Our Sun is a single star, but it still has siblings in the sky. The stars form in the clouds. The stars would have formed from the same cloud when the Sun formed.
There were other stars in the cluster.
Two atoms of hydrogen bond together in a cloud called amolecular cloud. Hydrogen is the main component.
Astronomers can see a lot of clouds in space and use telescopes to peer into them. The closest cloud to Earth is the Molecular Taurus Cloud. One or two million years old, the stars in the Taurus GMC are only one or two million years old. A lot of young stars are in the nursery.
When a cloud collapses to form stars, dense cores are formed where gas accumulates and draws more gas into them. The core becomes a star of different types. Some of the Sun's siblings will live a long time before exploding as supernovae. This is important.
A star cluster was formed by the Sun and other stars. The cluster was broken up due to the interference of other clouds. The stars are called stellar associations when they move in the same direction in space. Astronomers found the Sun's first sibling in a paper published in 2004. It is about 120 light years away. The researchers were able to identify it using its chemical metallicity.
Each of the Sun's hundreds or thousands of siblings would have formed in its own core in the cloud. Two researchers from Japan tried to figure out how many siblings the Sun has.
The study is titled "On the Number of Stars in the Sun's Birth Cluster" and it has been submitted to the journal Astronomy and Astrophysics. Sota Arakawa is one of the authors. Both Arakawa and Eiichiro are from the Japan Agency for Marine-Earth Science and Technology.
Carbonaceous chondrites are the most primitive meteorites. There are tiny rocks called CaIs. Scientists use CAIs to date our solar system because they are the oldest dated solid objects. The age we use for the solar system is based on their weighted mean age.
26 Al is a metal that can be found in CAIs. 26 Al is a radioactive isotope. It will last 770,000 years. There are processes in the universe that can produce it. 26 Al is one of the heavy elements that can be produced through the process of detonation. They make it in the Universe.
The 26 Al in space decays into a particle. The rays from 26 Al can be measured by the astronomer. An understanding of how many supernovae there are and how often they occur is possible with the help of thegamma rays. There is a link between stars that explode as core-collapse supernovae and CAIs.
The amount of 26 Al in a meteorite can be compared with the amount of decay-related elements in the CAI to find the age of the meteorite. Poor and rich co-exist.
In the first 10 years of the solar system, a direct injection of 26 Al-rich materials from a nearby core-collapse supernova is expected. The authors say that at least one core-collapse supernova should happen within the Sun's birth cluster.
The stars form in a cloud. Young stars use up most of the gas before they start shining. The period of star formation in the birth cluster is finite, and we know the rate of supernova explosions, so we can combine them to illuminate how many siblings the Sun has. It is if that sounds complex. It is well- understood science.
The number of stars in the birth cluster can be much larger than previously thought.
The stars that die as core-collapse supernovas don't live as long as the Sun. They can form, explode, and die if they last a few million years. They inject nearby solar systems with radionuclide when they explode. 26 Al are taken up in CAI formation.
The birth of the Solar System is thought to be the location of a CCSN. It's plausible since star birth is triggered by shock waves that come from the explosion. There needs to be at least one more CCSN during the period of star formation. The event rate they came up with was for CCSNs.
There are two different scenarios for 26 Al to be injected. It can be injected into a core in the cloud where a star is forming. It could be injected into a disk around a young star. When a CCSN injects it into a core, the CCSN is the event that starts the formation of a star. A Class II young stellar object is the star central to the disk when it is injected.
The injection efficiency is dependent on the size of the dust particles. The structural evolution of the disk would be impacted by the impact of the CCSN.
There is evidence that a CCSN injected 26 Al into the circumstellar disk while the Sun was a YSO. The Sun's equator and the ecliptic could be caused by a CCSN.
Where do we go from here? There is a lot of detail. Is it possible that the Sun has many siblings? It does limit the number.
The Sun's family size has been determined in a number of previous studies. A study done in 2010 looked at how many stars there would have to be in a cluster in order for a CCSN to form. The timing of the CCSN was not considered in the study. They were not moving much. During the star formation period, the existence of massive stars large enough to become CCSNs doesn't support one.
The earlier ones were refined. They looked at the number of stars in the Sun's birth cluster from the perspective of a CCSN. The timing is constrained by that. They calculated the probability of acquiring at least one CCSN in the birth cluster.
The number of stars in the cluster is higher than previously thought. The star formation period is less than 10 million years.
Previous estimates have landed at about 500 siblings for the Sun. But this work comes in an order of magnitude higher. “The plausible number of stars in the Sun’s birth cluster would be Ncl > 2 × 103 when tSF < 12 Myr,” the authors write. “Moreover, the plausible number would be Ncl > 2 × 104 when a much shorter timescale of tSF <5>
There could be up to 20,000 siblings.
The number of siblings the Sun has is constrained by this study. It doesn't identify any of them. Calculating the size of the Sun's family can be done with the help of a survey of stars. They are going in that direction.
There are only two types of clusters for the Sun to form in. Tens of thousands to millions of stars are contained in goblets. They are still bound by nature. There are as few as a few hundred stars in an open cluster. They are only bound by the clouds and are not fully grown. They only last a short time.
There are likely many more open clusters in the sky. The stars separated from one another before the open cluster was formed.
Each cloud has a slightly different chemical mixture and the stars in it have the same chemical fingerprints. Even if they are separated by tens of light-years or more, the stars have the same fingerprints. That isn't enough, that's not enough.
There is an ambitious mission being carried out by the Gaia spaceship. The positions, distances, and motions of more than one billion stars were mapped. The biggest and most precise 3D catalog of the Milky Way has been created by those measurements. There is a huge amount of data inside the Sun.
The data shows a star's movement over the course of six months. The movement can be traced back in time to see if it is in line with the sun. It is possible that it formed in the same cluster with the Sun if it does.
The families in the Milky Way are stretched out into strange shapes.
There is still more to be done by Gaia. It has been going for 9 years. Three sets of data have been released by the mission, which has made it easier to understand the universe.
We may be able to identify the Sun's sibling group one day, thanks to the missions that follow it.
All Rights Reserved © 2024
