Stellar evolution tagged posts

Globular cluster M4. Credit: NOAO/AURA/NSF

Using recent advancements in Australian telescope tech, a Monash Uni team has made an unexpected discovery that a large group of stars are dying prematurely, challenging our accepted view of stellar evolution revealing that large numbers of helium burning stars are dying prematurely in the M4 globular cluster. M4 is one of the closest and brightest globular clusters, and has already been very well studied. “Globular clusters are some of the oldest objects in the Universe. Although we have some ideas for what is going on in them, every time we look carefully we find something unexpected” said Professor Lattanzio.

Researchers used a new instrument called a high efficiency and resolution multi-element spectrograph (HERMES)...

Left: Chart of nuclides and important astrophysical reactions. Right: SOHO-EIT image from 14 September 1997 showing a huge eruptive prominence in the resonance line of singly ionized helium (He II) at 304 Angstroms in the extreme ultraviolet. The material in the eruptive prominence is at temperatures of 60,000 – 80,000 K, much cooler than the surrounding corona, which is typically at temperatures above 1 million K. Credit: Image courtesy of Texas A&M Cyclotron Institute and NASA

How old is the universe? What causes a star to catastrophically explode? Answering these and other questions about stellar evolutions requires knowing the rates of the reactions involved...

Artist’s impression of the baby star TMC-1A. The star is located in the center and surrounded by a rotating gas disk. Gas is infalling to the disk from the envelope further out. Credit: Image courtesy of National Astronomical Observatory of Japan

The first direct observations delineating the gas disk around a baby star from the infalling gas envelope has been made. This finding fills an important missing piece in our understanding of the early phases of stellar evolution. The baby star TMC-1A is 450 light years away in the constellation Taurus. TMC-1A is a protostar, a star still in the process of forming. Large amounts of gas still surround TMC-1A.

Stars form in dense gas clouds. Baby stars grow by taking in the surrounding gas. In this process, gas cannot flow directly into the star...

An image of LX Cyg and its surroundings, obtained with the 80cm telescope at the University of Vienna Observatory. Credit: Stefan Uttenthaler et al./University of Vienna

A carbon star is a giant red star nearing the end of its life, with an atmosphere containing more carbon than oxygen. LX Cygni could be an interesting example of an object that is currently in the process of transitioning into a carbon star. “These observations are important to understand the chemical evolution of the universe, because most of the carbon in the universe is thought to come from stars just like LX Cygni,” Uttenthaler said.

Most of the carbon in our bodies comes from an earlier generation of stars such as LX Cygni...