Odd, But Interesting Comet

Comet 17p Holmes is a very unusual comet. Of the comets I've observed, I've never seen anything like this one.

It is easy to find with the naked eye but has no sign of a tail.

With the unaided eye, it appears as a star, at least in my light-poluted back yard.

In a pair of binoculars, with 15x power, the "star" is clearly not a star. It appears fuzzy and bright.

Through a 3.5 Questar, the comet appears very bright. It almost looks like a bright eliptical galaxy. It has a shape of a planetary nebula or a globular cluster, but it is far brighter. There is no nucleus. No tail extends in one particular direction With averted vision, there is a brighter core with a dimmer halo. The halo is evenly distributed around the equally evenly distributed core. There is a distinct greenish color.

In a photograph taken with the 3.5 Questar, the comet does reveal a nucleus with a hint of a tail.
The lack of the traditional tail comes from the fact that we are looking straight into the comet, head on, as demonstrated in the computer simulation below.

You can see from this computer simulation that 17p/Holmes does not have a large orbit. Unlike many great comets, it does not go beyond Pluto, or even beyond Jupiter. It is currently moving away from the sun.

The brightness of the comet is due to a sudden "outburst." Comet outbursts happen from time to time, and Holmes has done this before. The outburst can be due to a sudden outgassing or a sudden release of particles from the comet. Holmes was discovered in November, 1892, and has had a similar brightening outburst in the year of its discovery. It has an orbit of 6.9 years, so it is possible to see this comet several times in one's lifetime.

Comet Holmes is easy to find with the naked eye. I took the image below with a Canon Rebel, with a 60 second exposure.




Here the comet formed a triangle with Delta and Alpha in Perseus (Alpha is also known as Mirfak). Each night this star-like comet should move.