NOVA SGR 2008  - Joseph Brimacombe

Nova Sagittarius 2008 UPDATE

24 Apr , 2008

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Since the initial alert for the latest nova in Sagittarius, folks the world over have been anxious for darkness to arrive and their chance at spotting this cosmic wonder firsthand. Thanks to our good friends at Macedon Ranges Observatory, Universe Today readers are about to see the latest nova in Sagittarius revealed and learn just what is a nova.

One thing is certain, both professional and amateur astronomers have something in common – curiosity. Unfortunately, because many of us live where skies seem to be perpetually cloudy or don’t always have the equipment to view a late breaking astronomy alert object, it becomes even more imperative to be able to call upon others in different regions of the world. It certainly is a true pleasure to have friends down under! So now that we see it… What is a nova?

The word nova is Latin for “new star”. Astronomers assign the term nova to stars that have a rapid increase in brightness. These stars are usually far too dim to be seen unaided and may often become the brightest object – besides the Sun and Moon – in the sky!

Novae themselves are stars that have been quiet for many years, and suddenly decided to reignite their nuclear fusion process. All stars have fusion occurring in their core – processing hydrogen into helium and releasing energy. When this fuel is expended, stars like our sun simply shed their outer layer and continue on as small, hot, white dwarf stars. They are basically dead… Their fuel gone.

Unlike our own Sun, most stars are a binary system – two stars that closely orbit each other. If one of these stars should happen to be a white dwarf and the other starts to evolve into a red giant, the white dwarf can begin attracting gas towards itself by means of gravity. What type of gas? Hydrogen! When the hydrogen stolen from the red giant reaches the surface of the incredibly hot white dwarf, it rapidly ignites. What’s born is an incredibly huge nuclear explosion on the white dwarf’s surface and we see it as a nova!

NOVA SGR 2008 24April - Joseph Brimacombe

Using a 12″ Ritchey Chretien Optical Systems telescope, Joe Brimacombe set to work imaging the latest nova for us to see. By comparing this photo with the 19 April Sagittarius Image you can see how quickly the white dwarf ignited!

Nova Sgr 19April2008 Joseph Brimacombe Image details are as follows: STL11000 camera; BRC 250; image scale 1.46 asec/px; image is 97 amin across; nova is centre star; stack 6 x 300 Ha; false colour.


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Cynthia
Guest
Cynthia
April 24, 2008 3:24 PM

What exactly is meant by the hydrogen “igniting” on the surface of a white dwarf. Does it mean that the hydrogen is “burning” in some sort of chemical oxidation process? Or is it undergoing fusion with other hydrogen on the surface of the white dwarf?

skyweek
Member
April 24, 2008 3:33 PM

The article doesn’t make it clear enough by how much Nova Sgr 2008 has brightened since it was discovered: It is almost a naked-eye object now!

ed
Guest
ed
April 24, 2008 3:51 PM

@ cynthia:
“igniting” —> fusing (as in fision)

Bjarne
Guest
Bjarne
April 24, 2008 8:37 PM

@ Tammy: Good fer ya girl!! If a person cannot find their own stories but, as you point out “… point back to their own webpage” then it seems that UT folks ARE doing their job and it’s unfortunate that others are just to d*** lazy to foot slog for themselves.

Fraser: Thanks for the hard work you guys… and gals 8) do here! Keep it up please!

Ian O'Neill
Member
April 25, 2008 4:49 AM

Oh Tammy, it makes me want to buy a telescope and get out there! Wonderful observations – inspirational reporting.

(and good for you by the way, Daniel spends way too much time promoting his website than actually adding news, sad really)

Looking forward to seeing the next astronomy update (I’ll be one step closer to a brand new telescope then grin )

Cheers, Ian

Don Alexander
Member
Don Alexander
April 25, 2008 6:08 AM
Ahem… If I might make two corrections. Firstly, “nova” does not mean “new star”, it just means “new”. The correct old term is “stella nova”. In the days of more or less naked eye observing, a stella nova was any star that appeeared out of nowhere. Today, a “nova” classifies, as you write, a binary system with a white dwarf that has accretion-induced fusion episodes. Second comment: You write: “When the hydrogen stolen from the red giant reaches the surface of the incredibly hot white dwarf, it rapidly ignites. What’s born is an incredibly huge nuclear explosion on the white dwarf’s surface and we see it as a nova!” This is not totally correct. The hydrogen stream from… Read more »
Ian O'Neill
Member
April 25, 2008 4:34 PM

When I’m back in the US I’ll be sure to sign for one of your telescopes! grin I’ll have to pop to the desert though, damned LA lights and smog… That’s the great thing about reading your articles, lets me turn of my physics brain and get excited about actually observing the things I teach… I bet you’ll find a lot of frustrated astronomers in the UK – not many cloudless nights sad In theory I can do astronomy…

Looking forward to your next virtual astronomy tour!

Ian smile

Tammy Plotner
Guest
Tammy Plotner
April 25, 2008 4:00 PM

I don’t mind your comments a bit, Don. I’m sure if you regularly read my stuff that you’ve probably gathered this was “aimed down” for a slightly younger audience. So good for you for science-ing it up! smile

And thank you, Ian… That’s been coming for some time and I’m very happy to know that my friends think no less of me. Tell me where you live and I’ll send one of my scopes for you to try out… Bless UPS!

skyweek
Member
April 29, 2008 4:29 PM
Since feed readers show newer stories first, this was the one I saw before the older “is brightening” story which was ‘below the fold’. It did not refer to the older one in the text (only the very first one) nor did it repeat the key fact (steep rise to 6.5 mag.). Nor did it give a date for the new image shown (which also has a different exposure setting/grey scale than the April 19 pic, making a comparision hard). Nor does the link behind the observatory lead to the original images. Now who’s sloppy here … By the way, an editing feature for one’s own comments would help a lot (most blogs provide it): There was no… Read more »
John Dankowski
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John Dankowski
May 1, 2008 12:05 AM

My ignorance is showing (it does often), but as I scroll through your pages (including the red link “subscribe”), I don’t see where I need to sign in to subscribe to Universe Today. Can you assist me?

Thank you (from Taiwan)(where I’m trying to encourage interest in Space programs).

John Dankowski

5CardCharlie
Guest
5CardCharlie
May 28, 2008 11:42 AM

>ed Says:
>April 24th, 2008 at 3:51 pm
>@ cynthia:
>”igniting” —> fusing (as in fision)

haha fusion and fission aren’t exactly the same thing… more like the complete opposite. Next time you want to explain something to someone, ask yourself if it’s a topic you know the slightest thing about.

wpDiscuz