20
Jan 10

Comet might result of a collision between asteroids

Source: Skymania

Astronomers are watching what they believe is a remarkable collision between two asteroids deep in space. If they are right, it is the first time a high-speed crash has ever been witnessed between massive space rocks.

The cosmic hit-and-run is happening 250 million miles away in a band of debris lying between planets Mars and Jupiter - the main asteroid belt.

An automatic sky camera called LINEAR in New Mexico snapped a newly discovered object there that looks fuzzy with a tail like a comet rather than a dot of light like a normal asteroid. It has been labelled P/2010 A2.(read more)

Related Links:
Skymania
Sky and Telescope
Universe Today
Discovery News

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
19
Jan 10

Herschel readies itself for the Orion Nebula

Source: ESA


The Orion Nebula. Credit: NASA, ESA, M. Robberto (STScI/ESA) and
The Hubble Space Telescope Orion Treasury Project Team

ESA's Herschel observatory is back to full operation following the reactivation of its HiFi instrument. HiFi, having been offline for 160 days while engineers investigated an unexpected problem in the electronic system, is now perfectly placed to resume its study of forming stars and planets.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
19
Jan 10

Watching the Moon

This is an excellent week to follow the moon as it travels across the sky, if you take a look at its shape and position over a number of nights (to the end of the week for example), you should notice some interesting changes. Here's what you need to do:

Take a look at the moon at the same time each evening (between 8pm and 9pm would be good) and note the following:

  • The shape or form of the moon
  • The position of the moon in the sky (high, low, above a tree or a building, etc)
  • The position of the moon with regards to nearby stars (to the left/right of a bright star, between two bright stars, etc.

When you've done that over a week you should be able to distinguish between the "apparent" motion of the moon and the "proper" motion of the moon, but we'll discuss that at the end of the week.

Photo credit: Bob Larcher (photo taken with a digital camera "hand-held" in front of the eye piece of an 8 inch reflector

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
19
Jan 10

Watching the Moon

This is an excellent week to follow the moon as it travels across the sky, if you take a look at its shape and position over a number of nights (to the end of the week for example), you should notice some interesting changes. Here's what you need to do:

Take a look at the moon at the same time each evening (between 8pm and 9pm would be good) and note the following:

  • The shape or form of the moon
  • The position of the moon in the sky (high, low, above a tree or a building, etc)
  • The position of the moon with regards to nearby stars (to the left/right of a bright star, between two bright stars, etc.

When you've done that over a week you should be able to distinguish between the "apparent" motion of the moon and the "proper" motion of the moon, but we'll discuss that at the end of the week.

Photo credit: Bob Larcher (photo taken with a digital camera "hand-held" in front of the eye piece of an 8 inch reflector

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
19
Jan 10

Tooling up ExoMars

Source: ESA


Artist's impression of the ExoMars Trace Gas Orbiter. Credits: ESA

ESA and NASA are inviting scientists from across the world to propose instruments for their joint Mars mission, the ExoMars Trace Gas Orbiter. Scheduled for launch in 2016, the spacecraft will focus on understanding the rarest constituents of the martian atmosphere, including the mysterious methane that could signal life on Mars.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
18
Jan 10

Star colours

Did you get to take a look at the stars? Here's what you should have seen, Betelgeuse (top left of Orion) is a reddish star, Rigel (bottom right of Orion) is a bluish star, Aldeberan (found by the following the imaginary line through the "belt" upwards to the right) has a distinct orange tint to it and Sirius (found by the following the imaginary line through the "belt" downwards to the left) is white - yes there are white stars! There are also yellow stars, green stars and stars of almost all the colours of the rainbow!

So why are stars different colours? In short it's linked to their temperature, blue and white stars being extremely hot and red and orange being somewhat cooler, although still very hot!

If you would like to know more about the colours, temperatures and sizes of stars, take a look here: http://en.wikipedia.org/wiki/Star

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
18
Jan 10

Star colours

Did you get to take a look at the stars? Here's what you should have seen, Betelgeuse (top left of Orion) is a reddish star, Rigel (bottom right of Orion) is a bluish star, Aldeberan (found by the following the imaginary line through the "belt" upwards to the right) has a distinct orange tint to it and Sirius (found by the following the imaginary line through the "belt" downwards to the left) is white - yes there are white stars! There are also yellow stars, green stars and stars of almost all the colours of the rainbow!

So why are stars different colours? In short it's linked to their temperature, blue and white stars being extremely hot and red and orange being somewhat cooler, although still very hot!

If you would like to know more about the colours, temperatures and sizes of stars, take a look here: http://en.wikipedia.org/wiki/Star

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
17
Jan 10

MRO/HiRISE Studies of Mars

Source: HiRISE

Martian landforms shaped by winds, water, lava flow, seasonal icing and other forces are analyzed in 21 journal reports based on data from a camera orbiting Mars.

Juventae Chasma in the Valles Marineris region of Mars.
Credit: NASA/JPL-Caltech/University of Arizona

The research in a January special issue of Icarus testifies to the diversity of the planet being examined by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. (read more)

Links:
Icarus -Volume 205, Issue 1, Pages 1-320 (January 2010)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
17
Jan 10

Chemical similarities between Galactic bulge and local thick disk red giants

Source: arXiv:1001.2521v1

The formation and evolution of the Galactic bulge and its relationship with the other Galactic populations is still poorly understood.

To establish the chemical differences and similarities between the bulge and other stellar populations, the astronomers have performed elemental abundance analysis of oxygen, magnesium, silicon, calcium, titanium, sodium and aluminium of red giant stars in the bulge as well as of local thin disk, thick disk and halo giants (see figure).

The stellar populations of the Galaxy can be distinguished as being part of the bulge, of thin disk, , of thick disk and halo giants.
1) The image on the left, of the galaxy NGC 4526, gives a visual perception of galactic structure. Credit: NASA.
2) The image on the right presents schematically the galactic structure.

The authors used high-resolution optical spectra of 25 bulge giants in Baade’s window and made a comparison with 55 giants (4 halo, 29 thin disk and 22 thick disk giants) in the solar neighbourhood.

Baade's Window is named after the German astronomer Walter Baade and lies towards the constellation of Sagittarius. This region has relatively low amounts of interstellar "dust" along our line of sight and is a "window" because in this direction we are able to see all the way to the Milky Way Galactic Center and beyond. Therefore it is used to inspect distant stars and to determine the internal geometry of the Milky Way. Using bulge giants and giants in our neighbourhood the authors could compare the inner structure of the Galaxy with our vicinity.

The authors have found that all stars have similar stellar parameters but cover a broad range in metallicity. In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. Since stars, which comprise most of the visible matter in the universe, are composed mostly of hydrogen and helium, astronomers, for convenience's sake, use the blanket term "metal" to describe all other elements collectively.

The team of astronomers was able to confirm the well-established differences for [α /Fe] at a given metallicity between the local thin and thick disks. For all the elements investigated, they found no chemical distinction between the bulge and the local thick disk.

Their findings lead to the conclusion that the bulge and local thick disk stars experienced similar formation timescales, star formation rates and initial mass functions. The scientific team thinks that the identical types of stars that can be found on the thick disk and bulge stars may reflect a rapid chemical evolution taking place before the bulge and thick disk structures we see today were formed, or it may reflect Galactic orbital migration of inner disk/bulge stars resulting in stars in the solar neighbourhood with thick-disk kinematics.

This reasearch was accepted for publication byAstronomy & Astrophysics.(read more)

Links:
Original paper:Alves-Brito,A., Melendez,J., Asplund,M., Ramirez,I., Yong,D. (2010) Chemical similarities between Galactic bulge and local thick disk red giants: O, Na, Mg, Al, Si, Ca and Ti, Astronomy & Astrophysics, in press.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
16
Jan 10

What colour are stars?

If you asked someone what colour stars are, they would probably say white, and they wouldn't be wrong; however, not all stars are white.

Go and take a look at the stars we have been talking about in previous postings; Betelgeuse (top left of Orion), Rigel (bottom right of Orion), Aldeberan (found by the following the imaginary line through the "belt" upwards to the right) and Sirius (found by the following the imaginary line through the "belt" downwards to the left).

Take a good careful look at these stars and in the next posting we'll talk about theirs colours!

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
16
Jan 10

What's the colour of the stars?

If you asked someone what is the colour of the stars, they would probably say white; they wouldn't be completely wrong; however, not all stars are white.

Go and take a look at the stars we have been talking about in previous posts; Betelgeuse (top left of Orion), Rigel (bottom right of Orion), Aldeberan (found by the following the imaginary line through the "belt" upwards to the right) and Sirius (found by the following the imaginary line through the "belt" downwards to the left).

Take a good careful look at these stars and in a future post we'll talk about their colours!

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
16
Jan 10

Annular Eclipse on Southeastern Countries

Source: Wikipedia

On January 15th there was an annular eclipse, but it wasn't visible from the majority of the European territories.


Cropped image of full annular solar eclipse as seen in Bangui, Central African Republic at 05:19:04 GMT (6:19 a.m. local time). The bottom 'noise' are clouds. Source: Wikimedia; Author: Tino Kreutzer.

The eclipse was visible as only partial eclipse in much of Africa, Eastern Europe, the Middle East and Asia. It was seen as annular eclipse within a narrow stretch of 300 km (190 mi) width across Central Africa, Maldives, South Kerala (India), South Tamil Nadu (India), Sri Lanka and parts of Bangladesh, Burma and China.

This was the longest annular solar eclipse of the millennium, with a maximum length of 11 mins and 7.8 seconds.

The next eclipse that will be longer than this one will occur on December 23rd, 3043. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

The quest for Extragalactic Exoplanets begins...

Source: arXiv:1001.2105v1

While the most distant exoplanets detected until today are OGLE-05-390L b, MOA-2007-BLG-400-L b at around 6,500 & 6,000 parsecs, which  roughly means ~21,190 & ~19,500 light-years away respectively, an international team of astronomers proposes  a new observational method that they believe will allow  the detection of exoplanets in the Andromeda galaxy (M31) that is at a distance of 2.9 million light-years from us.


A simulation of the expected microlensing event. Credit: Ingrosso et al. (2009)

The authors think that that exoplanets in the M31 galaxy may be detected with the pixel-lensing method by using telescopes making high cadence observations of an ongoing microlensing event.Although the mean mass for detectable exoplanets is about 2 MJ, even small mass exoplanets (inferior to 20 Earth masses) can cause significant deviations, which are observable with large telescopes. (read more)

Link:

Ingrosso,G., De Paolis,F., Novati,S.C., Jetzer,Ph.,  Nucita,A.A., Zakharov,A. F. (2009). Detection of Exoplanets in M31 with Pixel-Lensing: The Event Pa-99-N2 Case, in proceedings of the "Twelfth Marcel Grosmann Meeting", Paris.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

Celebrating the fifth anniversary of Huygens' Titan touchdown

Source: ESA General


Composite of Huygens DISR images shows patterns of drainage, flow and erosion in the Huygens landing site region. Credits: ESA/NASA/JPL/University of Arizona

Five years ago today, ESA's Huygens probe descended to the surface of Titan, Saturn's largest moon. Today planetary scientists from around the world have gathered in Barcelona to discuss the legacy of Huygens and to consider future Titan exploration missions.(read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

Finding Galaxy Clusters at redshift ~1.8

Source: arXiv:1001.2232v1


RGB “color” images of one of the three candidate clusters around COSMOS-FR I 03 . The image was obtained using Spitzer 3.6μm, Subaru r and B band images for the R, G and B channels respectively. White circles indicate objects with 1.6 < zphot < 2.3. The projected size of the fields are 18000 × 18000 (~ 1.5 × 1.5 Mpc2 at z ~ 1.8), North is up.
Credit: COSMOS team.

A team of astronomers from several organizations presented three candidate clusters of galaxies at redshifts between 1.7 and 2.0, which corresponds to a fundamentally unexplored epoch of clusters evolution. The candidates were found by studying the environment around our newly selected sample of “beacons” low-luminosity (FR I) radio galaxies. Detection of galaxy clusters from this epoch doesn't have a completely convincing method and the search for clusters of galaxies at z > 1 has proven to be particularly difficult, mainly because of the reduced contrast between cluster members and field galaxies.

The team has now proposed a method that seems suitable to make detections of these galaxy clusters. (read more)

The article in arXiv:
Chiaberge, M., Capetti,A., Macchetto,D., Rosati,P., Tozzi, P., Tremblay,P.R. (2010).Three candidate clusters of galaxies at redshift ~1.8: The missing link between protoclusters and local clusters?,Accepted for publication in ApJL.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

Asteroid 2010 AL30 passes close to Earth

Source: Space Weather

Is it an asteroid or a derelict spacecraft? Mystery object 2010 AL30 is flew past Earth last night only 1/3rd the distance to the Moon, and telescopes around the world were watching.


2010 AL30 is the faint object that comes down to the right.
This image was made in Colombia, using a 14-inch Meade LX200.
Credit: Alberto Quijano Vodniza (Amateur Astronomer)

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

Formation of Dwarf Galaxies explained

Source: University of Washington


These images depict various stages of galaxy formation under the cold dark
matter theory using new computer simulations that account for the effects
of supernova explosions. Credit: Katy Brooks

For more than two decades, the cold dark matter theory has been used by cosmologists to explain how the smooth universe born in the big bang more than 13 billion years ago evolved into the filamentary, galaxy-rich cosmic web that we see today.

There's been just one problem: The theory suggested most galaxies should have far more stars and dark matter at their cores than they actually do. The problem is most pronounced for dwarf galaxies, the most common galaxies in our own celestial neighborhood. Each contains less than 1 percent of the stars found in large galaxies such as the Milky Way.

Now an international research team, led by a UW astronomer, reports in the Jan. 14 issue of Nature that it resolved the problem using millions of hours on supercomputers to run simulations of galaxy formation (1 million hours is more than 100 years). The simulations produced dwarf galaxies very much like those observed today by satellites and large telescopes around the world. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
14
Jan 10

UI astronomers capture first-of-kind image at distant star

Source: University of Iowa

Image: Composite image of a large radio coronal loop superimposed on an artist's conception of Algol, a binary star system. Credit: William Peterson.

Two University of Iowa researchers have made the first direct radio image of a coronal loop at a star, other than the sun, thereby providing scientists with information that may lead to a better understanding of how such phenomena as space weather affect the Earth. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
13
Jan 10

Formation of massive planets in binary star systems

Source: arXiv


Sunset on a planet of a binary system. Credit:NASA.

Over the last years 40 planetary systems have been discovered surounding binary star systems. In all cases the configuration appears to be circumstellar, where the planets orbit around one of the stars, the secondary acting as a disturber. This could have happened in our own solar system if Jupiter was much bigger than it actually is.

The formation of planets in the binary star systems is more difficult than around single stars due to the gravitational action of the companion on the dynamics of the protoplanetary disk. Wiley Kley has presented relevant observational evidence that planets can really exist in in binary systems. (read more)

Link:

arXiv-Kley, W.(2009) Extrasolar Planets in Multi-body Systems: Theory and Observations, Editors: K. Gozdziewski, A. Niedzielski and J. Schneider, EAS Publications Series.

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon
13
Jan 10

VLT Captures First Direct Spectrum of an Exoplanet

Source: ESO Science Release 02/10

ESO has just released the magnificent information that the VLT has been capable, for the first time in human, to provide data that allows the study of an exoplanet's atmosphere.

By studying a triple planetary system that resembles a scaled-up version of our own Sun’s family of planets, astronomers have been able to obtain the first direct spectrum — the “chemical fingerprint” — of a planet orbiting a distant star, thus bringing new insights into the planet's formation and composition. The result represents a milestone in the search for life elsewhere in the Universe. (read more)

Twitter del.icio.us Digg Facebook linked-in Yahoo Buzz StumbleUpon