Cosmic Background: Corona Borealis

Join Jordan & Kit as they explore the awesome astronomy and other cosmic background of the constellation Corona Borealis! 

Episode Transcript: https://www.starrytimepodcast.com/episode-transcripts.html

Episode Transcript

Jordan: Hi, I'm Jordan. (00:15):
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Kit: And I'm Kit. (00:17):
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Jordan: Welcome to Starry Time. (00:18):
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Where stars plus lines.

Kit: Equals stories. (00:22):
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Jordan: For our final series of episodes this season, we'll be exploring the constellation Corona (00:23):
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Borealis, the northern Crown.

Kit: This week's episode will be focused on the astronomy and other cosmic background of this (00:33):
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constellation.

Jordan: Corona borealis is a relatively small constellation. (00:39):
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It ranks 73rd in size among the IAUrecognized 88 modern constellations, and it
is only slightly larger than the evensmaller constellation that we started our
second season.

Kit: Quests and Curses! (00:58):
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Jordan: which was, of course, the southern crown, Corona Australis, which ranks 80th out of the (01:00):
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88.

Kit: And these are the smallest constellations that we've covered by a lot. (01:07):
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And it is also one of Ptolemy's great.

Jordan: Great great great great great great great great great great great great great great. (01:15):
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Kit: 48 constellations which he identified in his second century text, the Almagest. (01:20):
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Jordan: All right, Kit, let's start with your first impressions of this little constellation. (01:27):
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What did it look like to you?

Kit: It's a "U". (01:34):
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I mean, I'm I'm back to letters because it'sa "U".

Jordan: I mean, I don't blame you for that one. (01:40):
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It's a "U." You're right. It's a "U".

Kit: Yeah. I just can't really get to Northern Crown. (01:47):
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Can you get there? I don't I don't know

Jordan: I mean to me the semicircle aspect of it definitely reminds me of something jewelry (01:53):
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like, like, but to me it looks like anecklace or a tiara.
It doesn't look like a crown to me, butYeah.
So, like, if you wrote a "U" in a veryclassy font.

Kit: These descriptions are probably not helpful. (02:14):
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So you can find this constellation -- it'svisible between positive 90 and -50
latitudes, and it's highest in the night skyin the northern Hemisphere in July.

Jordan: Coming right up. (02:28):
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It is between Hercules, who we coveredearlier this season, and the constellation
Boötes. If you're not sure where to findthese specific constellations, you can look
for the bright stars of Arcturus, which isin Boötes, and Vega, which is in Lyra.

Kit: Which we also have covered this season. (02:46):
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Jordan: It's been a great season, Quests and curses. (02:48):
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But if you draw a line between those twostars in between them you will find Corona
Borealis.

Kit: Getting a bit more technical, which we love to do here. (03:00):
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It has a right ascension of about 16 hoursand a declination of 30 degrees.

Jordan: We love getting technical here. (03:10):
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All right, now we know where to find it andwhat it looks like.
Let's talk about some of the stars here.
This constellation is comprised of sevenmain stars.
And Kit, I am hoping beyond hope that ourfavorite historical lawyer slash astronomer

(03:30):
slash icon, Johann Bayer, goes out with areal crown of his own this season.
Could you please make this vision come truefor me?
What is the brightest star of thisconstellation?

Kit: Corona borealis doesn't actually have very many bright stars. (03:45):
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And the stars that comprise the crown itselfare all fourth magnitude except the brightest
one, which clocks in with an apparentmagnitude of 2.24 and is designated as Alpha
Coronae Borealis.

Jordan: Great job. (04:05):
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I mean, it doesn't hurt that it'ssignificantly brighter than every other star,
but hey, Johann, a win is a win and we loveto see it go out on top.
Before you go on, though, Kit, I did alittle number crunching before this final
cosmic background of season two.
So this season we covered 11 constellationsand Johann identified the brightest star in.

(04:33):
Well, do you want to take a guess whatpercent of the time.

Kit: Johann got it right? (04:37):
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Jordan: That Johann got it right, yes. (04:38):
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Kit: Okay. So I feel like this season he did better than 50 over 50. (04:41):
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Like, I feel like this season was betterthan the first season.
Maybe. Like, maybe, you know, not to just godown the middle.
I'll say like 60% correct.

Jordan: Well, Kit, our guy Johann. (04:57):
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Went an astoundingly okay, nine for 11, 82%correct.

Kit: Well, that's a that's a B minus. (05:09):
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So that kind of that kind of feels right.

Jordan: Hey, if you can get in the history books the solid B-minus effort, Johann, carry on. (05:14):
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Kit: So it's officially named Alphecca, which is from an Arabic phrase meaning the bright star (05:20):
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of the broken ring.

Jordan: Ooh. The broken ring does sound like a book series that we need to read. (05:29):
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I'm ready for it.

Kit: Yeah, it has very epic fantasy vibes. (05:36):
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So Alpha Coronae Borealis is actually aneclipsing binary star system, and it's
located in the center of the U shape of theconstellation.
It's 75 light years from Earth, and it'scomprised of two main sequence stars.

Jordan: And we did learn about eclipsing binary stars in our cosmic background of Perseus. (05:54):
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Didn't beta Persei, aka the Demon Star,include an eclipsing binary?

Kit: Yeah, absolutely. (06:07):
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It did. And it's the same idea here.
These two stars orbit in a period of about17 days, and the change in the magnitude is
relatively small, about 0.10.

Jordan: Yeah. I imagine you're going to need a telescope to see that kind of change. (06:19):
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Kit: Oh, yeah. Unless you've got superhuman sight. (06:23):
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Jordan: Well, considering how well we did with Percy Jackson and the Olympians, I'm not. (06:26):
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I'm not liking our chances.

Kit: No. There is some evidence that this system has a planetary or proto planetary system, (06:33):
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because there seems to be a dust cloud ofsome kind around the system, but we don't
have any confirmed planets yet.
And the final tidbit that I learned aboutthis star is that it is one of the 15
Behenian fixed stars, which were stars thatwere considered special and magical and

(06:58):
medieval astronomy.

Jordan: Some of the other ones that we've met this season that are also part of this magical (07:00):
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group include Algol, the Demon Star, onceagain, Beta Persei, and Vega, also known as
Alpha Lyrae.
There are also some other stars fromprevious constellations represented in this
group, including stars from some of ourearlier constellations that we covered:

(07:23):
taurus. Leo, Virgo and Capricornus.

Kit: Wow. Shout out to season one constellations. (07:28):
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So now that we know that bear is a B-minusstudent, let's move into our next segment,
Bayer's Variable Star, where we follow theGreek alphabet.
Well, one of us does, and we learn about theBayer designated stars in the night sky.

Jordan: I'd like to think I follow about 82% of the time. (07:49):
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Kit: Well, we're supposed to be on Omicron Coronae Borealis, but this was up to you, Jordan. (07:53):
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What what did we decide to do.

Jordan: Here on the last cosmic background, I wanted to ensure the integrity of Variable Star in (08:02):
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its current iteration.

Kit: Very important. (08:11):
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Jordan: Kit, i didn't want to let you down. (08:13):
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And plus, it doesn't hurt that OmicronCoronae Borealis actually does have some
interesting stuff going on.
Unlike the last time I had to deviate from Nu Lyra.

Kit: Oh, poor Nu Lyra trying its best. (08:27):
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You know, not all stars can be special.
Some of them are just regular stars, likeour sun.

Jordan: Omicron Coronae Borealis is a K-type giant star. (08:34):
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It's off that main sequence, and it'sactually designated as what's called a red
clump star.

Kit: No, nope, I don't I don't care for that. (08:47):
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I don't care for that astronomical term.

Jordan: No. Basically these red clump stars, though, Kit. (08:52):
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Their red giants that are a little bithotter than other red giants.
They're red giants that got redder.

Kit: I just why couldn't we just call them hot red giants like that to me, that's better. (09:05):
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You know, if I was in charge, if I was theJohann Bayer of our times, I'd call them hot
red giants or better yet, red hot giants.

Jordan: Kit, I prefer clump stars. (09:21):
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You are more than free to start a petition.
Omicron Coronae Borealis has an apparentmagnitude of positive 5.53.
Not very bright.
And it's located 270 light years from Earth,so pretty far away.

(09:45):
And it's actually moving closer to us ratherthan further.

Kit: Red `clump attack. (09:50):
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Jordan: The red clump star also has a confirmed exoplanet, which we love to see. (09:52):
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This one is 0.83 Jupiter masses, so it's alittle bit smaller than Jupiter and orbits
every 187 or 188 days.

Kit: Al right, so we're talking about orbit wise, sort of in the ballpark of Venus around the (10:10):
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sun, which is about 225 days.

Jordan: Precisely. And that's, well, that's all I got here on Omicron Coronae Borealis. (10:17):
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But guess what?
Stuck to the prompt.
Let's take a quick break and then we'll comeback for your Gold Star of the month pick.
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(10:45):
Welcome back.
This segment is called Gold Star.
In this segment, we alternate picking thestar or space object in our constellation of
the month that captures our mind, our heart,perhaps even our soul.
Let's find out.

(11:06):
Kit, what was your pick this month?

Kit: So Corona Borealis isn't particularly full of notable or famous deep sky objects, but there (11:09):
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were a couple of things that stood out to meas I was learning more about this
constellation. And so I have a runner up andthen I've got a pick.
So the runner up was a star called T CoronaeBorealis.

Jordan: T like like Mr. (11:32):
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T.

Kit: Yeah, just the letter T. (11:35):
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Jordan: Yeah. So what's the naming convention on that one again. (11:37):
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Because I'm not sure.
Is that Greek or.

Kit: Nope. Nope. Not Greek. (11:43):
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So variable stars are designated with theletters R through Z, and then double R, RS,
etc.. So this is a variable star which getsa different kind of designation then.

Jordan: Yeah, yeah. This this sounds familiar. (11:57):
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We have covered this before I, I apologize.

Kit: I'm very upset. (12:03):
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Okay. So T Coronae Borealis also has anickname and it is much better than its
variable star designation.
Its nickname is the Blaze Star.

Jordan: You love to hear it. (12:17):
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What a great name.
The Blaze star.

Kit: And it has that name because it is a recurrent nova. (12:21):
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Jordan: Ah, okay, so occasionally, sometimes it's blazing aka it brightens periodically. (12:26):
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Kit: Exactly. So novas are not the same thing as supernovas. (12:33):
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So supernovas are when the star basicallybrightens and then collapses and dies.
Novas, by contrast, are actually a periodicbrightening.
They're caused by a variety of differentthings.
But in this case, the Blaze star is beingcaused by the interactions in this binary

(12:56):
system. So this binary system is comprisedof a white dwarf and a cool red giant.
And the cool red giant is transferring itsstellar materials to the white dwarf.
And the white dwarf, as a result, has anaccretion disk around it.
And periodically just big chunks of materialare transferred in the luminosity of that

(13:17):
white dwarf brightens, and then it kind ofsimmers back down.
But the star is still intact.
It hasn't exploded and collapsed.
It's just periodically brightening becauseof this interaction.

Jordan: If I was to explain it like I was five, I would say White Dwarf gets a big meal and is (13:30):
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happy.

Kit: Right. Yeah. Pretty much. (13:36):
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Jordan: Sounds great to me. (13:37):
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Kit: So we have a record of this particular recurrent nova since as early as 1886, when (13:40):
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it was observed by John Birmingham.
John Birmingham lived between 1816 and 1884,and he was an Irish astronomer and also a
polymath, poet and amateur geologist, and hewas also fluent in several languages.

Jordan: Dang doing it all John Birmingham. (14:05):
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Kit: We also have some historical records suggesting that this nova was also observed (14:09):
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in 1217 and in 1787, but those ones aren'tnecessarily confirmed as the blaze star.
That said, we do have confirmation of thisstar blazing in 1938, 1946 and 2015 and

(14:32):
there was a recent release back in June ofthis year of 2024 from NASA, saying that
they're expecting the blaze star to brightensometime very soon.
It dimmed noticeably in March 2023.
And so they're saying like, keep a lookoutbecause this is coming probably this year,
but certainly within the next two years.

Jordan: Okay. If I was lucky enough to plan this right, what kind of apparent magnitude swing (14:53):
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would I be on the lookout for?
Like, what are we talking about in terms ofthis nova, Kit?

Kit: So it seems to vary quite a bit. (15:03):
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Usually this star, which is actually twostars, has an apparent magnitude of 10.5.
So positive 10.5, but it's increased to 9.2,which is not very much.
But we've also seen an increase to positive2.5.

(15:23):
So when it does blaze we might be able tosee it or it might be one of these smaller
blazes. It kind of depends on how much it'seaten from that red giant.

Jordan: That makes sense. It's dependent on the amount of material being transferred, i.e. (15:33):
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eaten between the stars.
So it's not going to be predictable ornecessarily as large as other kinds of novae.
And we'll find out.

Kit: Yeah, it's kind of exciting. (15:46):
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It happens about every 80 years or so theyestimate with the blaze star.
So it's kind of cool that we'll get to seeit.
So obviously the blaze star has an amazingname and is cool.
But my gold star actually this month goes toAbell 2141, which is an ongoing merger of two

(16:08):
galaxy clusters.

Jordan: I can't even wrap my head around this. (16:10):
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Tell me more.

Kit: Yeah, so we're talking clusters of galaxies. (16:12):
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So the Milky Way is an example of a galaxy,right?
But we're in a group of galaxies.
So these are groups of galaxies heldtogether by gravity.
And these two clusters of galaxies aremerging.
So we're talking about hundreds of galaxies.

(16:32):
Lots and lots and lots of gas and anobject, when we're thinking about these two
clusters together, that's about 6 millionlight years across.

Jordan: So we know the entire Milky Way galaxy is approximately 100,000 light years--a (16:41):
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mid-sized galaxy.
So to go from 100,000 to 6 million, I mean,this is like hard to imagine.

Kit: It's huge and it's massive. (16:58):
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And we actually know quite a lot about thiscollision from the Chandra X-ray Observatory,
which has showed actually different pressurefronts and temperature readings, which
actually sort of means that this collisionhas a weather system, not like we know it,
but sort of that same idea of like...

Jordan: It's a complex, chaotic system that's playing out. (17:19):
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But yeah, how far away is this going to be?
Like, what kind of things do I have to worryabout?

Kit: All right, well it's moving away from us. (17:28):
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So that's the first good news.

Jordan: Great. (17:32):
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Kit: And the second good news is that it's 1.2 billion light years away. (17:33):
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So nothing to worry about.
A lot to learn, lots of science to do andthink about.
And there's actually a really cool tour ofthis merger from the Chandra X-ray
Observatory, and I'll definitely post thaton the socials, because it is very cool, and
it's even cooler knowing that it's very faraway from us.

Jordan: What an excellent addition to the Gold Star of the month club. (17:55):
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Abell 2141.
Best of luck to both galaxy clusters in yourfuture union.
[music] This brings us to the end of ourexploration

(18:17):
of the cosmic background of theconstellation Corona Borealis.
Next week we will be retelling andretconstellationing the myths of this
constellation.

Kit: This has been Kit. (18:29):
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Jordan: And Jordan. (18:31):
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Kit: Sisters, lovers of stars and stories. (18:32):
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Jordan: And we'll see you next time. (18:34):
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Kit: On Starry Time. (Transcribed by Sonix.ai - Remove this message by upgrading your Sonix account) (18:36):
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