European Association for Astronomy Education

Source: Space Daily

Artist conception of the unique binary star NLTT 11748.
Credit: Steve Howell/Pete Marenfeld/NOAO

Santa Barbara CA (SPX) May 19, 2010 Astrophysicists at UC Santa Barbara are the first scientists to identify two white dwarf stars in an eclipsing binary system, allowing for the first direct radius measurement of a rare white dwarf composed of pure helium.

The results will be published in the Astrophysical Journal Letters. These observations are the first to confirm a theory about a certain type of white dwarf star. (read more)

Source:ESO Science Release eso1007

The Fornax dwarf galaxy. Credit: ESO.

After years of successful concealment, the most primitive stars outside our Milky Way galaxy have finally been unmasked. New observations using ESO’s Very Large Telescope have been used to solve an important astrophysical puzzle concerning the oldest stars in our galactic neighbourhood — which is crucial for our understanding of the earliest stars in the Universe. (read more)

Source: University of Iowa

Image: Composite image of a large radio coronal loop superimposed on an artist’s conception of Algol, a binary star system. Credit: William Peterson.

Two University of Iowa researchers have made the first direct radio image of a coronal loop at a star, other than the sun, thereby providing scientists with information that may lead to a better understanding of how such phenomena as space weather affect the Earth. (read more)

Source: arXiv

Comparison of an LBV and the Sun. Credit: University of Florida/Meghan Kennedy.

P Cygni is a good example of an LBV, it has many interesting characteristics in its own right. It was discovered on August 8^th, 1600, when it suddenly appeared, flaring up to 3rd magnitude. Over the next hundred years it continued to fade and brighten up what allowed it to be considered as variable. Flares have also been associated to the variability of the star when it brightens.

It now seems possible that the flares may be due to the presence of a second star in orbit around P Cygni. (read more)

Related links:
Universe Today

Source: Universe Today

Eta Carinae. Credit: NASA/HST

Luminous Blue Variables (LBVs) are a rare class of extremely massive stars that teeter on the very edge of being stable. The most famous of this class of stars is the well studied Eta Carinae. Like many other LBVs, Eta Carinae is shrouded in a nebula of its own making. The instability of the star causes it to throw off large amounts of mass even during its brief main sequence lifetime. What makes these stars so unstable is an open question which has been difficult to answer do the the paucity of known LBVs. Given that the initial mass function predicts that such massive stars should be rare, this is not surprising, but identifying these stars is often made even more difficult due to the reddening caused by their nebulae

.

However, an international team working from Russia and South Africa proposes that the nebula itself may be able to help identify potential candidates of LBVs. (read more)

Original Scientific Article:

arXiv.org - Gvaramadze,V.V., Kniazev,A.Y., Fabrika, S., Sholukhova,O., L. N. Berdnikov,L.N., Cherepashchuk,A.M., Zharova,A.V. (2009). MN112: a new Galactic candidate Luminous Blue Variable, MNRAS (submitted).

Source: ESO

Artists impression of stellar evolution. Credit ESA

An extensive study made with ESO’s Very Large Telescope deepens a long-standing mystery in the study of stars similar to the Sun. Unusual year-long variations in the brightness of about one third of all Sun-like stars during the latter stages of their lives still remain unexplained. Over the past few decades, astronomers have offered many possible explanations, but the new, painstaking observations contradict them all and only deepen the mystery. The search for a suitable interpretation is on.

The release and an image are available on:
http://www.eso.org/public/outreach/press-rel/pr-2009/pr-48-09.html