Really Rocket Science

Located 20.5 light years away (123 trillion miles), Gliese 581g has a 100% chance of sustaining life. The planet is located in the “Goldilocks” zone, which is considered habitable. If you used a rocket traveling at 1/10 the speed of light (19,000 MPH), it would take 200 years to get there — who has time for that, Dave?

It was announced in September:

A team of planet hunters from the University of California (UC) Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of a planet with three times the mass of Earth orbiting a nearby star at a distance that places it squarely in the middle of the star’s “habitable zone.”

This discovery was the result of more than a decade of observations using the W. M. Keck Observatory in Hawaii, one of the world’s largest optical telescopes. The research, sponsored by NASA and the National Science Foundation, placed the planet in an area where liquid water could exist on the planet’s surface. If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one.

To astronomers, a “potentially habitable” planet is one that could sustain life, not necessarily one where humans would thrive. Habitability depends on many factors, but having liquid water and an atmosphere are among the most important.

The new findings are based on 11 years of observations of the nearby red dwarf star Gliese 581 using the HIRES spectrometer on the Keck I Telescope. The spectrometer allows precise measurements of a star’s radial velocity (its motion along the line of sight from Earth), which can reveal the presence of planets. The gravitational tug of an orbiting planet causes periodic changes in the radial velocity of the host star. Multiple planets induce complex wobbles in the star’s motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses.

Washington State’s Dirk Schulze-Makuch has a group of scientists working on it.

I like pulsars and I love how our friends at NASA GSFC explain it — with animation.

An international team of scientists using NASA’s Fermi Gamma-ray Space Telescope has discovered a surprisingly powerful millisecond pulsar that challenges existing theories about how these objects form.

At the same time, another team has located nine new gamma-ray pulsars in Fermi data, using improved analytical techniques.

A pulsar is a type of neutron star that emits electromagnetic energy at periodic intervals. A neutron star is the closest thing to a black hole that astronomers can observe directly, crushing half a million times more mass than Earth into a sphere no larger than a city. This matter is so compressed that even a teaspoonful weighs as much as Mount Everest.

“With this new batch of pulsars, Fermi now has detected more than 100, which is an exciting milestone when you consider that, before Fermi’s launch in 2008, only seven of them were known to emit gamma rays,” said Pablo Saz Parkinson, an astrophysicist at the Santa Cruz Institute for Particle Physics at the University of California Santa Cruz, and a co-author on two papers detailing the findings.

One group of pulsars combines incredible density with extreme rotation. The fastest of these so-called millisecond pulsars whirls at 43,000 revolutions per minute.

Millisecond pulsars are thought to achieve such speeds because they are gravitationally bound in binary systems with normal stars. During part of their stellar lives, gas flows from the normal star to the pulsar. Over time, the impact of this falling gas gradually spins up the pulsar’s rotation.

The strong magnetic fields and rapid rotation of pulsars cause them to emit powerful beams of energy, from radio waves to gamma rays. Because the star is transferring rotational energy to the pulsar, the pulsar’s spin slows after this transfer is completed.

Typically, millisecond pulsars are around a billion years old. However, in the Nov. 3 issue of Science, the Fermi team reveals a bright, energetic millisecond pulsar only 25 million years old.

The object, named PSR J1823−3021A, lies within NGC 6624, a spherical collection of ancient stars called a globular cluster, one of about 160 similar objects that orbit our galaxy. The cluster is about 10 billion years old and lies about 27,000 light-years away toward the constellation Sagittarius.

Fermi’s Large Area Telescope (LAT) showed that eleven globular clusters emit gamma rays, the cumulative emission of dozens of millisecond pulsars too faint for even Fermi to detect individually. But that’s not the case for NGC 6624.

“It’s amazing that all of the gamma rays we see from this cluster are coming from a single object. It must have formed recently based on how rapidly it’s emitting energy. It’s a bit like finding a screaming baby in a quiet retirement home,” said Paulo Freire, the study’s lead author, at the Max Planck Institute for Radio Astronomy in Bonn, Germany.

J1823−3021A was previously identified as a pulsar by its radio emission, yet of the nine new pulsars, none are millisecond pulsars, and only one was later found to emit radio waves.

Despite its sensitivity, Fermi’s LAT may detect only one gamma ray for every 100,000 rotations of some of these faint pulsars. Yet new analysis techniques applied to the precise position and arrival time of photons collected by the LAT since 2008 were able to identify them.

“We adapted methods originally devised for studying gravitational waves to the problem of finding gamma-ray pulsars, and we were quickly rewarded,” said Bruce Allen, director of the Max Planck Institute for Gravitational Physics in Hannover, Germany. Allen co-authored a paper on the discoveries that was published online today in The Astrophysical Journal.

Great work by astronomers Adam Kraus (University of Hawaii Institute for Astronomy) and Michael Ireland (Macquarie University and the Australian Astronomical Observatory) in finding the youngest planet ever.

“LkCa 15 b is the youngest planet ever found, about 5 times younger than the previous record holder,” said Kraus. “This young gas giant is being built out of the dust and gas. In the past, you couldn’t measure this kind of phenomenon because it’s happening so close to the star. But, for the first time, we’ve been able to directly measure the planet itself as well as the dusty matter around it.”

Kraus will be presenting the discovery at an Oct. 19 meeting at NASA’s Goddard Space Flight Center. The meeting follows the acceptance of a research paper on the discovery by Kraus and Ireland by The Astrophysical Journal.

The optical sleight of hand used by the astronomers is to combine the power of Keck’s Adaptive Optics with a technique called aperture mask interferometry. The former is the use of a deformable mirror to rapidly correct for atmospheric distortions of starlight. The latter involves placing a small mask with several holes in the path of the light collected and concentrated by a giant telescope. With that, the scientists can manipulate the light waves.

“It’s like we have an array of small mirrors,” said Kraus. “We can manipulate the light and cancel out distortions.” The technique allows the astronomers to cancel out the bright light of stars. They can then resolve disks of dust around stars and see gaps in the dusty layers where protoplanets may be hiding.

“Interferometry has actually been around since the 1800s, but through the use of adaptive optics has only been able to reach nearby young suns for about the last 7 years.” said Dr. Ireland. “Since then we’ve been trying to push the technique to its limits using the biggest telescopes in the world, especially Keck.”

The discovery of LkCa 15 b began as a survey of 150 young dusty stars in star-forming regions. That led to the more concentrated study of a dozen stars.

“LkCa 15 was only our second target, and we immediately knew we were seeing something new,” said Kraus. “We could see a faint point source near the star, so thinking it might be a Jupiter-like planet we went back a year later to get more data.”

In further investigations at varying wavelengths, the astronomers were intrigued to discover that the phenomenon was more complex than a single companion object.

“We realized we had uncovered a super Jupiter-sized gas planet, but that we could also measure the dust and gas surrounding it. We’d found a planet at its very beginning” said Kraus.

Drs. Kraus and Ireland plan to continue their observations of LkCa 15 and other nearby young stars in their efforts to construct a clearer picture of how planets and solar systems form.

Mirrors. Go figure.

Want to know how this was done? Get the details.

WTF is HUDF? Hubble Ultra Deep Field, KWIM?

It’s the deepest ever. Seriously:

The Hubble Ultra-Deep Field (HUDF) is an image of a small region of space in the constellation Fornax, composited from Hubble Space Telescope data accumulated over a period from September 24, 2003, through to January 16, 2004. It is the deepest image of the universe ever taken,[1] looking back approximately 13 billion years (between 400 and 800 million years after the Big Bang), and it will be used to search for galaxies that existed at that time. The HUDF image was taken in a section of the sky with a low density of bright stars in the near-field, allowing much better viewing of dimmer, more distant objects. The image contains an estimated 10,000 galaxies. In August and September 2009, the Hubble’s Deep Field was expanded using the infrared channel of the recently attached Wide Field Camera 3 (WFC3). When combined with existing HUDF data, astronomers were able to identify a new list of potentially very distant galaxies.[2]

Located southwest of Orion in the southern-hemisphere constellation Fornax, the image covers 11.0 square arcminutes. This is just one-seventieth the solid angle subtended by the full moon as viewed from Earth, smaller than a 1 mm-by-1 mm square of paper held 1 meter away, and equal to roughly one thirteen-millionth of the total area of the sky. The image is oriented so that the upper left corner points toward north (−46.4°) on the celestial sphere.

This would look good on your wall.

Good show, I say!

Today’s Daily Mail (U.K.) writes of Damian Peach, Astronomer Photographer of the Year (2010)…

From detailed solar flares to an amazing image of Jupiter and two of its moons, this tour of our solar system has been captured by an amateur British astronomer in his back garden.

Damian Peach, an electronic engineer from Selsey, West Sussex, has spent the last ten years documenting the changing face of our solar system.

Spending a relatively modest £10,000 on a high-speed telescope and electrical equipment, Mr Peach’s crystal clear images are good enough to rival those of Nasa and the European Southern Observatory in Chile.

So much so that in 2010, he became the only Briton to win the prestigious Astronomy Photographer Of The Year Award for his composite photograph of Jupiter’s moons, Ganymede and Io, orbiting the stormy surface of the gas giant.

Mr Peach said: ‘It’s just fantastic that it’s possible to do something like this from your own back garden.

‘This has been made possible by recent leaps in technology. These days surprisingly good results are possible with small telescopes and low cost webcams.

‘The results possible for home astronomers now were not achievable until the 1990s by even the largest telescopes on Earth.

‘The resolution possible with large amateur telescopes could now be considered of a professional quality in what the images reveal on the planets.’

Great job, mate!

You can skip this step and go directly to the million-dollar images the space agencies put out, and get a monster-size print for a few bucks.

In Upstate New York on Saturday (Columbia County), the clouds went away to show a beautiful view of the stars. Light pollution was at a minimum and one of my friends, who spent some time skiing in New Zealand, commented on how the view from the Southern Hemisphere is completely different.

How appropriate that the Astronomy Picture of the Day (APOD) on 24 September 2011 was from Mangaia, one of the Cook Islands…

Explanation: From Sagittarius to Carina, the Milky Way Galaxy shines in this dark night sky above planet Earth’s lush island paradise of Mangaia. Familiar to denizens of the southern hemisphere, the gorgeous skyscape includes the bulging galactic center at the upper left and bright stars Alpha and Beta Centauri just right of center. About 10 kilometers wide, volcanic Mangaia the southernmost of the Cook Islands. Geologists estimate that at 18 million years old it is the oldest island in the Pacific Ocean. Of course, the Milky Way is somewhat older, with the galaxy’s oldest stars estimated to be over 13 billion years old. (Editor’s note: This image holds the distinction of being selected as winner in the Royal Observatory, Greenwich, Astronomy Photographer of the Year competition in the Earth and Space category.)

I simply must visit New Zealand some day, but I’ll settle for watching USA vs. Italy today in the Rugby World Cup — in New Zealand.