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I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a double day; when the primary sun sets the secondary one rises, no overla...
#1: Post edited
by
Monica Cellio
·
2020-06-17T01:15:18Z (almost 4 years ago)
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<p>I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a <a href="https://worldbuilding.stackexchange.com/q/25203/28">double day</a>; when the primary sun sets the secondary one rises, no overlap. (My second star sheds enough light to make a difference on the planet.) When the planet is on the opposite point in its orbit the primary star occludes the secondary, so it's as if there were one star, lighting-wise. I'm trying to figure out the stuff in between.</p><p><a href="https://i.stack.imgur.com/dYtez.png" rel="noreferrer"><img src="https://i.stack.imgur.com/dYtez.png" alt="drawing of system"></a></p><p>The planet orbits A at a distance of 1AU. Answers on the linked question suggest that the distance between A and B should be 10-20AU for this to be viable. The planet's orbit is meant to be viable; feel free to treat it as circular despite the drawing.</p><p>I'm having trouble working out what days look like on the planet for the points in between the two marked positions. I <em>think</em> at the halfway points it'll get overlapping days, but I don't know how long (as a ratio of the rotation period). It's probably a simple matter of geometry, but adding the rotation of the planet to the orbit is causing me problems.</p><p>What I'd really like is a chart showing the progression of the day -- time of first sunrise, second sunrise, first sunset, second sunset -- for the four main points and perhaps the four in between those (so I can understand the transitions), at the equator and at what we'll call 45deg N. Treat times as relative to star A -- noon is when A is directly overhead, regardless of where B is.)</p><p>I know we're going to need some axial tilt to make this planet <em>have</em> seasons; pick and declare any reasonable-seeming number that makes your calculations easy, or default to Earth's for the sake of comparison. I'm trying to visualize what days and nights look like on this planet; I don't have precise numbers in mind.</p><p>We're also going to need a rotation period. For the sake of the question let's assume 24 hours like on Earth. In practice, once I know what the proportions look like, I'll adjust the rotation to suit the needs of my inhabitants (because we're worldbuilders and we can <em>do</em> that :-) ).</p>
- <p>I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a <a href="https://scientific-speculation.codidact.com/questions/213937">double day</a>; when the primary sun sets the secondary one rises, no overlap. (My second star sheds enough light to make a difference on the planet.) When the planet is on the opposite point in its orbit the primary star occludes the secondary, so it's as if there were one star, lighting-wise. I'm trying to figure out the stuff in between.</p>
- <p><a href="https://i.stack.imgur.com/dYtez.png" rel="noreferrer"><img src="https://i.stack.imgur.com/dYtez.png" alt="drawing of system"></a></p>
- <p>The planet orbits A at a distance of 1AU. Answers on the linked question suggest that the distance between A and B should be 10-20AU for this to be viable. The planet's orbit is meant to be viable; feel free to treat it as circular despite the drawing.</p>
- <p>I'm having trouble working out what days look like on the planet for the points in between the two marked positions. I <em>think</em> at the halfway points it'll get overlapping days, but I don't know how long (as a ratio of the rotation period). It's probably a simple matter of geometry, but adding the rotation of the planet to the orbit is causing me problems.</p>
- <p>What I'd really like is a chart showing the progression of the day -- time of first sunrise, second sunrise, first sunset, second sunset -- for the four main points and perhaps the four in between those (so I can understand the transitions), at the equator and at what we'll call 45deg N. Treat times as relative to star A -- noon is when A is directly overhead, regardless of where B is.)</p>
- <p>I know we're going to need some axial tilt to make this planet <em>have</em> seasons; pick and declare any reasonable-seeming number that makes your calculations easy, or default to Earth's for the sake of comparison. I'm trying to visualize what days and nights look like on this planet; I don't have precise numbers in mind.</p>
- <p>We're also going to need a rotation period. For the sake of the question let's assume 24 hours like on Earth. In practice, once I know what the proportions look like, I'll adjust the rotation to suit the needs of my inhabitants (because we're worldbuilders and we can <em>do</em> that :-) ).</p>