Caoimhín's Content

Firstly, this video has a terrible visual artifact around the webcam. I believe I know what went wrong and should be able to prevent it in future videos, but I’d rather post something than skip a week, so here we are.

I have updated the version of Stellarium that I am using. Up until recently, I was using Stellarium 0.21, and being a few updates behind isn’t too bad. Nothing major is changing in space, new updates mostly bring new features to Stellarium, sometimes new information such as updated names, but it’s not like we’re going to get a new Moon or anything. However, in a recent video all about asteroids, Stellarium informed me that the orbital characteristics may be out of date. So in this video, we take a quick look at Vesta to show that it is still in the location it appeared to be previously, so thankfully no retractions needed there.

The new update, Stellarium 0.23 seems to make the user interface a little larger, so hopefully the little sliders and checkboxes I use to change the display will be a little more legible to you as well. One part of the update is that slightly newer names are now available for a particularly interesting group of objects, the exoplanets. Exoplanets have been known now for a few decades, planets orbiting other stars, and Stellarium has provided the option to highlight them in the sky for a few years, just like it labels planets and deep sky objects. Generally, Stellarium labels what is visible in the sky, and so with exoplanets a label will appear if the star is visible or nearly so.

You’ll notice immediately, that there is a smattering of labeled objects, even in light polluted city skies. Such bright and famous stars as Aldebaran and Pollux have planets orbiting around them, stars you can see with your naked eye. Just next to the North Star, in Ursa Minor, the star Beta Ursa Minoris has a planet orbiting it. Stars that we can see with the naked eye are often named after there constellation if they don’t have a more famous name. The brightest star is alpha, and alpha Ursa Minoris exists, we just normally call it Polaris or the North Star. The second brightest star is beta, and in this case it doesn’t have a famous common name. However, it is a star that is always visible to us here in Ireland thanks to its position in the sky. As long as it’s not cloudy, you can see the Sun of a distant solar system with your own eyes any time of the year from most parts of the northern hemisphere.

Most of the exoplanets we’ve discovered orbit stars that we don’t see with our naked eyes, and detecting an exoplanet to begin with requires a camera, particularly one that can measure the amount of light coming from a star over time and track any changes. There are a few ways to detect a planet around another star, very big planets will make their stars wobble from side to side, but the transit method is the one I’ll briefly explain here. If a planet passes between us and a star, it will block some of the stars light. We don’t usually see the star blink out completely, this is rarely an eclipse, just a slight dip in the stars light. This is why sensitive equipment is necessary to see the subtle changes. If these dips happen regularly, then we can measure the length of the planets year and work out how far from the star it is. By measuring how much light is blocked out, we can get an idea of the planets size, and eventually other characteristics as well, like the expected mass and surface gravity.

Many telescopes have been purpose built to find planets, and the Kepler Space Telescope was one of them. Kepler observed one patch of the sky for years, measuring the light curves of the stars that it could see. Human researchers analysed this data, and saw the dips in light that indicate planets. I tend to say that Kepler (the telescope, named after an astronomer) discovered thousands of planets, but really it just allowed people to discover the planets, telescopes, even with fancy cameras and software built in, are still just tools for us to use. Many of the stars Kepler saw planets around didn’t have popular names, and so they were named after Kepler using numbers. Kepler-1, Kepler-2 and so forth. This same process is used with other telescopes, and so we end up with a lot of repetitive, boring names.

The International Astronomical Union is the body in charge of categorizing and naming objects in space. They are an international group with over 100 member countries. A decision was made to give at least a few of the thousands of new planets and stars names, names more similar to the famous stars we can see like Pollux and Aldebaran. To ensure that these names weren’t too heavily biased towards any one language, the duty of naming various stars and planets was spread out to different countries, one system to each member state, with the instruction to use native languages and make reference to things of cultural significance.

This process has produced some wonderful systems. These include mu Area being renamed Cervantes after the Spanish author, with it’s planets being Quixote, Dulcinea, Rocinante and Sancho after characters from Cervantes’ book “Don Quixote”. These would have been mu Area a, mu Area b, mu Area c and mu Area d otherwise. This was part of the first small campaign in 2015, where just 14 stars and 31 exoplanets were named. A much larger campaign, the IAU100 NameExoWorlds campaign, in celebration of the 100th anniversary of the IAU in 2019 is when Ireland got a planet.

The star HAT-P36 was discovered to have a planet, called HAT-P-36b by its discoverers. This system was discovered using the High Altitude Telescope, just one of many fun acronyms astronomers user, such as MASCARA, the Multi-site All-Sky CAmeRA, and TRAPPIST, the Transiting Planets and Planetesimals Small Telescope. This system is the one given to Ireland to name, and lying in the constellation Canes Venatici, it’s “visible” all year round for us, just not with the naked eye. In fairness, it’s pretty faint even with a telescope. There were many proposed names for this system, but the finally selected ones were Tuiren for the star and Bran for the planet.

The names Tuiren and Bran come from an old Irish story, and I don’t want to repeat too much of what I said in the last post, but suffice it to say that thanks to an unfortunate run in with an evil fairy, Tuiren was turned into a dog and bore two puppies, Bran and Sceolán. Being in the constellation of the Hunting Dogs, it’s an appropriate myth to use, and gives a great opportunity to show off some Irish names in the sky.

The IAU had another naming campaign in 2022, so I look forward to investigating some of these names, perhaps even in a future video about the renamed stars and planets more generally. Of course with the New Year coming up, that is likely to be the focus for the next few posts I make, and I hope you stop by to give them a watch and a read.