Astronomy Now Online
Home Magazine Sky Chart Resources Store


Spaceflight Now +



Subscribe to Spaceflight Now Plus for access to our extensive video collections!
How do I sign up?
Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.

 Play

STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.

 Play

STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.

 Play

Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

Become a subscriber
More video



NAM Banner
Badly behaved spinning stars make astronomers dizzy
BY KEITH COOPER
ASTRONOMY NOW

Posted: April 2, 2008


Spinning stars in the Small Magellenic Cloud with the wrong levels of mixing are challenging astronomers theories about massive stars. Image: A. Nota (ESA/STScI) et al., ESA, NASA.

Fast spinning, massive stars have shown that the way in which gases are mixed inside them isn't as simple as had been assumed, according to a new study involving the Very Large Telescope at the European Southern Observatory in Chile, and presented at the RAS National Astronomy Meeting at Queen's University in Belfast.

Massive stars rotate very quickly, although nobody is sure why. Because massive stars only exist for a few dozen million years before exploding as supernovae, compared to billions of years for lower mass stars like the Sun, astronomers do not know whether the fast rotation is down to their mass or whether it is down to their young age. Regardless, the fast rotation creates powerful, spinning currents inside the massive stars that churns up the gases within them, a process termed 'mixing'. However, the new study conducted by astronomers at Queen's University has found that this is not necessarily the case.
VIDEO Professor Stephen Smartt of Queen's University in Belfast speaks with Astronomy Now Editor Keith Cooper about his team's research into the chemical composition of massive, rapidly spinning stars.
  PLAY

Spending 112 hours in total using the FLAMES multi-object spectrograph on the Very Large Telescope, which can measure spectra from 132 different objects simultaneously, they targeted 800 massive stars found in star clusters in the Large and Small Magellanic Clouds, and the Milky Way. To measure the amount of mixing, they studied the amount of churned up nitrogen that had made its way to the surfaces of these stars. The clusters were divided up into ages of one to five million years, and 10 to 15 million years, to compare the different stages of their evolution. But they found that 20 percent of the stars were relatively slow rotators yet had an overabundance of nitrogen at their surfaces, whereas another 20 percent were fast rotators but had less nitrogen amongst their surface composition. Additionally, they found that stars in the Small Magellanic Cloud span faster than their counterparts in the Milky Way that have a similar composition. The remaining sixty percent appeared to fit previously established models, but the badly behaving forty percent suggest that other factors other than spin rate are at work in the mixing of material inside a massive star, which could affect how they evolve in terms of their lifetimes and specific type of supernova when they die.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
 GET YOUR COPY

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
 GET YOUR COPY

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
 GET YOUR COPY


HOME | NEWS ARCHIVE | MAGAZINE | SOLAR SYSTEM | SKY CHART | RESOURCES | STORE | SPACEFLIGHT NOW

© 2014 Pole Star Publications Ltd.