Profile

Cover photo
Roger Abella Queralt (DeMS)
Lives in Barcelona
4,613 followers|135,033 views
AboutPostsPhotosYouTube

Stream

 
 
A T Tauri star looks like a red or orange star. Their surface temperature is a bit cooler than the Sun’s, but they are brighter than a typical main-sequence star of the same type. The reason for this is that they have not finished collapsing, so they are larger than a similar mass star. Their heat is not generated by fusion in their core, but rather from their gravitational collapse. They also produce a great deal of stellar wind.
The image above is of a star known as T Tauri. T Tauri is the prototype (primary example) of T Tauri type stars. In many ways T Tauri is a star in the making. Not quite a main sequence star, but more than a protostar.
2 comments on original post
3
Add a comment...
 
 
Comet PanSTARRS with Galaxy
Image Credit & Copyright: Alessandro Falesiedi
http://apod.nasa.gov/apod/ap140606.html

Sweeping slowly through northern skies, the comet PanSTARRS C/2012 K1 posed for this telescopic portrait on June 2nd in the constellation Ursa Major. Now in the inner solar system, the icy body from the Oort cloud sports two tails, a lighter broad dust tail and crooked ion tail extending below and right. The comet's condensed greenish coma makes a nice contrast with the spiky yellowish background star above. NGC 3319 appears at the upper left of the frame that spans almost twice the apparent diameter of the full Moon. The spiral galaxy is about 47 million light-years away, far beyond the stars in our own Milky Way. In comparison, the comet was a mere 14 light-minutes from our fair planet. This comet PanSTARRS will slowly grow brighter in the coming months remaining a good target for telescopic comet watchers and reaching perihelion, its closest approach to the Sun, while just beyond Earth's orbit in late August.
24 comments on original post
2
1
Allan Parks's profile photo
Add a comment...
 
 
Testing Metal

In astronomy, all elements other than hydrogen and helium are referred to as “metals.” For this reason, a measure of the amount of other elements a star contains is known as its metallicity. One way to define the metallicity of a star is simply as the fraction of a star’s mass which is not hydrogen or helium. For the Sun, this number is Z = 0.02, which means that about 2% of the Sun’s mass is “metal”. Another way to express the metallicity of a star is by its ratio of Iron to Hydrogen, known as [Fe/H]. This is given on a logarithmic scale relative to the ratio of our Sun. So the [Fe/H] of our Sun is zero. Stars with lower metallicity will have negative [Fe/H] values, and ones with higher metallicity have positive values.When it comes to planetary systems, it’s generally been thought that planets would tend to form around stars with a higher metallicity. At a broad level that makes sense because rocky planets such as Earth can only form in a system where there are enough metals like iron, silicon, carbon and the like.  You can’t make a terrestrial planet out of just hydrogen and helium.  But now that we’ve discovered lots of exoplanetary systems, we can actually put this idea to the test. A recent paper in Nature has done just that, and they’ve found something rather interesting.

In the paper, the authors looked at about 400 stars with exoplanets (about 600 exoplanets in all).  They then compared the size of the exoplanets with the metallicity of their stars.  What they found was that there was a distinct relation between the metallicity of a star and the type of planets it has.  Stars with a metallicity similar to our Sun’s were more likely to have terrestrial planets, while stars with higher metallicity tend to have gas dwarfs, or gas giants (Jupiter-like).  The study also showed that high metallicity stars are likely to have so-called “hot-Jupiters”. That is, large gas giants orbiting close to a star.

We’ve seen in computer models how large protoplanets will tend to migrate inward toward the star as they form. This new work would seem to support that idea, since higher metallicity stars would be more likely to form gas giants early on, thus allowing them to migrate inward to become hot Jupiters.

So it seems that metallicity is a significant factor in planetary formation, and higher metallicity stars will tend to form larger planets.  But it also seems that stars similar to the Sun are better suited for having terrestrial planets like ours.

Image: From the paper.

Paper: Lars A. Buchhave, et al. Three regimes of extrasolar planet radius inferred from host star metallicities. Nature 509, 593–595 (2014)
9 comments on original post
1
Add a comment...
 
 
One Does Not Simply Telnet into Mordor...but they can ssh ;-)  #linux
80 comments on original post
6
Awk Man's profile photo
Awk Man
+
1
2
1
 
+Roger Abella Queralt  Veo que también te mola el espacio y frikadas informáticas!
 ·  Translate
Add a comment...
 
 
The universe is billions of years old, and we humans have only been observing it for a tiny fraction of all that time.  How is it, then that we can know things like the age of stars, how they form and die?  It would be like an alien race learning about humanity by observing us for only a fraction of a second.
Suppose an advanced alien race discovered our little planet. From their great telescopes they could tell our atmosphere is rich in oxygen and water vapor, which would indicate this was a planet inhabited by living organisms. They therefore decide to send a probe to study our curious blue world. With their advanced technology, this alien species can send a probe across the vast distance of space using a device they call the Maguffin drive. The Mag...
6 comments on original post
1
Add a comment...
 
 
Rumor Weed

Yesterday there was a flurry of news about a gamma ray burst (GRB) appearing in the Andromeda galaxy.  This would make it the closest observed gamma ray burst, which would be a boon for astronomers.  News of this discovery travelled fast, particularly on Twitter and other social networks.  Pretty soon a few news sites had picked up the story. But it turns out it wasn’t a gamma ray burst.  

It all started with a space telescope known as Swift.  Swift is designed to study gamma ray bursts, and one of its detectors is a wide field telescope known as the Burst Array Telescope (BAT).  The BAT is designed to look for bursts of high energy radiation from unknown sources.  If it detects one, it “triggers” and sends an alert so that other telescopes can be position to observe the event.  Gamma ray bursts can be short lived, so time is of the essence.

Normally the level needed for the BAT to trigger is pretty high (6.5 sigma for you statisticians) so that it doesn’t cry wolf all the time (what are known as spurious events).  But the bar is set a bit lower if the energy burst seems to be from a nearby galaxy.  So Tuesday night (EDT) BAT detected a burst, and Swift’s x-ray telescope also observed a burst of x-rays.  The burst also happened to be in the direction of the Andromeda galaxy.  So it triggered and the alert went out.

Naturally, some of the astronomers working in this area of research use Twitter, and started tweeting about a possible GRB in Andromeda.  This was picked up by their fans and other astronomers, and the whole thing cascaded.  It turns out it was a known x-ray source, probably an x-ray binary.  So while it initially looked promising, it turned out to be a spurious event.  Sometimes this happens, and it is better to have the occasional false alarm rather than miss an important event.

Of course all of this played out in the social media circles, and its seems rather chaotic at the time. It also means sometimes things get reported as far more certain than they actually are.  If you actually look at what is being said, however, you’ll see something rather interesting.  If you go back and look at the comments, such as those tagged with #GRBM31 on Twitter, you’ll notice that the astronomers are pretty careful about saying things like “possible” GRB.  They spread the tentative news, and start looking for evidence to confirm or deny the event.  As they learn things from a clear source, they start tweeting that as well.  You’ll also note there is a great deal of excitement.

This is part of what makes science interesting.  Cool things happen, even if we later find out it isn’t as cool as we thought.
24 comments on original post
3
Add a comment...
 
 
Meet The Newest Classification For Planets: The Gas Dwarf

We just got a new kind of planet! Learn about these worlds at:
http://bit.ly/1oX2cXv

Image via NASA
3 comments on original post
5
Add a comment...
 
 
Venus and Earth are very similar, but Venus is a dry planet while Earth is wet.  Why is that? Several models have been proposed, but it might be as simple as their distance from the Sun.
Venus and Earth are quite similar in many ways. The diameter of Venus is about 95% of Earth’s, its mass is about 80% of Earth’s, it has a similar geological make up, and surface gravity. Where they differ greatly is in their surface temperature. Venus has a surface temperature of over 800 degrees Fahrenheit, while Earth’s average temperature is around 57 degrees (460 C vs 14 C for you science types). They also differ in the amount of water they h...
5 comments on original post
1
Awk Man's profile photo
Awk Man
+
1
2
1
 
Venus es diferente a la Tierra debido al efecto invernadero que tiene, no por la distancia al Sol. En un capítulo de la nueva serie de Cosmos hablan de esto
 ·  Translate
Add a comment...
 
 
So this is potentially useful - a colour generator Sure, at first i was like why is this getting so much attention, but then I saw its implementation is quite elegant - you can ask it for random colours of a given hue for example (as illustrated below) http://llllll.li/randomColor/
View original post
1
Add a comment...
 
 
Astronomers Confounded By Massive Rocky World - Astronomers have discovered a rocky planet that weighs 17 times as much as Earth and is more than twice as large in size. This discovery has planet formation theorists challenged to explain how such a world could have formed. Worlds such as this were not thought possible to exist. More: http://go.nasa.gov/1n5z2SF 

This image is an artist concept. Credit: Harvard-Smithsonian Center for Astrophysics/David Aguilar

#planets #nasa #kepler #astronomy #science #exoplanet #earth
182 comments on original post
4
Muhammad Rinaldi's profile photo
Add a comment...
 
 
One of the ways in which astronomy and astrophysics differ is that astronomy is concerned with observed phenomena, and astrophysics is concerned with the mechanism behind the phenomena.  This means that sometimes we discover radically different phenomena have a common cause.
One of the differences between astronomy and astrophysics is that astronomy is based upon observation, while astrophysics is about the underlying mechanism behind those observations. For this reason, many types of phenomena in the universe have multiple names depending on how we observe them. The reason for this is that typically astronomers start observing different phenomena, give them names, and then only later do astrophysicists figure out th...
5 comments on original post
1
Add a comment...
 
 
Rumor Weed

Yesterday there was a flurry of news about a gamma ray burst (GRB) appearing in the Andromeda galaxy.  This would make it the closest observed gamma ray burst, which would be a boon for astronomers.  News of this discovery travelled fast, particularly on Twitter and other social networks.  Pretty soon a few news sites had picked up the story. But it turns out it wasn’t a gamma ray burst.  

It all started with a space telescope known as Swift.  Swift is designed to study gamma ray bursts, and one of its detectors is a wide field telescope known as the Burst Array Telescope (BAT).  The BAT is designed to look for bursts of high energy radiation from unknown sources.  If it detects one, it “triggers” and sends an alert so that other telescopes can be position to observe the event.  Gamma ray bursts can be short lived, so time is of the essence.

Normally the level needed for the BAT to trigger is pretty high (6.5 sigma for you statisticians) so that it doesn’t cry wolf all the time (what are known as spurious events).  But the bar is set a bit lower if the energy burst seems to be from a nearby galaxy.  So Tuesday night (EDT) BAT detected a burst, and Swift’s x-ray telescope also observed a burst of x-rays.  The burst also happened to be in the direction of the Andromeda galaxy.  So it triggered and the alert went out.

Naturally, some of the astronomers working in this area of research use Twitter, and started tweeting about a possible GRB in Andromeda.  This was picked up by their fans and other astronomers, and the whole thing cascaded.  It turns out it was a known x-ray source, probably an x-ray binary.  So while it initially looked promising, it turned out to be a spurious event.  Sometimes this happens, and it is better to have the occasional false alarm rather than miss an important event.

Of course all of this played out in the social media circles, and its seems rather chaotic at the time. It also means sometimes things get reported as far more certain than they actually are.  If you actually look at what is being said, however, you’ll see something rather interesting.  If you go back and look at the comments, such as those tagged with #GRBM31 on Twitter, you’ll notice that the astronomers are pretty careful about saying things like “possible” GRB.  They spread the tentative news, and start looking for evidence to confirm or deny the event.  As they learn things from a clear source, they start tweeting that as well.  You’ll also note there is a great deal of excitement.

This is part of what makes science interesting.  Cool things happen, even if we later find out it isn’t as cool as we thought.
24 comments on original post
1
Add a comment...
People
Have him in circles
4,613 people
Daniela Vera's profile photo
Jonet Bedoyo's profile photo
Philip Hodges's profile photo
Juliana Santos's profile photo
Daniel McGuire's profile photo
DatTomLPs's profile photo
World News's profile photo
Movie Buzzer's profile photo
Marvin Photographie's profile photo
Basic Information
Gender
Male
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Barcelona
Previously
Playa de Aro - Tàrrega