stupid old comet encke doesn't have any eccentricity at all!
the eccentricity will increase.
All orbits are ellipses. Some orbits, like the orbit of the Earth around the Sun, are almost (but not quite) circular. Other objects, like the Moon or Mars, have orbits that are more distinctly oval shaped.Comets have elliptical orbits with very high eccentricity; they are stretched so that they come quite close to the Sun, but still go dozens or hundreds of AU away. Some comets are less severely eccentric. Halley's Comet, for example, only goes out to about 30AU with a period of 76 years, while Comet Hale-Bopp has a period of closer to 2200 years.
Is it an invisible ellipse ... I can't see it
That is Halley's comet, named after English astronomer Edmond Halley,
Halley's Comet
5.2billion
The eccentricity of Hallry's comet is 0.967
the eccentricity of comet tempel-tuttle ia 0.9055
The orbital period of Halley's comet is 75.3 years, and its next visit will be July 28, 2061
0.995. High excentricities (approaching 1) are quite common for comets.
Elliptical paths, just like planets. Typically, but not always, with greater eccentricity.
All orbits are ellipses; this is true for both planets and for comets. Cometary orbits are somewhat extreme ellipses, where the difference between the perihelion (closest to the Sun) is very different from the aphelion (farthest from the Sun) distance. This difference is called "eccentricity". Planets have relatively low eccentricity; for Earth, for example, the eccentricity is only 3%. Some comets don't have an "orbit" at all. An "orbit" implies that the comet will eventually come back. But some comets are "hyperbolic"; their paths aren't an ellipse, but a hyperbola. A hyperbolic comet is a one-time visitor to the solar system; it has fallen in from interstellar space, and will be going back out to interstellar space.
The eccentricity of the Earth is approximately 0.0167.
Eccentricity is only present in ovals and ellipses. A circle is present. The eccentricity of an oval or ellipse is how linear it is.
The eccentricity of Psyche's orbit is 0.140
0.016710220 is the Earth's orbital eccentricity
The eccentricity of the circle is zero.