Turbulence explains magnetic field misbehavior in solar flares

Turbulence explains …

When a solar flare filled with charged particles erupts from the Sun, its magnetic fields sometime break a widely accepted rule of physics. The flux-freezing theorem dictates that the magnetic lines of force should flow away in lock-step with the…

Turbulence explains …
Accurate distance measurement resolves major astronomical mystery

Accurate distance me…

Sometimes astronomy is like real estate — what’s important is location, location, location. Astronomers have resolved a major problem in their understanding of a class of stars that undergo regular outbursts by accurately measuring the distance to a famous example…

Accurate distance me…
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Archive for astronomy astrophysics

Celestia – The Astronomy and Astrophysics Club of BITS Goa

By alkaon on December 25, 2012 No Comments



Celestia is the Astronomy and Astrophysics club of BITS Pilani Goa Campus and no, they are not a a group of students who simply strain their necks looking at nothing in particular in the night sky, as is the popular perception. They are an extremely talented and dedicated bunch whose sole aim is to promote astronomy and astrophysics in the the campus. The club which has members across all years is on a never ending quest to find answers to: What is the cosmos?
Why are we here? Why is the cosmos the way it is? and other such fundamental questions.

The Club, which was formed in 2009, periodically organizes Lectures Guest Talks by eminent physicists scientists from IUCAA, TIFR, NASA, ISRO, CERN. Apart from this it also holds observational tours. In spring of 2012, the club organized its first all night star observation session in collaboration with AFA (Association for Friends of Astronomy) in Goa. To themselves update about regular developments in the field, they also have a Student Lecture Series- where members of the club take lectures on current topics of their own interests like quantum tunneling , Meisser objects, Einstein equations, dark matter dark energy,etc. To its credit the club organized one of its mega events Storming Aurora on 18th November this year on campus where eminent researchers like Dr Dan Werthimer, co- founder of SETI (Search for Extra Terrestrial Intelligence), Dr Urvashi Rao, Assistant Scientist at National Radio Astronomy Observatory (NRAO)-New Mexico, Prof. Subhendra Mohanty, professor at the Physical Research Laboratory-Ahmedabad, Dr Ramesh Koul (HOD Astrophysics, BARC), Pushkar Vaidya-head of IARC (Indian Astrobiology Research Centre), Niruj Mohan Ramanujam-from the team which controls the GMRT (Giant Metrewave Radio Telescope) near Pune, spoke about their fields of interest. To know more about Storming Aurora refer to this article.

Celestia recently uncovered its very first astronomy astrophysics based magazine which is now live on Scribd called – “Cosmic Times”, a copy of which is available in the library. An online copy is also available for download: http://www.scribd.com/doc/113779560/Cosmic-Times

Do visit Celestia’s official website: http://celestiaclub.org/ for more updates and to appreciate the great scientific fervor and dedication shown by this group of thinkers.

Article source: http://www.coolage.in/2012/12/25/celestia-the-astronomy-and-astrophysics-club-of-bits-goa/

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OD and SH – two new molecules in space

By alkaon on May 11, 2012 No Comments


The first series of astronomical observations with the German Receiver for Astronomy at Terahertz Frequencies (GREAT) on board the Stratospheric Observatory for Infrared Astronomy (SOFIA) has been successfully completed in November last year. Now, six months later, the scientific results are published in a special issue of the prestigious European Journal Astronomy Astrophysics. In a total of 22 articles an international group of scientists reports on unique first astronomical results as well as the technologies used.


OD and SH - two new molecules in space

SOFIA, the “Stratospheric Observatory for Infrared Astronomy” cruises above Southern California with its large cavity door wide open; the 2.7-meter German-built telescope is visible. At altitudes of up to 45000 ft the observatory operates above 99.8% of the atmospheric water vapor. Credit: NASA

A joint project between NASA and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), SOFIA operates a 2.7-m telescope in a modified Boeing 747SP aircraft and is the world’s only operational airborne observatory. SOFIA flies at altitudes as high as 13700 meters to provide access to astronomical signals at far-infrared wavelengths that would otherwise be blocked due to absorption by water vapor in the atmosphere. The SOFIA observatory opens the far-infrared skies for high-resolution spectroscopy with GREAT, while GREAT pushes its technology to higher frequencies and sensitivities than ever reached before.

“The high resolving power of the GREAT spectrometer is designed for studies of the interstellar gas and the stellar life cycle, from a protostar’s early embryonic phase when still embedded in its parental cloud, to an evolved star’s death when the stellar envelope is ejected back into space”, says Rolf Güsten from the Max Planck Institute for Radio Astronomy (the Principal Investigator of the GREAT project. “This stunning collection of first science results is the reward for the many years of development work, and underlines the scientific potential of airborne far-infrared spectroscopy.”


OD and SH - two new molecules in space
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The GREAT far-infrared spectrometer is mounted to the telescope flange, inside the pressurized cabin. During observations GREAT rotates ±20 degrees from the vertical. R. Güsten

Many of the contributed papers study the star formation process in its earliest phases, when the embryonic star is vigorously interacting with its surrounding parental molecular clouds –tearing them apart and ionizing them. The high spectral resolution capabilities of GREAT allowed resolving the velocity field of the gas in the parental molecular clouds traced by the important cooling line radiation of ionized carbon in several star forming regions. GREAT detected the velocity signature of collapse in the envelopes of three protostars, directly probing the dynamics of a forming star. Two interstellar molecular species were detected for the first time ever: OD, an isotopic substitute of hydroxyl (OH) with the hydrogen atom replaced by the heavier deuterium, and the mercapto radical SH. Pushing to technological frontiers, observations of the ground-state transition of OH at 2.5 Terahertz (120 µm wavelength) explore new astrophysical territories. The remnant envelope of an evolved star, ionized by its hot stellar core, was investigated and the violent shock interaction of a supernova remnant with the surrounding interstellar medium. The nature of the accretion disk, ultimately feeding the black hole in the centre of the Milky Way galaxy was studied, and also in the nucleus of the nearby galaxy IC342.

“The rich harvest of scientific results from this first observing campaign with SOFIA and the GREAT instrument only gives a first glimpse of the tremendous scientific potential of this observatory” states Jürgen Stutzki from Cologne University, co-investigator of the GREAT project. SOFIA will take advantage of rapid instrumental innovations, allowing instruments like GREAT to be continuously adapted to the newest technologies, and thus promises exciting astronomical observations for the coming years.

More information: Science from observations with GREAT during the Early Science phase, Astronomy Astrophysics, Volume 542, 10 May 2012

Provided by Max Planck Society (news : web)

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Article source: http://phys.org/news/2012-05-od-sh-molecules-space.html

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Macomb High, WIU grad to offer lecture on astronomy

By alkaon on April 26, 2012 No Comments

Astronomer and Macomb native Matthew Walker, Macomb High School class of 1994 and Western Illinois University class of 1999, will deliver a public lecture entitled “Dark Matter in Galaxies… for the Backyard Astronomer” at the Western Illinois Museum in Macomb, 201 S. Lafayette St., at 7:30 p.m. on Monday, April 30.  

Walker received his PhD degree in Astronomy Astrophysics from the University of Michigan in 2007. He worked as a postdoctoral researcher at the University of Cambridge, United Kingdom, from 2007 to 2010, and is now a research fellow at Harvard University in Cambridge, Mass.

In his presentation, Walker will summarize current research on the topic of dark matter — the nature of which remains one of astronomy’s enduring mysteries — and will include results from his own observations of the dwarf galaxies that orbit the Milky Way.  

The program will be geared for non-scientists. Anyone curious about the night sky is encouraged to attend. A question and answer period will follow. The doors open at 7:15 p.m. and light refreshments will be served.

Article source: http://www.mcdonoughvoice.com/newsnow/x596782036/Macomb-High-WIU-grad-to-offer-lecture-on-astronomy

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Astronomy: Portuguese astrophysicists reveal new data on the formation of …

By alkaon on April 15, 2012 No Comments

Astronomy: Portuguese astrophysicists reveal new data on the formation of extrasolar planets – CAUP

Posted on 14 April 2012. Tags: , , , , , , , ,

A team of astrophysicists from the Center of Astrophysics of the University of Porto (CAUP), in collaboration with the Observatory of the Geneva University, presented new data showing that the planetary orbits in a system are strongly aligned, like in a disk, just as we have in our own solar system.

Analyzing data from the spectrograph HARPS (ESO) and the Kepler satellite (NASA), the team of researchers, led by Pedro Figueira, simulated planetary systems to compare the differences in frequency of transiting systems.

Results show consistently that the “planets’ orbits are predominantly aligned, reinforcing the idea that planets form on a disk and suggesting for the first time that violent encounters between planets are not frequent.”

The study, which provides a very important clue about the formation and evolution of exoplanets, also shows that “the high degree of alignment of our system might well be the norm for planetary systems.”

Astrophysicist Pedro Figueira

According to Pedro Figueira, the first author of the study accepted for publication in the Astronomy Astrophysics online magazine, “These results show us that the way our solar system formed must be common. Its structure is the same as the other planetary systems we studied, buy viagra in united kingdom with all planets orbiting roughly in the same plane.”

Pedro Figueira , 29, is an advanced Post-doctoral student at CAUP. He has developed his research as part of the program “Origin and Evolution of Stars and Planets: Planetary Systems“,  which key objective is to address important issues of the physics that drives the formation and evolution of stars and planets.

The team of researchers is composed by P. Figueira (Centro de Astrofisica da Universidade do Porto), M. Marmier (Observatory of Geneva), G. Boue (Centro de Astrofisica da Universidade do Porto), C. Lovis (Observatory of Geneva), N. C. Santos (Centro de Astrofisica e Faculdade de Ciencias, Universidade do Porto), M. Montalto (Centro de Astrofisica da Universidade do Porto), S. Udry (Observatory of Geneva), F. Pepe (Observatory of Geneva), M. Mayor (Observatory of Geneva).

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Article source: http://portuguese-american-journal.com/astronomy-portuguese-astrophysicists-reveal-new-data-on-the-formation-of-extrasolar-planets-%E2%80%93-caup/

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Ultra-Compact Dwarf Galaxies Are Bright Star Clusters

By alkaon on December 19, 2011 No Comments

ScienceDaily (Dec. 19, 2011) — Astronomy Astrophysics is publishing the results of a detailed investigation of how many ‘ultra-compact dwarf galaxies’ (UCDs) can be found in nearby galaxy clusters. UCDs were recognized as a populous and potentially distinct class of stellar systems about a decade ago. But they are still mysterious objects that are characterized by a compact morphology (30-300 light-years in size) and high masses (more than one million solar masses).

More generally, their properties (e.g., their size, shape, or luminosity) are similar to those of both star clusters and dwarf galaxies. Several hundred UCDs have been found to date. Two main formation channels for these puzzling objects have been proposed so far. UCDs might either be very massive star clusters or be ‘normal’ dwarf galaxies transformed by tidal effects.

S. Mieske, M. Hilker, and I. Misgeld (ESO) present a statistical study of the UCD population: they define new statistical tools that relate the number of UCDs to the total luminosity of their host environment. This allows them to use statistical arguments to test the hypothesis that UCDs are bright star clusters. They predict that if UCDs are bright star clusters, we would expect to find only one or two UCDs around the Milky Way, which corresponds to what is seen, as omega Centauri is the only Milky Way satellite that can be considered a UCD.

With their new tools at hand, the authors have investigated the results of spectroscopic UCD surveys in the environment of massive galaxy clusters such as Fornax, Hydra, and Centaurus, as well as in galaxy groups like our very own Local Group. Most data analysed were obtained at ESO’s Very Large Telescope in Chile, using the instruments FLAMES, VIMOS, and FORS2. For the Fornax cluster, they also used a large database of compact stellar objects, which contained about 180 UCDs.

This statistical study clearly shows that the luminosity distribution of UCDs match very well that of the brightest globular star clusters. It supports the hypothesis that the vast majority of UCDs are actually very massive star clusters. From a statistical point of view, there is no need to invoke another scenario to explain the origin of UCDs.

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Journal Reference:

  1. S. Mieske, M. Hilker, I. Misgeld. The specific frequencies of ultra-compact dwarf galaxies. Astronomy Astrophysics, 2011; 537: A3 DOI: 10.1051/0004-6361/201117634

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Article source: http://www.sciencedaily.com/releases/2011/12/111219102052.htm

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Astronomers crack the Fried Egg Nebula

By alkaon on September 28, 2011 No Comments


Using the European Southern Observatory’s Very Large Telescope (VLT), teams from The University of Manchester, among others, took the new picture showing for the first time a huge dusty double shell surrounding the central hypergiant.


The star and its shells resemble an egg white around a yolky centre, leading the to nickname the object the Fried Egg . The international team’s results are published in the journal Astronomy Astrophysics.

The monster star, known to astronomers as IRAS 17163-3907, has a diameter about a thousand times bigger than our Sun. At a distance of about 13 000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500 000 times more brightly than the Sun.

The observations of the star and the discovery of its surrounding shells were made using the VISIR infrared camera on the VLT. The pictures are the first of this object to clearly show the material around it and reveal two almost perfectly spherical shells.

If the Fried Egg Nebula were placed in the centre of the Solar System, the Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface.

The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10 000 times the distance from the Earth to the Sun.

“This object was known to glow brightly in the infrared but, surprisingly, nobody had identified it as a yellow hypergiant before,” said Eric Lagadec (), who led the team that produced the new discovery.

Yellow hypergiants are in an extremely volatile phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and surrounded by gas.

Professor Albert Zijlstra, from The University of Manchester, said: “It is amazing that one of the brightest stars in the infrared sky had previously gone unnoticed. We are seeing a very rare event, when a star is beginning to blow off its outer layers, as a prelude to its final explosion as a supernova.”

This activity also shows that the star is likely to soon die an explosive death — it will be one of the next supernova explosions in our galaxy. Supernovae provide much-needed chemicals to the surrounding interstellar environment and the resulting shock waves can kick start the formation of new stars.

The Very Large mid-IR instrument, VISIR, captured this delicious image of the Fried Egg Nebula through three mid-infrared filters that are here coloured blue, green and red.

More information: “A double detached shell around a post-Red Supergiant: IRAS 17163-3907, the Fried Egg nebula“ by E. Lagadec et al., Astronomy Astrophysics.

Provided by University of Manchester (news : web)

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Article source: http://www.physorg.com/news/2011-09-astronomers-fried-egg-nebula.html

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Astronomy studies lined up for Darwen pubs

By alkaon on September 2, 2011 No Comments

Astronomy studies lined up for Darwen pubs

10:18am Friday 2nd September 2011

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    ROCKET-building and star-gazing sessions could soon be coming to pubs in Darwen thanks to a £24,000 grant.

    Two venues are already in discussions about hosting the nine-month Stars and Stuff project run by Erica Dobie and Adam Whittaker, of Beauty in the Universe.

    Church halls and community centres are also being approached.

    The pair were awarded the money by the Adult and Community Learning Fund to deliver practical astronomy education to adults and families in the town who are disengaged from traditional science
    institutions such as museums and universities.

    Stars and Stuff is devoted to astronomy, astrophysics and space exploration.

    Erica said: “A lot of traditional educational places are self-selecting.

    “You have to be interested already in science to go to a museum and have to make the effort.

    “With this, we’re bringing the science to people in a place where they already go and feel comfortable and relaxed.

    “Hopefully that will help them learn better.

    “The ultimate aim is to get people to take this on and go to university, but that can often seem very intimidating.

    “Anything we can do to soften that for people has got to be a good thing.”

    The sessions will be delivered by Adam with the help of Professor Ian Morison, of Gresham College, London.

    Food, childcare and transport will help participants attend.

    Geoff Russell, chief executive of the Skills Funding Agency, said: “It will make a tremendous difference to the lives of individuals and to their communities.”

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    Article source: http://www.lancashiretelegraph.co.uk/news/darwen/9230012.Astronomy_studies_lined_up_for_Darwen_pubs/

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    NASA Image of the day

    Pavlof Volcano From Station

     
    Astronauts aboard the International Space Station (ISS) photographed this striking view of Pavlof Volcano on May 18, 2013. The oblique perspective from the ISS reveals the three dimensional structure of the ash plume, which is often obscured by the top-down view of most remote sensing satellites. Situated in the Aleutian Arc about 625 miles (1,000 kilometers) southwest of Anchorage, Pavlof began erupting on May 13, 2013. The volcano jetted lava into the air and spewed an ash cloud 20,000 feet (6,000 meters) high. When photograph ISS036-E-2105 (top) was taken, the space station was about 475 miles south-southeast of the volcano (49.1° North latitude, 157.4° West longitude). The volcanic plume extended southeastward over the North Pacific Ocean. › Additional information/larger images. Image Credit: NASA
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