a Short Period Comet that formerly crossed the Earth's orbit every five years, with peak activity in the shower occurring the April after such a passage. However in 1999 the comet's orbit was perturbed by a close encounter with the planet Jupiter, so that it no longer comes closer to the Sun than 1.12 AU (i.e. 12% further from the Sun than the planet Earth) so that the meteor shower is no longer 'topped up' by returns of the comet, and grows fainter each year.
26P/Grigg–Skjellerup is named after New Zealand astronomer John Grigg who observed it in 1902 and the South Africa-based Australian astronomer John Skjellerup, who witnessed it in 1922. However, it was later realised that the comet was first sighted by the French astronomer Jean-Louis Pons in 1808, so he should be given credit for its discovery. The designation 26P implies that
it was the 26th Periodic Comet (Periodic Comets are defined as comets
with orbital periods of less than 200 years).
Comet 26P/Grigg–Skjellerup, imaged on 29 June 1992 from the European Southern Observatory in Chile. ESO/Wikimedia Commons.
Comet 26P/Grigg–Skjellerup currently completes one orbit every 1939 days (5.31 years) on
an eccentric orbit tilted at 22.4° to the plane of the Solar System,
that takes it from 1.12 AU from the Sun (112% of the
average distance at which the Earth orbits the Sun) to 4.97 AU from the
Sun
(4.97 times as far from the Sun as the Earth, and slightly inside the orbit of Jupiter). As a
comet with a period of less
than 20 years with an orbit angled at less than 30° to the plane of the
Solar System, 26P/Grigg–Skjellerup is considered to be a Jupiter Family Comet.
26P/Grigg–Skjellerup was visited by the European Space Agency's Giotto Probe in 1992, passing within 200 km of the comet, although it was able to return little data on the body as many of its instruments were damaged during an earlier encounter with Halley's Comet.
See also...
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