In our solar system, there is only one star that we know of – the sun! Our solar system is very unique in that is only has one star. Most other solar systems have at least two stars. These are called binary systems. Some solar systems with as many as six stars have been observed by astronomers.
Two paleontologists, David Raup and Jack Sepkoski, proposed in 1984 that there may be a second sun that is close enough to us to be seen every 32 million years (but still very far away!!), called Nemesis. They think Nemesis lies beyond what is called the Oort Cloud. The Oort Cloud is a giant cloud of icy space debris and comets that surrounds the sun.
The theory put forward by Raup and Sepkoski proposed that mass extinctions like the one that killed the dinosaurs occur every 32 million years – the same period of time in which Nemesis might be able to be seen from Earth. The most common theory for why the dinosaurs died is that a huge asteroid or comet (or a number of asteroids) collided with Earth. Theories propose that Nemesis may be disturbing the comets and space debris in the Oort Cloud, which sends this debris hurtling towards Earth.
In contrast, many geologists do not believe that mass extinctions happen so periodically: there is a lot of argument over whether these theories are correct! Research performed in 2010 and 2011 shows conflicting information: one study found that there was no evidence in the crater record for Nemesis; another study found evidence in the fossil record that extinction events may be periodic, but are twice as far apart as originally proposed by Raup and Sepkoski in 1984.
Astronomers believe that if Nemesis were to exist, it would have to be a red or brown dwarf. The search for Nemesis is complicated by the fact that our current technologies cannot easily tell the difference between a red or brown dwarf and a giant star from very far away. There are also thousands of different areas that could potentially contain stars that could be Nemesis, so the search is a huge one!
In 2012, nearly 2000 brown dwarfs have been identified in areas of space near our solar system, but not one of them has been found to be inside our solar system – so none of these stars are Nemesis! Two satellites tried to conduct astronomical surveys (one in the 1980s, and one from 1997-2001) to search for Nemesis, but both failed to detect an additional star in our solar system. Then in 2011, a senior scientist at NASA argued that new infrared sky surveys that have been undertaken in more recent years would have been able to detect Nemesis if it existed – but the infrared sky surveys have found nothing.
Nobody has proven that Nemesis exists yet, so at the moment, it remains purely theoretical. For now, we can only say one thing with certainty: that our solar system is unique in that it only has one star.
FAQs
Our solar system is made up of a star, eight planets, and countless smaller bodies such as dwarf planets, asteroids, and comets. Our solar system orbits the center of the Milky Way galaxy at about 515,000 mph (828,000 kph). We're in one of the galaxy's four spiral arms.
How many stars does a solar system have? ›
Flexi Says: Our solar system has only one star, called the Sun. The Sun is one of 100 to 400 billion stars in our galaxy, the Milky Way. Our galaxy, in turn, is one of over 100 billion galaxies in the known universe.
How many planets and stars are in our solar system? ›
Solar System
| Population |
|---|
| Stars | Sun |
| Planets | Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune |
| Known dwarf planets | Ceres Orcus Pluto Haumea Quaoar Makemake Gonggong Eris Sedna more candidates... |
| Known natural satellites | 758 |
18 more rowsThe observable universe has ~ 2 trillion galaxies. each galaxy has ~ 100 billion stars. Each star has about 1.6 planets. Multiplying these gives 3.2 x 1023 planets in the observable universe.
What are the 7 stars solar system? ›
AR Cassiopeiae (AR Cas) is a variable star in the constellation of Cassiopeia. It is thought to be a member of a septuple star system, one of only two known star systems with a multiplicity of 7, the other being Nu Scorpii.
Are there 2 stars in our solar system? ›
There is only one star that has ever been observed in our solar system, but some scientists have theorized that there is a second star out beyond the Oort Cloud that only comes close enough to be observed every 32 million years.
Is there only one star in the solar system? ›
Our solar system has only one star which is the Sun. Sun is the center of the solar system.
What star has 9 planets? ›
According to a new study, HD 10180—a sunlike star in the southern constellation Hydrus—may have as many as nine orbiting planets, besting the eight official planets in our solar system.
How many planets are around each star? ›
However, based on various studies, an average of between one and two exoplanets per star seems to be the most likely answer, giving as many as 400 billion planets in our Galaxy. Read more: Could two planets share the same orbit without colliding?
How many stars are in our galaxy? ›
It is very difficult to count the number of stars in the Milky Way from our position inside the galaxy. Our best estimates tell us that the Milky Way is made up of approximately 100 billion stars. These stars form a large disk whose diameter is about 100,000 light years.
A star is a body that possesses a light that causes it to reflect the light independently. On the other hand, a planet is simply a fixed celestial body with its own orbit and spins on its own axis, yet reflects the light from an external source.
Which stars have planets? ›
The stars with the most confirmed planets are the Sun (the Solar System's star) and Kepler-90, with 8 confirmed planets each, followed by TRAPPIST-1 with 7 planets. Number of extrasolar planet discoveries per year through 2023. Colors indicate method of detection.
Can a planet have 3 stars? ›
A circumtriple planet is a celestial mass that is hypothesized to be orbiting not only a single star but three stars at the same time.
How many types of stars are there in the solar system? ›
There are seven main types of stars: O, B, A, F, G, K and M. The O stars are the bright, hot, blue stars and the M stars are the dimmer, cooler, red stars.
How many stars are in your solar system? ›
In our solar system, there is only one star that we know of – the sun! Our solar system is very unique in that is only has one star. Most other solar systems have at least two stars. These are called binary systems.
Can there be 4 stars in a solar system? ›
“About 4 percent of solar-type stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.
Can a solar system have 4 stars? ›
Multiple-star systems are called triple, ternary, or trinary if they contain 3 stars; quadruple or quaternary if they contain 4 stars; quintuple or quintenary with 5 stars; sextuple or sextenary with 6 stars; septuple or septenary with 7 stars; octuple or octenary with 8 stars.
What solar system has 6 stars? ›
The system, known as TYC 7037-89-1, consists of 3 pairs of stars known as 'eclipsing binaries' because they alternatively pass in front of each other in their orbits, from our perspective. A famous example of one such star is Thuban, which used to be Earth's Pole Star.
Is every star a Sun in a solar system? ›
Namely, every Sun is a star, but not every star is a Sun. The Sun is larger and as such a lot brighter than most stars. There are billions of Suns in our galaxy alone and as mentioned, many of the stars we see are also Suns. But many celestial objects you see when looking up are not stars.
Are there more stars or planets? ›
The Kepler spacecraft at Ball Aerospace & Technologies Corp. in Boulder, Colorado. The Kepler mission surveyed a region of the Milky Way galaxy, discovering the first Earth-size exoplanets and determining that there are more planets than stars in our galaxy.
