T Coronae Borealis

[Graeme]

This is a before image of T Coronae Borealis (T CrB), aka the Blaze star, in the centre of the image. (North is to the left) It's a recurrent nova in the constellation Corona Borealis. It's a 10th magnitude double star so not naked eye visible. The more massive White Dwarf star is pulling matter off the larger Red Giant and every 80 years there is a nuclear fusion explosion on its surface which we can then see as a magnitude 3 or even 2 nova. This is about to happen in 2024!

T CrB_Before_EL.jpg

Coronae Borealis is the C shape constellation between Hercules and Boötes, on a line between Vega and Arcturus, about a third of the way from Arcturus. T CrB is just outside the northern crown close to ε CrB. When it goes nova it will be as bright as α CrB, Alphecca, in the crown and completely change the look of the constellation. Definitely something to look out for.

Screenshot 2024-05-11 093903_EL.jpg

Sorry Stuart, you can't play, you will see Vega and Arcturus with nothing in between!


Graeme

[HansV]

Should be spectacular!

[Graeme]

Should be spectacular!

Yes and no!

Yes that a new star will be visible naked eye in the constellation. And yes that it's an event that's been repeating for thousands of years and we're able to see it right here, right now.

But no in that it's not a supernova and 99.99% of people won't notice it at all!

Graeme

[HansV]

For 99,9% of people, anything less than a total solar eclipse is unspectacular...

[PJ_in_FL]

About how long does the peak last?

[Graeme]

About how long does the peak last?

Looks like less than a month or so:

TCrBLightCurve.jpg

https://en.wikipedia.org/wiki/T_Coronae_Borealis

[GeoffW]

About how long does the peak last?

Isn't this post in the wrong thread? It belongs to this post:

I got lucky last night...

[HansV]

@GeoffW: it's about a star going nova, not about (real or fake) auroras.

[GeoffW]

Sorry, something got lost in the translation.

I don't know if @PJ_inFL 's response makes my evil intent clearer

I got lucky last night...
...

What's that got to do with the aurora discussion?

[HansV]

Keep in mind that English is not my first language. Sometimes I fail to get your jokes.

[GeoffW]

Keep in mind that English is not my first language. Sometimes I fail to get your jokes.

For some reason, many native English speakers say the same thing.

[PJ_in_FL]

Keep in mind that English is not my first language. Sometimes I fail to get your jokes.

For some reason, many native English speakers say the same thing.

I try to keep from getting too complex so I don't go over Chris's head.

[ChrisGreaves]

This is about to happen in 2024!

OK, I had missed this. You were writing on May 11th. Have we any idea when this might occur, or is the cycle “every 80 years” not known to the actual month?

Sorry Stuart, you can't play, you will see Vega and Arcturus with nothing in between!

Why is Stuart knocked out of the game? It surely can’t be for security reasons? Please see my image below.

and 99.99% of people won't notice it at all!

Why not? Because it will be invisible to naked eyes like mine?

Looks like less than a month or so:

So there is a fair chance that I will get a few clear nights if the Blaze is before October.

I try to keep from getting too complex so I don't go over Chris's head.

Untitled.jpg

Speaking of which, Stellarium shows me Vega and Arcturus later today. I should go look (although the last two nights have been foggy).
Am I looking in the right part of the sky? Might you drop a pointer to the approximate position relative to my yellow line?
Thanks for any and all elucidations.
Cheers, Chris

[Graeme]

This is about to happen in 2024!

OK, I had missed this. You were writing on May 11th. Have we any idea when this might occur, or is the cycle “every 80 years” not known to the actual month?

Any time between now and the end of the year, probably.

Sorry Stuart, you can't play, you will see Vega and Arcturus with nothing in between!

Why is Stuart knocked out of the game? It surely can’t be for security reasons? Please see my image below.

Because Stuart lives in the London light pollution!

and 99.99% of people won't notice it at all!

Why not? Because it will be invisible to naked eyes like mine?

Because 99% of people don't look up at the sky at night. And the other 0.99% wouldn't notice a new star in Corona Borealis. If you get a clear night in a dark place you can see the C curve shape of Corona Borealis and the brightest star is magnitude 2 Alphecca. (About the same brightness(ish) as the stars in the plough) At the moment T CrB is mag 10 (really dim!) but when it blows it will be as bright as Alphecca and the look of the constellation will be different.

Looks like less than a month or so.

So there is a fair chance that I will get a few clear nights if the Blaze is before October.

Yes, then after October it's quite low in the sky at sunset so more difficult to see. In January it will set before the Sun and we'll miss it!

I try to keep from getting too complex so I don't go over Chris's head.

Speaking of which, Stellarium shows me Vega and Arcturus later today. I should go look (although the last two nights have been foggy).
Am I looking in the right part of the sky? Might you drop a pointer to the approximate position relative to my yellow line?

As requested: (Also, see my Stellarium Snip above (extra point for identifying what the yellow circle in Hercules is. ))

T CrB.jpg

[StuartR]

Sadly, the light pollution here is very bad

[ChrisGreaves]

Sadly, the light pollution here is very bad

As light pollution grows, stars disappear from the night sky. Is Australia at risk of losing the Milky Way?
You are in good company, Stuart.
This morning's article from Australia describes Australian kids from cities being amazed at seeing The Milky Way, all the more peculiar because if we add the ~60 degree inclintaion of the susn's axis to the ~23 degree of the earh's axis, the southern hemisphere is pointing into the heart of the milky way, whereas us plebs in the northern hemisphere are staring outwards past the edge of an oridinary spiral arm towards the netherness.

"Australia has the lowest proportion of land area affected by light pollution among G20 countries. But it's a different story when you look at light pollution per person: Australia has one of the highest rates ..."
I speculate that these two ideas have a common cause: Australia is highly urbanised.
For example one-third the continent's 3,000,000 square miles is Western Australia, and 86% of the state's population live in Perth.

Cheers, Chris

[Graeme]

Here's my whole constellation image of Corona Borealis from last night. I've marked the position of The Blaze Star.

Still no Kabooooom!

CrB 110824_EL.jpg

[ChrisGreaves]

... Australian kids from cities being amazed at seeing The Milky Way, ...

And then is this morning's news:- The making of Australia’s first Dark Sky Community at Carrickalinga
Cheers, Chris

[RonH]

How likely is it that a lot of what we see today in the night sky is no longer there ...

[HansV]

The light from the Suun, Moon and planets such as Mars and Jupiter takes at most a few hours to reach us, so what we see is recent.
The nearest star (except for the Sun) is 4.25 lightyears away, so the light we see now was generated in 2020.
(Fun fact: when I searched for 'nearest star', Google asked for permission to access my location )
The farthest object we can see with naked eye is the Andromeda galaxy, 2.5 million lightyears away. So the light we see now was generated long before Homo Sapiens emerged, and a lot will have happened in that galaxy since then...