Quadruplets in a stellar womb

February 23, 2015, Harvard-Smithsonian Center for Astrophysics
An image at radio wavelengths of a young stellar quadruplet. Astronomers have discovered four distinct gas condensations in a clumpy, filamentary gas cloud (white) surrounded by dust (blue). The locations of the condensations in this image are marked with black and red dots. The four condensations are destined to form a bound multiple star system, and one of them (the red dot) has already turned on as a protostar. Credit: Nature; Pineda

More than half of all stars are in multiple systems: binary stars, or even triplets or quadruplets, that orbit one another. No one is quite sure how or why they form, but the effects can be significant, for example influencing the character of their planets. Our Sun is uncommon in having no companion star, perhaps suggesting that its configuration of planets is equally uncommon.

There are two principal ideas about how multiple stars form: fragmentation in the early stages of birth, or the gravitational capture of a nearby star later on. Computer simulations of find that both are reasonable possibilities, and so astronomers have been trying to make observations to refine the models and the conclusions. Writing in this week's journal Nature, Alyssa Goodman and her collaborators report finding a nearby stellar nursery where quadruplets are being born. The region is in the star forming molecular cloud in the direction of the constellation of Perseus, about 825 light-years away. Scientists have known for decades about a protostar in this area, a of material that is developing into a small star about one-tenth of a solar-mass in size.

Using radio wavelength observations of dense molecular gas, ammonia in particular, the team discovered that around this protostar are several filamentary gas structures in which they detected three other condensations. The other three embryos are two to three times more massive than the main protostar, and models suggest they will become stars soon - in roughly forty thousand years. The longest dimension of the complex is only about ten thousand astronomical units (one AU is the average distance of the Earth from the Sun), and so these objects are close enough together for gravity to be the major influence in their development; velocity measurements confirm that the objects are physically associated.

It is possible – even likely - that during the stars' development their orbital motions will prompt the ejection of one or two members from the system, but for now it appears that at least one binary pair will survive for longer times. Other stellar systems need to be examined in order to see how widespread these young multiplets really are, but the new results support models in which multiple form very early in the stellar womb.

Explore further: Astronomers catch multiple-star system in first stages of formation

More information: "The formation of a quadruple star system with wide separation" Nature 518, 213–215 (12 February 2015) DOI: 10.1038/nature14166

Related Stories

Most stars are born in clusters, some leave 'home'

September 24, 2014

New modeling studies from Carnegie's Alan Boss demonstrate that most of the stars we see were formed when unstable clusters of newly formed protostars broke up. These protostars are born out of rotating clouds of dust and ...

Mismatched twin stars spotted in the delivery room

February 12, 2015

The majority of stars in our galaxy come in pairs. In particular, the most massive stars usually have a companion. These fraternal twins tend to be somewhat equal partners when it comes to mass - but not always. In a quest ...

The ages of sun-like stars

February 6, 2015

The mass of a star is perhaps its most significant feature. It determines how brightly it shines (a star ten times more massive than the Sun will, during its normal lifetime, shine about forty million times brighter than ...

Recommended for you

Making stars when the universe was half its age

January 18, 2019

The universe is about 13.8 billion years old, and its stars are arguably its most momentous handiwork. Astronomers studying the intricacies of star formation across cosmic time are trying to understand whether stars and the ...

Saturn hasn't always had rings

January 17, 2019

One of the last acts of NASA's Cassini spacecraft before its death plunge into Saturn's hydrogen and helium atmosphere was to coast between the planet and its rings and let them tug it around, essentially acting as a gravity ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

movementiseternal
Feb 23, 2015
This comment has been removed by a moderator.
AGreatWhopper
not rated yet Feb 23, 2015
Yuck!!!
AGreatWhopper
not rated yet Feb 23, 2015
This site allows hard core link spam? Need 2 let folks know about that. I guess that's English. I guess simple 4 the simple minded. Hey, genious, build yerself a rocket and demo that. PULEEEEEEEEEZE???

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.