Mystery bubble, help needed

[Jacob Bassoe]

Dear ARAS members

Recently I discovered an object that looked like a Planetary nebula when working on my image of NGC 6820, see the discovery photo here http://jbassoe.dk/astro/images/NGC6820s ... yboble.jpg

Since the discovery I've gotten a lot of help from fellow amateur astronomers and from professional astronomers. Now there’s a small group of people trying to find out more abut this object.

Many theories and speculations later we have come to the conclusion that it's probably not a PN. We have had, and still have, correspondence with a couple of astrophysicists around Europe and they show interest in the object. So we are still trying to determine what this object is.

The next step for us is to get some spectral information of the "bubble", so we have data to determine if it’s an object that’s need further investigations. We are considering, with help from Danish astronomers, to put in a FastTrack request for a spectral observations on The Nordic Optical Telescope (NOT).

This is why I'm contacting you, we need spectral information. Before we put in the request we need to get as much data as possible about the object, so there is a better basis for deciding whether to make further observations with NOT

It's a very faint object, brightness around mag. 16. Would it be possible to get spectra in the visible domain with amateur equipment? And if so, will you consider giving it a try?

Of course credits will be mentioned in any publication that would come from this.

Here is a link to the article that describes our progress and unanswered questions so far.
http://jbassoe.dk/astro/images/Boblen_f ... 131018.pdf

Kind regards
Jacob Bassøe



PS: It’s now an open investigation that’s discussed on on a Danish astro forum, http://www.astro-forum.dk

[Paolo Berardi]

Dear Jacob, this is very interesting, thank you for sharing. It is a very faint target for amateur spectroscopy but I think not impossible. Christian Buil was able to capture the spectrum of OU4, a weak nebula discovered in May 2011 by Nicolas Outters. See here:

http://www.spectro-aras.com/forum/viewt ... ?f=6&t=409

Probably is required large aperture and fast focal ratio telescope together with a well coupled low dispersion specrograph. Possible nebular lines should be captured. Could also be useful analyze the spectrum of central star that, if progenitor of a PLN, might be peculiar.

I'm not sure I have the best equipment for this work but there are many expert spectroscopists here.

Clear sky
Paolo

[Lars Zielke]

Dear all

A little update and again a call for help.

An expert in PN found the object interesting. It could be a be a combination of ionization and scattered star light. In the IPHAS images there a number of objects which is a bit like this, faint, quite round and structure less and with much brighter central stars than might be expected for a PN. Some may be post-AGB stars, and others may be Strömgren spheres where a star ionizes unrelated ISM.

It is expected to be a B-type star, but my attempts with low-res SA spectre doesn’t point in that direction at all. That could be contamination form stars in the field or extreme reddening, but with my current equipment situation and weather situation I can't do better.

So it’s urgently needed to get a god spectra of the star, if we should apply for a NOT spectre before it’s to late this year.

Please help us. Credits will of course be given when a publication come out of this.

We still need a spectrum of the nebula to determine the Ha/Hb ratio to find the extinction. The IPHAs images shows the nebula clearly in 120 sec. integration in Ha, but I think that it’s probably to faint for amateur telescopes, what do you think?