The Secrets of the Sun Revealed in the Stars

We are pleased to welcome Nick Wright as our guest blogger. Nick is the lead author on a paper featured in our latest press release, about how magnetic fields are generated in stars. He is an astrophysicist working at Keele University in the UK. He completed his PhD at University College London before moving to the Smithsonian Astrophysical Observatory to study X-ray emission from both young and old stars. After almost 5 years working in the US he returned to England as a Royal Astronomical Society research fellow at the University of Hertfordshire and is now an Ernest Rutherford Fellow at Keele University. When not studying the stars or writing about them on his blog, Nick enjoys cooking, gardening and travelling.

Nick Wright
Nick Wright Credit: Nick Wright


Magnetic fields in the Sun and Sun-like stars are generated by a dynamo, a process involving the rotation of the star as well as convection, the rising and falling of hot gas in the star's interior. Understanding the magnetic dynamo of our Sun is important because it is responsible for a lot of interesting and energetic solar phenomena, some of which can have a considerable impact on our Earth and the wider Solar System. The Sun's magnetic field is responsible for sunspots on its surface, the 22-year magnetic activity cycle (the "Solar cycle"), the Solar wind that pummels planets throughout our Solar System and the ejections of large quantities of plasma – a gas composed of free electrons and free atomic nuclei – known as coronal mass ejections. This ejected material can have a serious impact on Earth, resulting in geomagnetic storms that disrupt radio transmissions, damage satellites and electrical grids, as well as harm astronauts or even people flying in airplanes at high altitudes.

Chandra Finds Evidence for Violent Stellar Merger

GRB 140903A
Gamma-ray bursts, or GRBs, are some of the most violent and energetic events in the Universe. Although these events are the most luminous explosions in the universe, a new study using NASA's Chandra X-ray Observatory, NASA's Swift satellite and other telescopes suggests that scientists may be missing a majority of these powerful cosmic detonations.

"We Got This"

Women Summit
Illustration: NASA/CXC/K.Divona


Last month, I was honored to attend an extraordinary event: the United State of Women Summit convened by the White House. Since the word "summit" means a pinnacle, this couldn’t have been more appropriate for how I viewed this day and the amazing attendees I was able to share it with.

The United State of Women Summit brought together leaders in all different professional fields – from politics to entertainment, from science to finance. The common thread among all of the participants, however, was easy to find: everyone there wanted to continue to foster and enhance the opportunities for girls and women in whatever endeavors they may choose to pursue.

Tracking Down a Stealthy Black Hole

We are pleased to welcome Bailey Tetarenko as our guest blogger. She is the lead author on a paper featured in our latest press release about a possible new population of black holes in the Galaxy. Bailey received her undergraduate degree in Astrophysics at the University of Calgary and then a master’s in Physics at the University of Alberta in 2014. She is now two years into her Ph.D. in Physics at the University of Alberta, where she is studying the black hole population of the Milky Way.

Bailey Tetarenko
From right to left Bailey Tetarenko, Dr. Arash Bahramian and Dr. Craig Heinke and Dr. Greg Sivakoff. Credit: John Ulan


For fans of black holes, we live in exciting times. Nearly all of our empirical knowledge about stellar mass black holes – that is, black holes weighing about 5 to 35 times the mass of the sun – comes from black hole X-ray binary systems. In these systems a black hole pulls in material from a nearby companion star, causing the system to become very bright in X-rays. But, recently gravitational waves have been detected from pairs of distant black holes that emit no electromagnetic radiation (a.k.a. all forms of light). And now, my team's work suggests that there are many black hole X-ray binaries in our own Milky Way that emit relatively little X-rays.

How to Hold a Dead Star in Your Hand

star in your hand
Illustration: NASA/CXC/K.DiVona

Click here to watch the recent TED talk for this feature!

Objects in space are rather far away. The Moon is our closest celestial neighbor at nearly a quarter million miles from Earth, and the nearest star, our Sun, is 93 million miles away.

These extreme distances mean that it’s usually impossible to touch real objects in space (meteorites that fall to the ground not withstanding). Advances in both astronomy and technology, however, now allow you to do the next best thing: hold a 3-D model of one based on real data.

Cassiopeia A is located about 10,000 light years from Earth. How does that compare with our local cosmic objects of the Sun and Moon? One light year equals the distance that light travels in a year, or just under 6 trillion miles (~10 trillion km). This means that Cassiopeia A is an impressive 60,000,000,000,000,000 miles (100,000,000,000,000,000 km) from Earth. But since it’s in our Milky Way, it’s in our cosmic back yard, so to speak.

The story behind such a remarkable feat starts with how astronomers study space. Unlike previous generations of sky gazers, today’s astronomers look at the Universe in many kinds of light, across the full electromagnetic spectrum. Through advanced telescopes and detectors, scientists can “see” from radio waves to gamma rays. Why is this important? We need to look at the Universe in all the types of lights to even begin to understand it.

Take X-rays, for example. Back in 1999, NASA’s Chandra X-ray Observatory was launched in order to observe the high-energy Universe including such things as colliding galaxies, black holes, and supernova remnants.

One such supernova remnant that Chandra studies is Cassiopeia A. About 400 years ago, in our own Milky Way galaxy, a star that was about 15 to 20 times the mass of our Sun, detonated in a supernova explosion.

Smaller Stars Pack Big X-ray Punch For Would-be Planets

TW Hya
Young stars much less massive than the Sun can unleash a torrent of X-ray radiation that can significantly shorten the lifetime of planet-forming disks surrounding these stars. This result comes from a new study of a group of nearby stars using data from NASA's Chandra X-ray Observatory and other telescopes.

Researchers found evidence that intense X-ray radiation produced by some of the young stars in the TW Hya association (TWA), which on average is about 160 light years from Earth, has destroyed disks of dust and gas surrounding them. These disks are where planets form. The stars are only about 8 million years old, compared to the 4.5-billion-year age of the Sun. Astronomers want to learn more about systems this young because they are at a crucial age for the birth and early development of planets.

Coding (and Coloring) the Universe

Micro to macro
Micro to macro
Illustration: NASA/CXC/K.Divona

When people ask me what I do for work, I often say that I’m a storyteller. It’s not that I stand on a stage with a microphone and narrate long tales to a rapt audience.

My stories are told differently, not through voice or music, but through lines of code and technical applications. They are stories, of science.

As an undergraduate, I began my career in molecular biology, looking at the tiny organisms that can transmit Lyme disease to humans aboard the Ixodes Scapularis (a.k.a., the Deer tick). But by the time I graduated, I was moving on to learn about another type of science: that of computers.

Pages

Disclaimer: This service is provided as a free forum for registered users. Users' comments do not reflect the views of the Chandra X-ray Center and the Harvard-Smithsonian Center for Astrophysics.
Please note this is a moderated blog. No pornography, spam, profanity or discriminatory remarks are allowed. No personal attacks are allowed. Users should stay on topic to keep it relevant for the readers.
Read the privacy statement