Caoimhín's Content

I am going to start with potentially a little bit of bad news. It’s not very bad news, but at the same time it’s not great, I am certainly a little disappointed. It no longer looks like we will see a new star in the sky this year. For a while, it seemed likely that a very faint star in Corona Borealis would suddenly brighten, becoming visible in the sky. Unfortunately, it now no longer looks like this future nova is imminent.

Just after sunset, taking a look over here into the southwest will point you in the right direction. From the city it can be hard to tell, with so much and light pollution, which stars are exactly the ones you are looking for. Thankfully, there are some a few bright and distinctive stars that can help. One way to find Corona Borealis is to look in between the stars Vega and Arcturus for the bright star Alphecca. You can find Vega at the top right corner of the summer triangle. Arcturus is just above the sunset, but if you are struggling to find Arcturus then you can start at the Plough or the Big Dipper. Follow the handle of The Plough, and extend the arc, that will bring you to Arcturus. Make a line between those two bright stars, and there will be a fainter, but still easy to see with some light pollution, star between them. This is Alphecca, the brightest star in Corona Borealis. It’s not exactly in the middle, but it is the brightest close to the middle of that line, a bit closer to Arcturus. Once you’ve found the brightest star, if the other stars in Corona Borealis are visible, the curved shape of the full constellation is reasonably recognizable.

With software like Stellarium, you can bring up the lines of the constellations. Towards the West, up above comet 2023 A3 in mid October, there is the shape of Corona Borealis, where we were expecting to see a nova last month. For a long time the dimming of a particular star in the constellation Corona Borealis indicated that that star was going to go nova. This nova is a type of recurrent nova, where the star regularly increases in brightness and then fades away again without destroying itself. Other than Alphecca, most of the stars in Corona Borealis are quite faint, faint enough to be invisible from cities with light pollution. Shifting our view out to the countryside will make things a lot easier to see. As would be expected, even for one of the fainter constellations, the shape of Corona Borealis is clear to the naked eye. Also, from the countryside the tail on comet 2023 A3 should be visible to the naked eye as well. The curved shape may not look exactly like a crown, as the name Corona Borealis, the Northern Crown, implies, but it is at least a distinct shape.

The brightest star in Corona Borealis, Alphecca, is nearly the bottom of the curve, a little to the right. This makes the portion to the left longer, swooping into a distinct curve or elbow. Just outside of this elbow or corner, is the currently very faint star that will, eventually, go nova. It’s very difficult to find this particular star, as it is very faint, but thanks to its behavior it does have a popular name, the Blaze Star. It is invisible if you’re just using your naked eye when it’s not blazing, the Blaze Star is only particularly bright when it’s blazing. It does of course have a more technical name, T Coronae Borealis, but Blaze Star certainly sounds more impressive.

The Blaze Star is a double star, and the pairing of two stars is a big part of it’s repeating variation in brightness. This is a star that goes supernova regularly, roughly every 80 years. It has been documented flaring at least in 1866 and 1946. Despite being closer to 78 years, it was predicted that this roughly every 80 year thing was going occur this year. It was narrowed down to around this September, because of the dimming of the star. The star’s dimming was thought to be a cloud of material building up around the explosive little star from its larger companion. Once enough of that extra material builds up, there’s enough new mass for fusion to reoccur, leading to an explosive fusion reaction. This is what allows the brightness to increase, and the small star can pull more new mass off of its larger companion and build back up to a flash again.

It is still a star that’s going to go nova. It goes nova regularly, it hasn’t gone nova yet, so it will go nova in the near future, we’re just not exactly sure when. It may happen by the end of October, but it also may not happen till 2026. We know it’s coming up but it’s often difficult to predict these things. Many things can be tricky to predict accurately, and novae especially when they only occur occasionally, they can be tricky. Predicting comets can be tricky as well, as I have alluded to in previous pieces. Besides the comet 2023 A3, there is another comet that we’re seeing at the moment. Comet 2024 S1 ATLAS isn’t particularly easy to see from Ireland. We may not be able to see it from here at all, and I did go over this comet in a lot more detail in a previous piece, but one of the interesting things about it is relevant again. The comet S1 is going to get incredibly close to the Sun as it passes by, and it will be coming around the Sun in late October, so we’re looking into the future here. That comet will make its closest approach to the Sun in the near future and for sungrazer comets, if they get too close to the Sun, they break apart.

Currently, astronomers are predicting this incredibly bright comet as it comes close to the Sun, and even a day or two later it could still be quite visible in the sky. However, it may also break up, it may completely fall apart as it gets around the Sun. Regardless, it’s not going to be really visible from here in Ireland anyway, but after its closest approach to the Sun or even a little before its closest approach to the Sun, that comet may just break up. That is one of the things that’s difficult to predict in astronomy, our understanding of comets to still quite minimal. We only know so much about them because we normally only get to see them from reasonably far away, or as they fly past. We have now, thanks to the European Space Agency Rosetta Mission, landed on a comet. Samples have also been taken from the tails of comets, but just looking at a comet it’s difficult to tell its composition and it’s difficult to tell how solid it is. You very rarely see comets with other objects orbiting around them, so figuring out their exact density can be difficult, and looser comets can be ripped apart by the Sun a little bit easier. Comet 2023 A3 has already come around the Sun, so we know it’s ok, in the case of comet 2024 S1, we can’t be so sure. Various predictions of this nature can be difficult, as many things aren’t guaranteed until they happen, even if they seem likely.

The Blaze Star, it will go supernova in the near future, we’re just not exactly sure when. Some astronomers were quite confident that it was going to go nova and they had a good reason, it was after dimming in the same way that it had done the last time it went nova. We should get to see a seemingly new star in Corona Borealis in the near future, so do keep an eye on it. Just because the supernova didn’t happen when it was predicted or just because it looks like it’s less likely to happen, doesn’t mean it won’t. We could be wrong again the same way that we were wrong in saying that this star was going to go nova in September. That was incorrect, it didn’t happen, we’re still waiting for it. Even though it now looks like it’s probably not going to happen for another couple of months, it could still happen tomorrow. In truth we still don’t really know, and that is an important thing about astronomy, sometimes we just don’t know, there are things that are difficult to predict, we occasionally get surprised by stuff. Speaking of surprises , there are a couple of meteor showers coming up in October, particularly the Orionids.

The Orionids are generally quite a good meteor shower, but it is hard to predict exactly how good they’re going to be, and of course it’s tough to predict if the weather will be good enough for you to easily see them. Across a few dates, even earlier in October, there has been a few meteor showers going on. Moving later in October different ones will pop up. The Orionids are there for quite a while, with a potential maximum ZHR of 20. It’s not a very high rate, but it’s not too bad. The night they peak, unfortunately, is very close to the night of the Full Moon, so that is going to interfere with our ability to see things in the sky. The Leonids coming up next month are often a very impressive shower, they can be among the most impressive. It doesn’t look like the Leonids this year are going to be crazy, like they have been in the past, with thousands of meteors in the sky. However, as I said, it is important to remember in astronomy that sometimes we don’t know,. Predicting things like the behavior of comets, the rate of meteor showers and the exact timing of novae, these are some of the things where sometimes we’re only guessing. Even with a 95% confidence interval and there’s still that 5% where something could go wrong or some mistake could have been made.

Hopefully we’ll get to see a nova very soon. Hopefully the Orionids are going to be great and the Leonids will be fantastic. Hopefully comet 2024 S1 will come around the Sun in one piece and give people a chance to see it. I hope all of those things happen, and I hope you enjoyed this piece about them. If you did, then I hope that you like it and consider subscribing to this website and my YouTube channel as well. Hopefully, I’ll see you back here next time.