New Scientist: Astrophile

[bystander]

New Scientist: Astrophile

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[bystander]

Trio of dead stars could take on Einstein
New Scientist | Astrophile | Jacob Aron | 2014 Jan 06

[b]Morbid threesome: a millisecond pulsar [i](left foreground)[/i] is orbited by a hot white dwarf star [i](centre)[/i], both of them orbited by a more distant and cooler white dwarf [i](top right) (Image: Bill Saxton; NRAO/AUI/NSF)[/i][/b]

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Objects: A fast-pulsing star and two white dwarfs
Location: A rare triple-star system

The three friends had been through a lot over the years. One had an explosive personality that in the early days nearly drove the friends apart, but has since settled down to ticking away the time. The two others have a complicated relationship with the clock-watcher, one preferring to stick close by, while the other keeps its distance. Together, the trio are attempting to put Einstein to the test.

Systems composed of three ordinary stars are common throughout the galaxy. But because exotic stars like pulsars or white dwarfs form in violent explosions that often shove companions away, they tend to go it alone. But now astronomers have found the first example of a triple system containing only the strange corpses of burned-out stars, and they plan to use it to probe the nature of gravity. ...

Pulsar in a Stellar Triple System Makes Unique Gravitational Laboratory
National Radio Astronomy Observatory | 2014 Jan 05

A millisecond pulsar in a stellar triple system - S. M. Ransom et al

• Nature 505(7484) 520 (23 Jan 2014) DOI: 10.1038/nature12917
  arXiv.org > astro-ph > arXiv:1401.0535 > 02 Jan 2014

[bystander]

Binary stars that form like fraternal twins
New Scientist | Astrophile | Rebecca Boyle | 2014 Jan 14

[attachment=0]stars_4.jpg[/attachment]

Object: Binary stars
Formation mechanism: In the same stellar nursery

Protostar CB230 IRS1 never let anyone forget that he was the older twin. Although he and his brother were born of the same swirling mass of gas and dust, IRS1 knew that he coalesced first. The second star in the binary duo formed after the spinning disc fragmented, and congealed into a smaller star. And like human fraternal twins, though they were born in the same environment, the pair will grow up to look very different. The bigger twin will die first, and if the pair stay close enough throughout their lives, it could even turn into a supernova.

Astronomers have debated how binary stars, which make up about half of all sun-like stars in the galaxy, form and grow up. Some argue binaries are like twins, whether identical – beginning their existence as one entity and dividing in two early on – or fraternal – both forming from scratch in the same proto-stellar disc. Others think they're more like lovers who found each other later in life, migrating across interstellar space until gravity joins them for good. ...

New Studies Give Strong Boost to Binary-Star Formation Theory
National Radio Astronomy Observatory | 2013 Dec 31

VLA and CARMA Observations of Protostars in the Cepheus Clouds:
Sub-arcsecond Proto-Binaries Formed via Disk Fragmentation - John J. Tobin et al

• Astrophysical Journal 779(2) 93 (2013 Dec 20) DOI: 10.1088/0004-637X/779/2/93
  arXiv.org > astro-ph > arXiv:1310.5154 > 18 Oct 2013

[bystander]

Giant flashlight illuminates cosmic network
New Scientist | Astrophile | Lisa Grossman | 2014 Jan 19

[attachment=0]First_Image_of_Cosmic_Web.png[/attachment]

Object: Ancient strand of gas and dark matter
Size: 2 million light years across

The cobwebby filaments that stretched between galaxies in the early universe have shown themselves for the first time. Light from the activity of a distant supermassive black hole is serving as a giant cosmic flashlight, illuminating an enormous strand of gas held together by invisible dark matter.

The geometry of large-scale cosmic structures helps us piece together the processes that formed the universe. Though this first glimpse mostly fits with existing models, there is one surprise that suggests some processes are currently missing in our understanding.

Theory and simulations of the evolution of the universe suggest that, as the universe cooled after the big bang, dark matter settled into a network of filaments that criss-crossed the cosmos. The greater gravity at points where these strands crossed drew in ordinary matter, which eventually grew dense enough to ignite stars and develop galaxies and galaxy clusters. ...

Distant quasar illuminates a filament of the cosmic web
University of California, Santa Cruz | 2014 Jan 19

A cosmic web filament revealed in Lyman-alpha emission around a luminous high-redshift quasar - Sebastiano Cantalupo et al

• Nature 506(7486) 63 (06 Feb 2014) DOI: 10.1038/nature12898
  arXiv.org > astro-ph > arXiv:1401.4469 > 17 Jan 2014

http://asterisk.apod.com/viewtopic.php?t=32786

[bystander]

Jellyfish galaxies found spawning in clusters
New Scientist | Astrophile | Lisa Grossman | 2014 Jan 28

[attachment=0]CometGalaxy.jpg[/attachment]

Object: Jellyfish galaxies
Habitat: Crowded clusters of cosmic blobs

The large spiral galaxy was tired of being alone. It had been ages since its last relationship with another galaxy, and they had enjoyed a long, slow dance in each other's orbit. When they finally merged, the spiral felt like it had done some serious growing, and it wanted even more social interaction. But it turns out that spiral galaxies need to change in a much more fundamental way if they want to move in with groups of friends.

A hunt through images from the Hubble Space Telescope has turned up half a dozen spiral galaxies that are being ripped apart and remade into jellyfish – with blobby bodies and glowing tendrils of stars – as they move towards joining galaxy clusters. It is thought that this process ultimately turns spirals into elliptical-shaped galaxies. That means the discovery, which more than doubles the number of known jellyfish galaxies, should help researchers better understand why such "ellipticals" are more common in clusters than their spiral cousins. ...

Jellyfish: Evidence of extreme ram-pressure stripping in massive galaxy clusters - Harald Ebeling et al

• Astrophysical Journal Letters 781(2) L40 (2014 Feb 01) DOI: 10.1088/2041-8205/781/2/L40
  arXiv.org > astro-ph > arXiv:1312.6135 > 20 Dec 2013 (v1), 24 Jan 2014 (v2)

[MargaritaMc]

I had been regularly posting the Astrophile columns, but I've fallen 6 or 7 months behind. I liked the column and I'm going to try to catch it up.

It's a very useful column and I often miss new items as they don't seem to be on a regular basis. So I'm very pleased you are posting these, bystander - MUCH appreciated!

Margarita

[bystander]

Wrinkles reveal Mercury's rapid slimming
New Scientist | Astrophile | Marcus Woo | 2014 Mar 16

[attachment=0]mercury.jpg[/attachment]

Object: Mercury's many wrinkles
Source: A cooling, crumpling crust

Mercury just wanted to look its best. As the years rolled by the planet was losing the fire of its youth, but it was also slimming down, shedding a few pesky kilometres from its round, rocky body. Then the wrinkles started to sprout…

When the solar system formed about 4.6 billion years ago, Mercury was a hot ball of molten material. The tiny planet cooled quickly, shrinking in size and causing its relatively thin crust to crumple up. The shrinking seems to have slowed down after about a billion years, but the grey, pockmarked world we see today is crisscrossed by steep crustal ridges that reveal the period of rapid contraction. ...

Mercury’s Contraction Much Greater Than Thought
Carnegie Institution for Science | 2014 Mar 18

The Incredible Shrinking Mercury
MESSENGER | JHU-APL | CIS | 2014 Mar 19

Mercury's global contraction much greater than earlier estimates - Paul K. Byrne et al

• Nature Geoscience 7(4) 301 (2014) DOI: 10.1038/ngeo2097

[bystander]

Dizzy exoplanet has a compact 8-hour day
New Scientist | Astrophile | Jacob Aron | 2014 Apr 30

[i]Feels like the days are getting shorter... (Image: ESO L. Calçada/N. Risinger)[/i]

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Object: Young gas giant
Rotation rate: 25 kilometres a second

Do you feel there is never enough time in a day? Then don't move to Beta Pictoris b. A day on this fast-paced exoplanet lasts just 8 hours, making it a poor choice for the temporally challenged. You would also be battling a dusty atmosphere, searing temperatures and a total lack of solid ground on this Jupiter-like gas giant.

Beta Pictoris b was discovered in 2008 orbiting a young star about 63 light years away. Astronomers think the planet is about 7 times as massive as Jupiter and is still glowing with the heat of its own formation, at a temperature of roughly 1600 kelvin. ...

Length of Exoplanet Day Measured for First Time
European Southern Observatory | VLT | 2014 Apr 30

Fast spin of the young extrasolar planet β Pictoris b - Ignas A. G. Snellen et al

• Nature 509(7498) 63 (01 May 2014) DOI: 10.1038/nature13253
  arXiv.org > astro-ph > arXiv:1404.7506 > 29 Apr 2014

http://asterisk.apod.com/viewtopic.php?t=33325

[geckzilla]

Jellyfish galaxy is a delightful name for that phenomenon. Much better than Catherine wheel...

[bystander]

Big blue star is an X-ray oddball
New Scientist | Astrophile | Jesse Emspak | 2014 Jun 16

[i]Xi-1 Canis Majoris, centre, is less blue in X-ray images (Image: ESA/XMM-Newton/L. Oskinova (University of Potsdam))[/i]

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Object: Xi-1 Canis Majoris
Superpower: Surprise X-ray pulses

Sometimes monsters hide in plain sight, and it takes a hero with X-ray vision to find them.

A European space telescope has spotted a massive star that is pulsing with brilliant X-rays. Studying the bizarre beast might yield important insights into stellar evolution, for instance, why some stars have strong magnetic fields while others don't, and what controls their powerful winds of charged particles.

The European Space Agency's XMM-Newton satellite has been zooming overhead since 1999, revealing details about objects such as galaxies, stars and black holes based on the X-rays they emit. Lidia Oskinova at the University of Potsdam in Germany and her colleagues were using the telescope to take a closer look at Xi-1 Canis Majoris, a large blue star near the constellation Canis Major. ...

Pulsating X-rays allow XMM-Newton to unmask a mysterious star
ESA Science & Technology | XMM-Newton | 2014 Jun 03

Discovery of X-ray pulsations from a massive star - Lidia M. Oskinova et al

• Nature Communications 5 4024 (03 Jun 2014) DOI: 10.1038/ncomms5024
  arXiv.org > astro-ph > arXiv:1406.0845 > 03 Jun 2014

http://asterisk.apod.com/viewtopic.php?t=33550

[bystander]

Jellyfish galaxy is a delightful name for that phenomenon. Much better than Catherine wheel...

I thought I had seen that image before, but I couldn't find it. I've tried to put link backs to previous topics but I might have missed some.

edit: Wikipedia calls it the Comet Galaxy.
I think it is a cut from the Hubble image of Abell 2667
(ESA/Hubble & NASA/STScI HubbleSite).

Another example: ESO 137-001 in Abell 3627.

[geckzilla]

That galaxy is really funny. It's like it got slapped it across the face and blood and saliva stars went flying in the direction of the slap.

[MargaritaMc]

That galaxy is really funny. It's like it got slapped it across the face and blood and saliva stars went flying in the direction of the slap.

Not quite so dramatic, but helped me see what was happening.

Click to play embedded YouTube video.

This is the one I was trying to find!

Click to play embedded YouTube video.

This cluster is violently ripping the spiral's entrails out into space, leaving bright blue streaks as telltale clues to this cosmic crime.

Not the same galaxy by the way! Just ram pressure stripping in action.

[bystander]

That galaxy is really funny. It's like it got slapped it across the face and blood and saliva stars went flying in the direction of the slap.

ESA/HEIC: Spiral galaxy spills blood and guts

Not quite so dramatic, but helped me see what was happening.
PR Video heic1404d

Here are a two more animations from ESA/HEIC: PR Video heic0705c & PR Video heic0705d

[Ann]

Thanks for the Astrophile postings, bystander! Very interesting.

Ann

[MargaritaMc]

Here are a two more animations from ESA/HEIC: PR Video heic0705c & PR Video heic0705d

Duh! I never thought to look for them at the Hubble site! I've bookmarked the video section now - much easier to find things there than at YouTube. Thank you!