Posts Tagged ‘Hubble space telescope’

Everyone can be The Astronomer

Tuesday, March 3rd, 2009 by admin

The year 2009 is the international year of astronomy; it marks 400 years since Galileo used the telescope to first look up at space. As part of the celebration NASA and other astronomical societies having been doing things to celebrate.  NASA is doing its part this month by allowing the public to be the astronomers. They have put the public in control of the Hubble Space Telescope. NASA has picked six astronomical objects and is allowing the public to vote on which object Hubble will view and collect data on next. I decided to go over each of the six objects and describe what they are and why they might be of interest.

The first object is a star-forming region called NGC 6334 also known as the Cat’s Paw Nebula or the Bear Claw Nebula. It is located in the Scorpius constellation that is located in the southern hemisphere near the center of the galaxy.  It is located about 5,500 light years away. It glows with a deep red color that originates from a large amount of ionized hydrogen in the area. The nebula is usually obscured by large amounts of gas and dust sometimes making it difficult to observe from ground based telescopes.  The region is a very active star-forming region, which is the reason it is considered for observation. Observing these star forming regions tells us a lot about the birth and evolution of stars, and the interaction of a large number of young stars in close proximity to each other.

The second contestant is the planetary nebula NGC 6072, which is also located in the constellation Scorpius. There is not much information available on this object and it has not been viewed very often.  It is a remnant of a dead low mass star; a white dwarf with an envelope of gas and molecules surrounding it that were puffed off layers of the star as it was dying. Observing planetary nebulas is always useful, it gives us information about stars after they die and how the elements given off interacts with surrounding gas and dust. They also usually make for very pretty pictures.

The third object is planetary nebula NGC 40, otherwise known as the Bow-Tie Nebula. It is located about 3,500 light years form Earth in the constellation Cepheus. It is also composed of hot gas surrounding a dying/dead star. The white dwarf left behind radiates at about 50,000 degrees C and the gas envelope at about 30,000 degrees C.  This nebula has been imaged more than the other nebula, perhaps making it a less attractive candidate.

The fourth object in the contest is the spiral galaxy NGC 5172.  It is located at a distance of about 57 mega parsecs or about 150 million light years. It is a spiral type Sbc. IT has been a host to several well-documented supernovae. From what we can tell it is very similar in size and shape to our own Milky Way galaxy, which is the reason it may be a good candidate for study. Since we can not get an outside looking in view of our own galaxy studying ones similar to our own tell us information we could not otherwise get.

The next possible object is the edge on galaxy known as NGC 4289. It is located in the Virgo Constellation about 50 million light years away.  It is also a spiral galaxy but instead of being viewed face on it is seen completely edge on.  There are advantages to looking at the same types of things from different views; especially with astronomy. When looking at things so far away with things obstructing your view, light traveling so far, being bent around objects being able to see galaxies edge on can help with verifying measurements of brightness, velocity and other variables.

The last option for an object to choose is Arp 274, or NGC 5679, and is actually two (possibly three) galaxies interacting with each other.  It is also located in the Virgo constellation. Interacting galaxies are treasure-troves of data. By studying them we can information on formation and evolution or galaxies. We get information on how these interactions affect star formation, surrounding galaxies, central black holes, and more. I think this is a great candidate for further study. 

So those are the six objects open for voting. I encourage any readers to go check out NASA’s site and vote. I personally think this was a great idea on NASA’s part. Hubble has always been very popular and a great tool for creating public interest in astronomy, which can at times be hard to do.  I think it’s smart to give the general people the option to pick what they think is interesting and what they want to know more about. I encourage anything that the industry wants to do to try and rose public support, especially in times when funding is hard to come by NASA needs to keep the public in its corners.  I’m excited to see who the winner will be. 

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Fast As A Speeding Star

Monday, March 2nd, 2009 by Bellatrix

Using the Hubble Space Telescope, NASA scientists have discovered stars doing something very interesting: speeding around through the interstellar medium.  This came as quite a surprise especially since they were not even looking for them. This is not usual behavior for stars and brings up many new questions about what these stars are doing and why.

The scientists discovered 14 of these crazy runaway stars.  Because of their movement it was harder to gather information about them but scientists were able to deduce some facts about the stars. The stars appear to be young, maybe only about a million years old.  This was deduced from looking a their strong stellar winds. Most stars only have such winds when they are quite young or very old. The nebulae around the stars do not math that of those typically seen around old dying stars. And only very massive stars have winds throughout their lifespan, but these stars could not be that massive because they do not have glowing clouds of ionized gas around them. They are estimated to be about 2 to 8 solar masses.

These stars plow through regions of dense interstellar gas creating brilliant arrowhead shaped glowing bow shocks and trailing tails of glowing gas. These bow shocks are created when the strong winds coming from the stars slam into the surrounding dense gas. It’s difficult to tell their exact distance from Earth but depending on the distance these bow shocks could be 100 billion to a trillion miles wide. By studying these bow shocks we can tell that the stars are moving very quickly, about 180,000 km/hr.  All stars are moving as they are orbiting around the galaxy but not nearly at these speeds, the sun for comparison moves through the galaxy at only about 13,000 km/hr.  Assuming this “young” phase lasts only a million years the stars would have traveled about 160 light years.

The scientists have hypothesized that these stars were likely kicked out or ejected from massive star clusters.  There’s two possible ways this expulsion could have happened.  One way is if a binary system, consisting of two stars orbiting each other, had one star go supernova the explosion would eject the companion star.  The other possibility would be if two binary systems or a binary and a third star collided one of the stars could have used he energy from the interaction to escape the system.

Runaway stars have been observed before, the first being found in the late 80s. However, those stars produced much larger bow shocks meaning they were probably more massive with larger stellar winds.  Scientists think these new objects, the medium size stars, are probably more common since medium sized stars are more common in general and because they would be more susceptible to being ejected.  These objects are difficult to find and observe because one doesn’t know where to find them or where to look for them. 

Follow up studies are planned to look for more of these objects, called interlopers, and to study these recently discovered ones. Further studies will tell us more about the effects these speed demons have on the environments they pass by or interact with. Theorists and modelers will have to set to work on looking at the origins of the objects and the causes of their ejections. Pretty interesting to think about these stars being expelled from their homes now doomed to zoom around the galaxy alone. 

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Galaxy Having a Major Baby Boom

Monday, October 27th, 2008 by Bellatrix

Astronomers have discovered a distant galaxy making stars at an amazing rate. It is creating stars at a rate more than a thousand times that of the Milky Way, but the remarkable thing about it is its extreme distance. This galaxy may call into question the current theory of how galaxies form.

The galaxy, nicknamed the baby boom galaxy, is making stars at a rate of about 4000 per year, compared to the Milky Way, which makes only 10 stars per year. This galaxy is also located very far from us, 12.3 billion light years. We have observed other starburst galaxies before, but none this far away, or similarly this old. This galaxy is a very young galaxy, since it is so far, we are looking at it as it was almost 12 billions years ago. That gives this galaxy the record for furthest (or youngest) starburst galaxy ever observed. The furthest before this one was 11.7 billion light years from us.

Now this galaxy calls into question the current most popular model for how galaxies are believed to form, called the hierarchal model. This model states that galaxies form slowly by consuming other smaller galaxies and star clusters, thus the stars in the galaxies should all have different birthdays. However, with this new galaxy all the stars will have very similar birthdays, meaning formation of around the same time. So the question now is whether this case is the norm or the exception. With this kind of star formation we may be witnessing the birth of one of the most massive elliptical galaxies in the universe.

The discovery of this was only possible through combined use of several different telescopes. Measurements in the radio wavelengths were made with the National Science Foundation’s Very Large Array in New Mexico. Infrared data was used from both the Spitzer space telescope and the James Clerk Maxwell Telescope on Mauna Kea Hawaii. Visible light images were used from both the Hubble Space Telescope and Japan’s Subaru Telescope also atop Mauna Kea. The identification of this galaxy and its properties would not have been possible without observations in the full range of the light spectrum. So its discovery is a fine example of the combination of different available technologies, from different sponsoring organizations. Now that we know how to find them, i.e. using data from across the electromagnetic spectrum, hopefully we can find out if galaxy baby booms were common in the distant universe, and if not, what is special about this case.

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