Hello!! Welcome to Catapulting Planets, you’re in a gigantic cosmic factory of planetary systems, just like the Solar System. How cool right?

What do you think of creating a planet with life? Pretty cool, hum!?

But wait! It’s not that easy, for that you’ll need to several concepts of physics so you can position a planet around a star, and not just that, for it to harbor life, it’s orbit cannot be too close or too far from the star, there’s a region where the planet needs to be that we call the habitable zone. Have you ever heard of the habitable zone? No?!? Don’t panic we are going to explain…

The habitable zone it’s the special place around a star where the temperature it’s just right so life as we know can prosper, and for that we need an abundance of water in liquid form. If the planet it’s to close to the star the water evaporates otherwise if it’s to close the water freezes, therefore you need to put the planet inside that zone.

Now that you know all about habitable zones you will need one more thing...

To place planet in an orbit, moving around, the star isn’t the easiest task, to achieve this you have to adjust a few things. First, you’ll have the help of a huge super galactic cannon to launch your planets, for that you’ll have to adjust the velocity which the cannon will fire your planet and also the inclination of the cannon.

Before we start, a few more useful information about your star:

For you to have life in your star system, your star needs to be stable for a while, 3.6 billion years more precisely, we call this the Main sequence. Why so long thou? Well, because that’s how long it took to life as we know to evolve and prosper here on earth. If your star passes that period, they are old and will die soon just as a star before the main sequence are too young and emit too much dangerous radiation to have life.

Great! you’re in the right path, now about the mass of your star. The mass of your star needs to be somewhere between 0.3 times the Sun mass to 1.5 time the Sun mass, since that’s the interval needed so your star has been alive for 3.6 billion years or more, and there’s no other forces interfering with your star.

All set up, no more stalling you are more than ready to take charge of the factory. Let’s go and good luck 😊

Main sequence – 3 bi years

For life to evolve in the way we known it took around 3 billion years to evolve and establish. Main sequence it’s the period where the process of nuclear fusion of Hydrogen happens turning into Helium, this period it’s the lengthiest step and it’s when the star has balance between mass and luminosity, in this period it’s also when the star doesn’t emit particles and radiation detrimental to life. Therefore, the main sequence has to last for 3 billion years or more for a planet to develop life. To star after the main sequence, there is limited time for life (older stars), and for before the main sequence since the stars are younger and still there’s to much emission on UV radiation which is damaging for life beside residual particles of the planetary formation process, life has not yet developed.

Star Mass –

For more massive stars, bigger than 1.4 times the mass of the sun, the shorter the lifespan, that being under 3 billion years, therefore there will be not enough time to establish life as we known it.

Lesser massive stars, smaller than 0.3 times the sun mass, will have a much longer lifespan, but very narrow habitable zones that are also closer to the star. For orbits nearer the star the planet rotation is in sync with the translation due to the tidal force, with that the planet will have only one side turned to the star, like what happens to our moon, with that, one of the sides would be subjected to high temperatures, the opposite of the other side which would be at extremely low temperatures, making impossible for life to form. On these stars with lower mass there are intense activities in the chromosphere, emitting energetic particles damaging to life.

Habitable Zone:

Since earth it’s the only planet that we know for sure to sustain life in the universe, we seek life through the parameters that we know, so we look for example the presence of liquid water.

The habitable zone of a star it’s where’s possible to liquid water to be present in the planets surface. Disregarding other factors that might determine the planets temperature, like the greenhouse effect, geological processes etc. Taking in consideration only planets with similar surface and atmosphere.

Stars that are warmer have a habitable zone farther and vaster than colder stars. Taking that into consideration, it’s possible to determine the distance of the borders of the zone with the following equation, in which the distance limit is:

The distance limit and the sun limit is given in UA, in which 1UA it’s the average distance between the earth and the sun, the star luminosity is given based on star mass, which is L=m³, the luminosity is given by times the sun luminosity. The limits for the Sun and it’s luminosity are:

References:

http://www.if.ufrgs.br/fis02001/aulas/vida_ET/vet....

https://www1.univap.br/spilling/AB/Aula_8%20Zona%20de%20habitabilidade.pdf

https://www.britannica.com/science/habitable-zone

http://www.astronomynotes.com/lifezone/s2.html

https://nasasearch.nasa.gov/search?query=Habitable...

http://www.astronomynotes.com/lifezone/s2.htm

https://www.if.ufrgs.br/oei/stars/mainseq/ms_evol....

http://www.if.ufrgs.br/~fatima/ead/estrelas.htm

http://astro.if.ufrgs.br/estrelas/node5.htm

http://www.solstation.com/habitable.htm#sthash.3ce...

Our team try to envision a game where the player could achieve significant and wide knowledge of the necessary parameters to harbor life in a planet, of those parameters that we are more familiar with such as liquid water, presence of oxygen int the atmosphere and planet temperature are consider in the game, also correlating them with the stars parameters like luminosity, age of the star, it’s habitable zone, mass, etc. Our efforts are focused on provide those concepts to the player in an easy and ludic way, so they can comprehend more about their solar system and apply these to others stars with planets that we could possibly find life.