By observing and surveying 30 cool solar-type stars in the 2.5 Billion-year-old cluster NGC 6819 an international research team has created an analytical procedure for accurately determining the ages of stars with knowledge of their masses and rotation periods.
This "gyrochronology", a neologism of co-author Sydney Barnes, has been shown to work over a wide age range, significantly improving the accuracy of stellar age determination.
"The relationship between mass, rotation rate and age of the observed stars is now defined well enough that by measuring the first two parameters, the third, the star's age, can be determined with only 10 percent uncertainty," said Barnes.
A comet is a magical sight in the heavens. Comets visible to the naked eye are a uncommon event, and sometimes they put up very suggestive shows in our skies. Those of us who have witnessed the apparition of a bright comet do not forget that experience easily.
The recent landing on comet Churyumov-Gerasimenko of the Rosetta spacecraft has made even more fascinating the observation of comets from the ground, as we got treated by close-ups of the comet surface that resemble mountainous terrains on Earth. Imagining a rock streaming in the sky, coming nearby after a long trip from the Oort cloud, and maybe returning sometimes in the future, or maybe getting lost forever, is truly remarkable.
Yesterday (8th) I took this photograph of Venus and Mercury from the grounds of Reading University.
In the photograph, Mercury is about two moon-breadths down and to the right of Venus. Over the next two days Mercury will follow the arrow relative to the much brighter Venus, moving up and closer to Venus, and then move off to the right.
For folks in the USA, you should get a slightly better view as the angles will be tilted a few degrees clockwise, and near the Equator the two planets will appear to sit directly over the brightest part of the sky where the sun is directly below the horizon.
By studying the motions of different stellar populations in the disk of the Andromeda galaxy, researchers have deduced that Andromeda has had a more violent past than our Milky Way.
The structure and internal motions of the stellar disk of a spiral galaxy hold important keys to understanding the galaxy's formation history. The Andromeda galaxy, called M31 by almost no one except the 2 percent of astronomers who like to insist on renaming and reclassifying things, is the closest spiral galaxy to the Milky Way and the largest in what is called the Local Group of galaxies in our cosmic address.
In an interstellar race against time, astronomers measured the space-time warp in the gravity of a binary star and determined the mass of a neutron star just before it vanished from view.
The researchers measured the masses of both stars in binary pulsar system J1906. The pulsar spins and emits a lighthouse-like beam of radio waves every 144 milliseconds. It orbits its companion star in a little under four hours. The mass of only a handful of double neutron stars have ever been measured, with J1906 being the youngest. It is located about 25,000 light years from Earth.
In a new ESO image of LDN 483 and its surroundings, located about 700 light-years away in the constellation of Serpens (The Serpent), some of the stars are missing.
But it's not a portent of doom, it's space pollution - gas and dust are obscuring Lynds Dark Nebula 483. LDN 483 and its dark cloud are intriguing because such clouds are the birthplaces of future stars.
How might you make a new Earth? Our Terran "test kitchen" has given us a detailed recipe, it just wasn't clear how transposable it was in other areas, the same way a recipe in Los Angeles might not work as well in Denver. Now, astronomers have found evidence that the recipe for Earth also applies to terrestrial exoplanets orbiting distant stars.
"Our solar system is not as unique as we might have thought," says lead author Courtney Dressing of the Harvard-Smithsonian Center for Astrophysics (CfA). "It looks like rocky exoplanets use the same basic ingredients."