Really Rocket Science

It may not be a catchy name, but the ESO discovery is nevertheless very significant.

The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth’s. Combined with CoRoT-7b’s known radius, which is less than twice that of our terrestrial home, this tells us that the exoplanet’s density is quite similar to the Earth’s, suggesting a solid, rocky world. The extensive dataset also reveals the presence of another so-called super-Earth in this alien solar system.

The ESA’s P.R. folks put it in better pespective:

The confirmation of the nature of CoRoT-7b as the first rocky planet outside our Solar System marks a significant step forward in the search for Earth-like exoplanets. The detection by CoRoT and follow-up radial velocity measurements with HARPS suggest that this exoplanet, CoRoT-7b, has a density similar to that of Mercury, Venus, Mars and Earth making it only the fifth known terrestrial planet in the Universe.

The search for a habitable exoplanet is one of the holy grails in astronomy. One of the first steps towards this goal is the detection of terrestrial planets around solar-type stars. Dedicated programmes, using telescopes in space and on ground, have yielded evidence for hundreds of planets outside of our Solar System. The majority of these are giant, gaseous planets, but in recent years small, almost Earth-mass planets have been detected demonstrating that the discovery of Earth analogues – exoplanets with one Earth mass or one Earth radius orbiting a solar-type star at a distance of about 1 astronomical unit – is within reach.

 A little too hot for us. The work of astronomers continues, worldwide, day and night.

An optical image from the 0.6-m University of Michigan/CTIO Curtis Schmidt telescope of the brightest Radio Planetary Nebula in the Small Magellanic Cloud, JD 04. The inset box shows a portion of this image overlaid with radio contours from the Australia Telescope Compact Array. The planetary nebula is a glowing record of the final death throes of the star. (Optical images are courtesy of the Magellanic Cloud Emission Line Survey (MCELS) team).

The current Monthly Notices of the Royal Astronomical Society is reporting on super planetary nebulae, with University of Western Sydney Associate Professor Miroslav Filipovic going so far as to call them sexy in an interview with ABC:

Filipovic believes planetary nebula images are the most impressive objects in the galaxy.

"When you look at the Hubble pictures, they are the sexiest pictures you can find," he says.

According to Filipovic, it’s important to understand how super planetary nebulae form, particularly as they represent the fate of our Sun.

"This is something that will happen to us in about five billion years from now," he says.

Get a load of the abstract:

We report the extragalactic radio-continuum detection of 15 planetary nebulae (PNe) in the Magellanic Clouds (MCs) from recent Australia Telescope Compact Array+Parkes mosaic surveys. These detections were supplemented by new and high-resolution radio, optical and infrared observations which helped to resolve the true nature of the objects. Four of the PNe are located in the Small Magellanic Cloud (SMC) and 11 are located in the Large Magellanic Cloud (LMC). Based on Galactic PNe the expected radio flux densities at the distance of the LMC/SMC are up to ∼2.5 and ∼2.0 mJy at 1.4 GHz, respectively. We find that one of our new radio PNe in the SMC has a flux density of 5.1 mJy at 1.4 GHz, several times higher than expected. We suggest that the most luminous radio PN in the SMC (N S68) may represent the upper limit to radio-peak luminosity because it is approximately three times more luminous than NGC 7027, the most luminous known Galactic PN. We note that the optical diameters of these 15 Magellanic Clouds (MCs) PNe vary from very small (∼0.08 pc or 0.32 arcsec; SMP L47) to very large (∼1 pc or 4 arcsec; SMP L83). Their flux densities peak at different frequencies, suggesting that they may be in different stages of evolution. We briefly discuss mechanisms that may explain their unusually high radio-continuum flux densities. We argue that these detections may help solve the ‘missing mass problem’ in PNe whose central stars were originally  1–8 M_⊙ . We explore the possible link between ionized haloes ejected by the central stars in their late evolution and extended radio emission. Because of their higher than expected flux densities, we tentatively call this PNe (sub)sample –’Super PNe’.

Sexy indeed.

Great shot by Thierry Legault, using special solar filters, of the ISS and shuttle, silhouetted against the Sun. Via OnOrbit

Today’s news in Asia is about the total solar eclipse, the longest of the century:

The path of the Moon’s umbral shadow begins in India and crosses through Nepal, Bangladesh, Bhutan, Myanmar and China. After leaving mainland Asia, the path crosses Japan’s Ryukyu Islands and curves southeast through the Pacific Ocean where the maximum duration of totality reaches 6 min 39 s. A partial eclipse is seen within the much broader path of the Moon’s penumbral shadow, which includes most of eastern Asia, Indonesia, and the Pacific Ocean.

Check out Xinhua’s photo gallery, and, if you can bear it, this TV news report…

Tommy Chong of Cheech & Chong said it best: "Far out, man!"

I wonder if somebody at NASA’s Goddard Space Flight Center said something similar about this blast from the past, maybe 13 billion light years away:

NASA’s Swift satellite and an international team of astronomers have found a gamma-ray burst from a star that died when the universe was only 630 million years old, or less than five percent of its present age. The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen.

"Swift was designed to catch these very distant bursts," said Swift lead scientist Neil Gehrels at NASA’s Goddard Space Flight Center in Greenbelt, Md. "The incredible distance to this burst exceeded our greatest expectations — it was a true blast from the past."

At 3:55 a.m. EDT on April 23, Swift detected a ten-second-long gamma-ray burst of modest brightness. It quickly pivoted to bring its ultraviolet/optical and X-ray telescopes to observe the burst location. Swift saw a fading X-ray afterglow but none in visible light.

"The burst most likely arose from the explosion of a massive star," said Derek Fox at Pennsylvania State University. "We’re seeing the demise of a star — and probably the birth of a black hole — in one of the universe’s earliest stellar generations."

Gamma-ray bursts are the universe’s most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets — driven by processes not fully understood — punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates short-lived afterglows in many wavelengths.

"The lack of visible light alone suggested this could be a very distant object," explained team member Edo Berger of Harvard University.

Beyond a certain distance, the expansion of the universe shifts all optical emission into longer infrared wavelengths. While a star’s ultraviolet light could be similarly shifted into the visible region, ultraviolet-absorbing hydrogen gas grows thicker at earlier times. "If you look far enough away, you can’t see visible light from any object," he noted.

Within three hours of the burst, Nial Tanvir at the University of Leicester, U.K., and his colleagues reported detection of an infrared source at the Swift position using the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. "Burst afterglows provide us with the most information about the exploded star and its environs," Tanvir said. "But because afterglows fade out so fast, we must target them quickly."

At the same time, Fox led an effort to obtain infrared images of the afterglow using the Gemini North Telescope on Mauna Kea. The source appeared in longer-wavelength images but was absent in an image taken at the shortest wavelength of 1 micron. This "drop out" corresponded to a distance of about 13 billion light-years.

Here’s a video of what a gamma ray burst would look like up-close (Credit: NASA/Swift/Cruz deWild):

 Nice set of pics from Hubble:

The NASA/ESA’s Hubble Space Telescope has captured this image of NGC 7049, a mysterious looking galaxy on the border between spiral and elliptical galaxies. NGC 7049 is found in the constellation of Indus, and is the brightest of a cluster of galaxies, a so-called Brightest Cluster Galaxy (BCG). Typical BCGs are some of the oldest and most massive galaxies. They provide excellent opportunities for astronomers to study the elusive globular clusters lurking within.

The globular clusters in NGC 7049 are seen as the sprinkling of small faint points of light in the galaxy’s halo. The halo – the ghostly region of diffuse light surrounding the galaxy – is composed of myriads of individual stars and provides a luminous background to the remarkable swirling ring of dust lanes surrounding NGC 7049’s core. Globular clusters are very dense and compact groupings of a few hundreds of thousands of stars bound together by gravity. They contain some of the first stars to be produced in a galaxy. NGC 7049 has far fewer such clusters than other similar giant galaxies in very big, rich groups. This indicates to astronomers how the surrounding environment influenced the formation of galaxy halos in the early Universe.

The image was taken by the Advanced Camera for Surveys on Hubble, which is optimised to hunt for galaxies and galaxy clusters in the remote and ancient Universe, at a time when our cosmos was very young.

Twisting waves of the Sun’s corona can help us understand solar weather, via PhysOrg:

The massive solar twists, known as Alfvén waves, were discovered in the lower atmosphere with the Swedish Solar Telescope in the Canary Islands by scientists from Queen’s University Belfast, the University of Sheffield and California State University Northridge.

The increase in solar temperature from approximately 6000 degrees on the visible surface of the Sun (photosphere) to well over a million degrees in the higher overlaying solar corona, has remained at the forefront of astrophysical research for over half a century. The new observations reveal the process behind this phenomenon, whereby these unique magnetic oscillations spread upward from the solar surface to the Sun’s corona with an average speed of over 20km per second, carrying enough energy to heat the plasma to well over a few million degrees.

Prof. Mathioudakis, the leader of the Queen’s University Belfast Solar Group, said, "Understanding solar activity and its influence on the Earth’s climate is of paramount importance for human kind. The Sun is not as quiet as many people think. The solar corona, visible from Earth only during a total solar eclipse, is a very dynamic environment which can erupt suddenly, releasing more energy than 10 billion atomic bombs. Our study makes a major advancement in the understanding of how the million-degree corona manages to achieve this feat."

Alfvén waves are caused by the twisting of structures in the Sun’s atmosphere and can be detected by the periodic velocity signals emitted. The Alfvén waves detected in this study were found to be associated with a large magnetic field concentration on the surface of the Sun, approximately twice the size of the British Isles. These strong magnetic fields manifest as bright features, often with lifetimes exceeding one hour. The Swedish Solar Telescope is the largest solar telescope in Europe and produces some of the sharpest images currently available. Bearing in mind that the Sun is 150 million kilometres away, the measurements carried out are equivalent to reading the time on Big Ben in London from Tokyo.

Comet Lulin‘s closest approach to Earth is today:

The comet makes its closest approach to Earth (0.41 AU) on Feb. 24, 2009. Current estimates peg the maximum brightness at 4th or 5th magnitude, which means dark country skies would be required to see it. No one can say for sure, however, because this appears to be Lulin’s first visit to the inner solar system and its first exposure to intense sunlight. Surprises are possible.

Lulin’s green color comes from the gases that make up its Jupiter-sized atmosphere. Jets spewing from the comet’s nucleus contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C2). Both substances glow green when illuminated by sunlight in the near-vacuum of space.

Can’t get out or can’t see? No worries: Gregg Ruppel of St. Louis has some great images.

No, not your own fireworks — playing with chemistry at home is dangerous. We’re talking dazzling astronomic observation, as this "image of the day" from NASA:

Stars and a Stripe in Celestial Fireworks

A delicate ribbon of gas floats eerily in our galaxy. A contrail from an alien spaceship? A jet from a black-hole? Actually this image, taken by NASA’s Hubble Space Telescope, is a very thin section of a supernova remnant caused by a stellar explosion that occurred more than 1,000 years ago.

Around May 1, 1006 A.D., observers from Africa to Europe to the Far East witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star nearly 7,000 light-years away. The supernova was probably the brightest star ever seen by humans, and surpassed Venus as the brightest object in the night time sky, only to be surpassed by the moon. It was visible even during the day for weeks, and remained visible to the naked eye for at least two and a half years before fading away.

It wasn’t until the mid-1960s that radio astronomers first detected a nearly circular ring of material at the recorded position of the supernova. The ring was almost 30 arcminutes across, the same angular diameter as the full moon. The size of the remnant implied that the blast wave from the supernova had expanded at nearly 20 million miles per hour over the nearly 1,000 years since the explosion occurred.

Today, SN 1006 has a diameter of nearly 60 light-years, and it is still expanding at roughly 6 million miles per hour. Even at this tremendous speed, however, it takes observations typically separated by years to see significant outward motion of the shock wave against the grid of background stars. In the Hubble image as displayed, the supernova would have occurred far off the lower right corner of the image, and the motion would be toward the upper left.

Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) 

But NASA is predicting a planetary alignment for today and this weekend, via PhysOrg.com:

The show gets going on Friday, July 4th. Red Mars and ringed Saturn converge just to the left of the bright star Regulus. The three lights make a pretty 1st-magnitude line in the heavens.

But that is just the beginning. On Saturday, July 5th, with weekend fireworks at fever pitch, a lovely crescent Moon joins the show. Saturn, Mars, and the Moon trace an even brighter line than the night before.

Scan a small telescope along the line. You’ll see Saturn’s rings, the little red disk of Mars, a grand sweep of lunar mountains and craters, and just maybe—flash!—a manmade incendiary. How often do you see fireworks through a telescope?

This is, however, more than just a flashy gathering of planets—it is also a gathering of spaceships and robots.

Each of the three worlds is orbited or inhabited by probes from Earth. Saturn has the Cassini spacecraft, studying the gas giant’s storms, moons and rings. The Moon has two probes in orbit: Kaguya from Japan and Chang’e-1 from China. The pair, operating independently, are mapping the Moon and scanning for resources in advance of future human landings. NASA’s Lunar Reconnaissance Orbiter will join them later this year.

Mars has more probes than the others combined. Three active satellites orbit the red planet: Europe’s Mars Express and NASA’s Mars Odyssey and Mars Reconnaissance Orbiter. The three not only study Mars with their own instruments, but also form a satellite network in support of NASA’s Mars rovers Spirit and Opportunity and Mars lander Phoenix.

None of these mechanical specks are visible in a backyard telescope, but they are there, heralds of a growing human presence in the solar system. Tell that to your buddy at the fireworks show!

During the short night of July 5th, the Moon glides past Mars and Saturn so that nightfall on Sunday, July 6th, brings a different arrangement—a scalene triangle. The triad is easy to find in the hours after sunset. Look west and let the Moon be your guide.

In the nights that follow, the Moon exits stage left, leaving the others behind. Don’t stop watching, though. Saturn and Mars are converging for their closest encounter of the next 14 years. After nightfall on Thursday, July 10th, the two planets will be just ¾ of a degree apart, snug enough to fit behind the tip of your pinky finger held at arm’s length.

Now that’s spectacular—no fireworks required.

Cool. No smoke, fire or noise. There’s more than enough of that going on around you. To all the rocket scientist in the U.S., have a great 4th of July. 

Just how common are Earth-like planets in the universe?

About five times more common than previously thought, according to European researchers presenting their latest findings at a conference in France today:

European astronomers on Monday said they had located dozens of giant planets in three distant solar systems.

The discovery suggests that at least one third of stars similar to our own Sun harbour such planets, multiplying previous estimates by five.

A trio of these ‘super-Earths’ — so-called because they are several times the mass of our own planet — were detected orbiting a star known as HD 40307 some 42 lights away.

Reuters has additional details: 

The [three] planets are bigger than Earth — one is 4.2 times the mass, one is 6.7 times and the third is 9.4 times.

They orbit their star at extremely rapid speeds — one whizzing around in just four days, compared with Earth’s 365 days, one taking 10 days and the slowest taking 20 days.

The first planet outside our solar system was detected in 1995, and less than 280 of these exoplanets had been found before today’s unveiling of 45 new exoplanet discoveries.

The astronomers used the High Accuracy Radial velocity Planet Searcher— or HARPS — to spot the planets. The next-generation HARPS spectrograph is used in conjunction with the 3.6-m telescope at La Silla observatory in Chile: 

La Silla is a 2400-m mountain, bordering the southern extremity of the Atacama desert in Chile. It is located about 160 Km north of La Serena. Its geographical coordinates are: Latitude 29º 15′ south & Longitude 70º 44′ west.

Originally known as Cinchado, the mountain was renamed La Silla (the saddle) after its shape. It rises quite isolated and remote from any artificial light and dust sources (astronomy’s worst enemies). La Silla was the first ESO observatory built in Chile. 

The ESO press release also has additional information on these exciting, extra-solar discoveries.