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11/11/2011

Pease 1 or Kuestner 648 in Messier 15





















Image taken from the Hubble Space Telescope

I was going to just edit my last blog post, but I decided instead to enter this information on its own. If you go to the blog post before this one, dated November 6th, 2011, I have entered my information on finding the planetary nebula in the globular cluster Messier 15 in Pegasus. This post is to share the information on how to find it with those who may want to go after it themselves.

Here is the link to the Blackskies.org findercharts for Pease 1. These are the best you can get and though it eats some ink up, I recommend that you print them out and use them as you go after them. I did and it really did help.

In this link you will find actual observations that are written on the BlackSkies.org site from amateurs who successful chased down this object. I post these as you may find them useful, especially the photo on the bottom on the page. That last recorded observation on that website is 10/7/2004.

The wonderful Czech amateur astronomer Leos Ondra has a 12 year old article on Pease 1 located here that is still a wonderful read. Even if you have no intention of looking at this object, you should read the article as he touches on why so few planetary nebula are found in globular clusters (has something to do with these things called pulsars and the amount of them and the wind they create . . . but go read the article). For that matter you may find some of his articles on his web page interesting so this is the link to them. I look forward to reading his article on what was then a new variable in the Dumbbell Nebula; the article on Wilhelm Tempel, the discoverer of the Pleiades, and his article on Messier 5 and its variables. Be warned, his links on his webpage are no good for some of the article but I simply googled his first and last name and the name of the article and found them. Here is the one on Messier 5 and its variables. Looks like I have some nice quick and enjoyable reading for the snowy nights this weekend where I live here in Utah.

Hubble checked out M15 and Pease1 and here is a link to the images (yes, I think it looks like a tiny dumbbell or even a tie-fighter from Star Wars). From the site I share two comments. The first is that "the surface temperature of the central star of K 648 is about 70,000 degrees Fahrenheit (40,000 degrees Celsius), and analysis of the Hubble data indicates that the star's remaining mass is only 60 percent that of our Sun. The star's outer layers were ejected some 4,000 years ago (i.e., before the light we see was emitted)."

There is a mystery to how the planetary formed because "at the present time, the most massive stars remaining in M15 have about 80 percent of the mass of our Sun, a fact that makes the existence of a planetary nebula like K 648 something of a mystery. The Hubble images used to make this image were taken to test the idea that the progenitor of K 648 may have "borrowed" some mass from a nearby stellar companion. No such companion was revealed by Hubble, so the mystery remains unsolved. One possibility is that the progenitor of K 648 was two stars, which then merged together to become the single star now seen at the center of the nebula"

Finally, Steve Gottlieb at this link offers a finder chart via images to find Pease 1 and some other fun faint early winter items. I enjoy Steve's stuff a lot and encourage you to read that piece also.

There's other images available online with descriptions if you search under Pease 1. I just wanted to kinda of bring all of them together here. Hope someone finds it useful.