The KELT-9b planet was found using one of the two telescopes called KELT, or Kilodegree Extremely Little Telescope. Posted by Danny Shook at July 18, 2020. If the Sun was a hypergiant star, it would reach out to as far as Jupiter. Now, we don't know what all can happen in the greater universe. Jupiter is about as big as a planet can be without becoming a star. No, not possible. They are no bigger than a city. Earth is about the size of an average sunspot! One of the smallest known red dwarfs is EBLM J0555-57Ab, which is smaller than Jupiter. A Jupiter mass planet could easily orbit a star of that size, in the sense that Jupiter orbits our sun. It would likely not disappear, due to the gravitational lensing of the light. Researchers say that a space rock that landed in Costa Rica on April 23rd, 2019, came from an asteroid that exists as a I've read that it is possible for a planet to be bigger than a star, but is it possible for a planet to be bigger than the star it orbits? Example: Of course these stars are far more massive than any planet, but OP asked about size, not mass. So I'm just wanting to know, is it theoretically possible for an extremely huge exoplanet to be larger than its extremely small host star? So far, they are just theoretical objects. I think OP was asking if a planet can possibly be large enough to be larger than its main sequence star as a matter of happenstance, rather than if its possible for stellar remnants to be smaller than the orbiting planets. A smaller body always orbits around a larger body rather than the other way around because the larger body has more gravity. Favourite answer. This main sequence star is the size of Saturn. What is the biggest planet we know of? Planets are typically brighter than stars. It is a Jupiter sized planet orbiting a roughly Earth-sized white dwarf! He asked if an "extremely huge" planet can be large enough to be bigger than its star, which can't happen. ... Scientists hope to use 3D modeling in the future to understand how a rocky planet around a dim star could fare as well. It orbits its star in only about 10 Earth-days. Rules: https://www.reddit.com/r/askastronomy/about/rules However, not all of the moons are smaller than all of the planets. The most recent definition of a planet was adopted by the International Astronomical Union in 2006. Some scientists are calling this object a planet. The reason for differing brightness is because starts reflect the light of the sun, which is close to the planets, while the stars emit their own light. I want to build a planet (or satellite) that: is smaller than Earth, has a thicker atmosphere than Earth but breathable, has neither intense volcanism, nor any extreme condition of that sort that would increase atmosphere density, revolves around a binary star similar to BY Draconis; A higher gravity makes for a higher atmosphere density. Don't know. The Goldilocks Zone is often referenced (an area around a planet’s host star which could be ‘just right’ for liquid water to exist) when it comes to habitability. The smallest planet in the solar system is Mercury which has a diameter of about 3,032 miles. Make this planet too big and you risk losing ozone. Moons are always smaller than the planet that they orbit (move around). But we don't even need to consider them, because red dwarfs can be smaller than Jupiter. A star is what planets orbit around. You might be able to with a red dwarf but it would be a very low mass one with a planet the size of Jupiter or larger. Neutron stars however would be fairly easy to block out, even a large asteroid(>10 km) could completely cover it. I would disagree with this as you are talking about a white dwarf which is a stellar remnant rather than what we typically call a star. Yes, in fact the first confirmed extrasolar planet is bigger than its star: The planet PSR B1257+12b has a radius of at least 7500km, and its star PSR B1257+12 (which … What is bigger than the Sun and all the planets yet lighter than air? save. Yes, the largest exoplanets are larger than the smallest stars. what about planets arround a pulsar? We know that these kinds of circumstances exist, but we have yet to observe such an instance where the two reside in the same system together in nature, and that’s one of the biggest challenges behind answering this age-long question. Exoplanet Habitable Zone Around Sunlike Stars Bigger Than Thought. Can a planet be bigger than its star? yet, both stars and planets have different sizes, such as a white dwarf star is smaller than Jupiter. This suggests main sequence stars may be smaller in radius than gas giants, but this doesn't mean tiny stars will have gas giants orbiting them. As the star is a white dwarf it didn't start out this way, the star would have been larger than the planet, but when it ended it's main sequence lifetime the star would have swelled into a giant, swallowing the planet. Of course, as a main sequence star (not a brown dwarf), it has to be a lot more massive than Jupiter. https://en.wikipedia.org/wiki/EBLM_J0555-57#EBLM_J0555-57Ab. but if it is stellar remnant, then you got it. Jupiter’s pretty big, but it’s actually only about 1/1000th the mass of our star. As I recall, above a certain size, planets get smaller with increasing mass because the pressure at their core gets great enough to compress the hydrogen enough to make that possible. In terms of mass, neutron or white dwarf stars could be packing ten solar masses’ worth of matter into a blob about the size of a metropolitan city. It might seem to disappear, but some light in a corona shape, would still be technically heading towards us. These two stars constitute a BY Draconis variable. It is actually possible (although unlikely) for a planet to be hotter than other stars as long as the star it orbits around is even hotter. Regarding shape, stars appear as a dot while planets appear spherical. So it's a little odd to think of a planet being bigger than a star, but we're not talking about a normal star here. Press J to jump to the feed. On the other hand, because KELT-9b's host star is bigger and hotter than the sun, it complements those efforts and provides a kind of touchstone for understanding how planetary systems form around hot, massive stars," Gaudi said. 6 months ago. Generally, stars are also bigger than planets. Similar stories can be told about exoplanets residing in other stellar systems, where those stars can be hundreds of times larger than our Sun. Any planet orbiting component A or B would not be conducive to life. See /r/telescopes! Therefore no planet could ever be remotely close to the same mass as the sun. It must be big enough to have enough gravity to force it into a spherical shape. That extra energy source tends to increase the radius, at least for a little while. 6 Answers. Would it be torn apart by the tidal forces? The Very Large Telescope (VLT) of the European Southern Observatory (ESO), an array of four individual telescopes in the Related: Everything you need to know about exoplanets. Stellar remnants like white dwarves, neutron stars, etc are a different story—they are post-star objects that started out much larger than their planets, even if they became smaller after they ran out of fuel, went supernova, etc. If you could stand on the planet, the star would seem 60 times larger in diameter than the Sun does when we see it from Earth. It can happen. It will be quite some time before we can resolve a first generation star. But there could be some instances in which exoplanets may appear larger than the host star, such as when the host star is a neutron or white dwarf star instead of a more traditional variant like our Sun. Just one handy quote: The Sun weighs about 333,000 times as much as Earth. But, being denser, the planet could survive inside the giant star, and once the giant star became a planetary nebula + white dwarf core, the planet remained orbiting it every 1.4 days. Yes! It is possible if the star is a white dwarf or a neutron star. Jupiter is about as large a planet as you can get, and it's still only 1/10th the diameter of the Sun. Remember the difference between a Brown Wolff and a main sequence star is whether the nuclear fusion takes place in the Stars Core, which we believe … More info at it's wikipedia page: https://en.wikipedia.org/wiki/WD_1856%2B534. If a star had a planet larger than it and if that planet happened to transit its sun as seen from Earth, then yes that "transit" would actually be an eclipse and the star would completely disappear for a short time. Show me what you got... 3 comments. A planet can only get so massive before it starts fusing its own atoms together, at which point it can't get any larger, just more dense. A neutron star has a large amount of mass in a very small space. otherwise, A star(not solar remnants) will always be bigger than its planets. It could also just mean that it's not causing fusion. Cookies help us deliver our Services. Hide Caption Also, is there a size limit we can expect from planets? A star of the aforementioned variety would theoretically be suitable enough to support a solar system as large or even larger than one like our own, but due to the circumstances surrounding its size, it would visually appear smaller than a planet like Jupiter despite being more massive. ... Nebulas are vast clouds of dust and gas that are remnants of exploded stars or in other cases, nurseries for where stars The smallest star, EBLM J0555-57Ab, is 85.2 Jupiter masses and 0.84 Jupiter radius, a little bigger radius than Saturn. Stars do the reverse, because as they get larger, their energy output increases, causing a star to puff up, but this particular star is just barely massive enough to fuse protium (the most common isotope of hydrogen), so its energy output is very low. Reactions: Labels: Astrum. Somebody else already mentioned the star EBLM J0555-57Ab, which has a radius only slightly in excess of that of Saturn (and less than that of Jupiter), https://earthsky.org/space/discovery-smallest-star-eblm-j0555-57ab. As they get more massive they get denser but not bigger. John. A planet orbits a star, and only a star. The planet GU Psc b, seen in an artist's conception, is about 10 times bigger than Jupiter, and is located about 50 times farther away from its star than the dwarf planet Pluto is from the sun. (Please read our subreddit rules first!) Danny Shook “If you want to forget something or someone, never hate it, or never hate him/her. It is so large that about 1,300,000 planet Earths can fit inside of it. Since the planets are so much closer to the Earth than the stars, they appear larger to us. Planets not have a thermonuclear process. No. That's fundamentally caused by an increased fraction of interior degenerate matter in the form of liquid metallic hydrogen, which has the wacky property that the more of it you add, the smaller it gets. The planet found using TESS, WD 1856b, is about 10 times bigger than Earth (so slightly smaller than Jupiter) and orbits the star at a distance of just 3 million kilometers, which is close — Mercury's orbit around the Sun is 15 times wider — and circles the white dwarf once every 34 hours. The planet is ten times larger. So they can. Yes, a giant planet similar to Jupiter could be orbiting a neutron star (which is not much bigger than the Earth. Incredible footage shows a newly-discovered planet more than three times bigger than Earth which has been spotted orbiting the nearest single star to the Sun In fact, most objects between 0.3 Jupiter masses and 80 Jupiter masses, whether a planet, brown dwarf, or star, are roughly the same size. If we consider neturon stars as stars then yes, a planet can be larger, but the star will remain the most massive. Edit: y'all downvoting this are missing the point of OP's question. The smallest red dwarf stars are smaller than Jupiter. White dwarfs are, as the name implies, small, typically only slightly bigger than Earth. So, with this in mind, is it even possible for a planet to be larger than its host star? Can a planet be bigger than it's parent star? Some of the smallest main sequence stars out there have a radius of around 70,000 kilometers, while some of the largest known exoplanets measure almost double that. If you can't tell whether an object in the sky is a star or planet, you'll want to learn how to distinguish between the physical features of these two celestial bodies, and when it's best to view them. The white dwarf star is making the planet lose some 260 million tons of material every day. He asked if an "extremely huge" planet can be large enough to be bigger than its star, which can't happen. The Sun has about 1000 times the mass of Jupiter. Planets Jupiter-mass planets are about as large as a planet can get. Coupled with other evidence of water i The star is more than 50 times as dense as the Sun. ... For the first time, scientists have found water on the moon's sunlit surface. I didn't see anyone answer the second part of your question. WD 1856 b was discovered last year. A moon orbits a planet. Lighter gases escape easier from a given planet than do heavy gases. It will always be smaller than its star. Another tricky candidate for making this statement true are red or brown dwarf stars. Hypergiant stars are the largest stars in the Universe. Of course, that's pretty darned massive. ... Navigating beyond Earth's orbit is tricky. Volume-wise, they're much smaller than non-white dwarfs. Asteroid Sizes and Planets. Short answer is NO. This planet is thought to be at least twice as big as its star! Anthony is a technology junkie that has vast experience in computer systems and automobile mechanics, as opposite as those sound. That's why the Earth lost any primordial hydrogen and helium envelope it might have had. This illustration depicts Kepler-62e, a planet in the habitable zone of a star smaller and cooler than the sun. It is about 1,200 light-years from Earth in the constellation Lyra. The answer is, not likely. When you look at the confines of our solar system and notice just how large the Sun is when compared to Jupiter, the largest planet in the solar system, it can be difficult to conceptualize an instance where a planet could possibly be bigger than its host star. Planets are typically brighter than stars. I … Science is full of arguments like this. The center of mass between the planet and the star would, I think, be outside of the star, because the star is so very small, but the same is true of our sun and Jupiter, and the latter is still thought of as being in orbit around the Sun, because it move so much more than the Sun does. At 13 Jupiter-masses, a gas giant becomes a brown dwarf and starts up fusion of deuterium. Our planet would also be made of the wrong stuff- White dwarfs (and thus, theoretically, black dwarfs) are made of Carbon and Oxygen- most stars aren't hot enough to fuse all the way to iron. If Jupiter were much larger, pressure would be great enough to have fusion happen in its core, which is a star. share. 6 Answers. Are you confusing the idea of a star's size (its volume) with that of its mass, or are you just assuming that a more massive object has to have a larger volume? Or maybe it was created around a star and it somehow got flung off into space. They have a diameter over 1,500 times bigger than the Sun. Just one handy quote: The Sun weighs about 333,000 times as much as Earth. If the planet is made of metal (a technical term among astronomers that means anything by hydrogen or helium), it will be harder to fuse, so it can be bigger without being a star. you need a telescope to see some of the planets.a star twinkles.a planet glows. The planet is ten times larger. The Sciences This Giant Planet is 4 Times Bigger Than its Dead Star Astronomers discovered a Neptune-sized planet orbiting an Earth-sized star. Lv 7. Some moons can actually be smaller than some asteroids. It is the source of light and heat. If the star that created those elements is still there when the planet is being formed, it is fully possible that the star has a smaller radius than the planet orbiting it (like a neutron star), but the star will also be much denser than the planet, ensuring that the centre of the orbit is nearer to the star than the planet. A moon is always smaller than the planet it belongs to, but some large moons are bigger than small planets. So it can not have the same size as the stars. Sure, the planet would have to be pretty big (while staying at the same mass), but it could happen. The sun is what we call a yellow dwarf star. report . Fascinated by scientific discoveries and media, Anthony found his way here at LabRoots, where he would be able to dabble in the two. Well before that, though, cold giant planets reach their maximum radius around 3 Jupiter-masses, and start shrinking in radius as mass increases from there. Earth is about the size of an average sunspot! 75% Upvoted. Researchers have shown that it would need a reflective disc 19 times bigger than the Earth's diameter to achieve the orbital change over a timescale of one billion years. Answer Save. I don't knwo about the telescope part tho. Regarding shape, stars appear as a dot while planets appear spherical. Lv 7. While these hypothetical exoplanets could appear larger at first glance, that’s because they’d only be larger volumetrically. 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