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I have an earth-like planet orbiting one of the stars in a binary system. I have learned that, for G-class stars, if the secondary star is 100AU from the primary one, I can expect the secondary st...
#1: Post edited
by
Monica Cellio
·
2020-06-17T01:16:29Z (almost 4 years ago)
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<p>I have an earth-like planet orbiting one of the stars in a binary system. I <a href="https://worldbuilding.stackexchange.com/q/25166/28">have learned</a> that, for G-class stars, if the secondary star is 100AU from the primary one, I can expect the secondary star to have an apparent magnitude of about -17, about 40 times brighter than the earth's full moon (-13).</p><p>I'd like to increase this (that is, decrease the number and increase the light). Specifically, when the secondary star is visible but the primary is not, I'd like the facing part of the planet to have a "second day", lesser than the "primary day" but still brighter than the full moon at night. I'm imagining a light level comparable to a cloud-filled rainy day on earth -- you can definitely go out and about and see what you're doing, but you'd probably want headlights on when driving.</p><p>HDE 226868 pointed me to <a href="http://en.wikipedia.org/wiki/Gamma_Cephei" rel="noreferrer">Gamma Cephei</a>, a nearby binary system. The first star (K-class) has a planet orbiting it and the second star (M-class) is just 10 AU away from the primary. This system is apparently stable, but we don't know how habitable the planet is.</p><p>Getting two sun-like stars to 10AU apart would, <a href="http://chat.stackexchange.com/transcript/message/23921560#23921560">I understand</a>, get the second one's apparent magnitude to -22. I don't know if that's enough, too little, or more than is needed.</p><p>I'm flexible about the secondary star; if changing its class and distance would increase its apparent magnitude without frying my planet or making the whole system collapse in on itself, I'm fine with that. I want two stars shedding significant light on my planet, with the primary being sun-like.</p><p>So, what apparent magnitude is enough to give me the lighting level I'm looking for, and what is the most stable and realistic way to achieve that?</p>
- <p>I have an earth-like planet orbiting one of the stars in a binary system. I <a href="https://scientific-speculation.codidact.com/questions/213926">have learned</a> that, for G-class stars, if the secondary star is 100AU from the primary one, I can expect the secondary star to have an apparent magnitude of about -17, about 40 times brighter than the earth's full moon (-13).</p>
- <p>I'd like to increase this (that is, decrease the number and increase the light). Specifically, when the secondary star is visible but the primary is not, I'd like the facing part of the planet to have a "second day", lesser than the "primary day" but still brighter than the full moon at night. I'm imagining a light level comparable to a cloud-filled rainy day on earth -- you can definitely go out and about and see what you're doing, but you'd probably want headlights on when driving.</p>
- <p>HDE 226868 pointed me to <a href="http://en.wikipedia.org/wiki/Gamma_Cephei" rel="noreferrer">Gamma Cephei</a>, a nearby binary system. The first star (K-class) has a planet orbiting it and the second star (M-class) is just 10 AU away from the primary. This system is apparently stable, but we don't know how habitable the planet is.</p>
- <p>Getting two sun-like stars to 10AU apart would, <a href="http://chat.stackexchange.com/transcript/message/23921560#23921560">I understand</a>, get the second one's apparent magnitude to -22. I don't know if that's enough, too little, or more than is needed.</p>
- <p>I'm flexible about the secondary star; if changing its class and distance would increase its apparent magnitude without frying my planet or making the whole system collapse in on itself, I'm fine with that. I want two stars shedding significant light on my planet, with the primary being sun-like.</p>
- <p>So, what apparent magnitude is enough to give me the lighting level I'm looking for, and what is the most stable and realistic way to achieve that?</p>