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speculated before about the possible existence of different types of neutron stars, but there has never been any clear observational evidence that there is really more than one type

astronomers analysed data on a large sample of high-mass X-ray binaries

double star systems in which a fast-spinning neutron star orbits a massive young companion

neutron star in these systems also periodically siphons off material from its partner

neutron star becomes an X-ray pulsar

because by timing their pulses, astronomers can accurately measure the neutron star spin periods

detected two distinct groupings in a large set of spin periods measured in this way

one group of neutron stars typically spinning once every 10 seconds

the other once every 5 minutes

led them to conclude that the two distinct neutron star populations formed via two different supernova channels

results help solve a mystery of why some coronal mass ejections produce almost no energetic protons that reach the Earth, while others produce huge amounts

inferred the continuous production of protons in the 30-to-100-MeV (million electron volt) range due to the flare

MESSENGER’s Neutron Spectrometer was able to record neutrons from this flare over a period of six to ten hours

at least some moderate-sized flares continuously produce high-energy neutrons in the solar corona

Solar flares spew high-energy neutrons into interplanetary space. Typically, these bursts last about 50 to 60 seconds at the sun.

forms an extended seed population in interplanetary space that can be further accelerated by the massive shock waves produced by the flares

another population results from the decay of the neutrons near the sun

About 90 percent of all ions produced by a solar flare remain locked to the sun on closed magnetic lines

It appears that these seed populations of energetic protons near the sun could provide the answer

Sometimes they’re in the right place for the shock waves to send them toward Earth

seed populations are not evenly distributed

at other times they’re in locations where the protons are accelerated in directions that don’t take them near Earth

Energetic protons from solar flares can damage Earth-orbiting satellites and endanger astronauts on the International Space Station or on missions to the Moon and Mars.

scientists need to know a lot more about the mechanisms that produce flares and which flare events are likely to be dangerous

At some point they hope to be able to predict space weather — where precipitation is in the form of radiation — with the same accuracy that forecasters predict rain or snow on Earth.

The beauty of MESSENGER is that it’s going to be active from the minimum to the maximum solar activity during Solar Cycle 24

observe the rise of a solar cycle much closer to the sun than ever before

will function much like a high-powered magnifying glass

instrument will take color pictures of features as tiny as 12.5 microns — smaller than the width of a human hair

MAHLI sits on the end of Curiosity's five-jointed, 7-foot (2.1-meter) robotic arm

Mars Descent Imager (MARDI)

small camera located on Curiosity's main body, will record video of the rover's descent to the Martian surface

will click on a mile or two above the ground, as soon as Curiosity jettisons its heat shield. The instrument will then take video at five frames per second until the rover touches down. The footage will help the MSL team plan Curiosity's Red Planet rovings, and it should also provide information about the geological context of the landing site, the 100-mile-wide

Sample Analysis at Mars (SAM)

makes up about half of the rover's science payload.

a suite of three separate instruments — a mass spectrometer, a gas chromatograph and a laser spectrometer

will search for carbon-containing compounds, the building blocks of life as we know it

look for other elements associated with life on Earth, such as hydrogen, oxygen and nitrogen

The rover's robotic arm will drop samples into SAM via an inlet on the rover's exterior

Chemistry and Mineralogy (CheMin)

CheMin will identify different types of minerals on Mars and quantify their abundance

will help scientists better understand past environmental conditions on the Red Planet

CheMin has an inlet on Curiosity's exterior to accept samples delivered by the rover's robotic arm

will shine a fine X-ray beam through the sample, identifying minerals' crystalline structures based on how the X-rays diffract

Chemistry and Camera (ChemCam)

This instrument will fire a laser at Martian rocks from up to 30 feet (9 meters) away and analyze the composition of the vaporized bits

help the mission team determine from afar whether or not they want to send the rover over to investigate a particular landform

The laser sits on Curiosity's mast, along with a camera and a small telescope

Three spectrographs sit in the rover's body, connected to the mast components by fiber optics

spectrographs will analyze the light emitted by excited electrons in the vaporized rock samples

Alpha Particle X-Ray Spectrometer (APXS)

sits at the end of Curiosity's arm, will measure the abundances of various chemical elements in Martian rocks and dirt

APXS will shoot out X-rays and helium nuclei. This barrage will knock electrons in the sample out of their orbits, causing a release of X-rays. Scientists will be able to identify elements based on the characteristic energies of these emitted X-rays

Dynamic Albedo of Neutrons (DAN)

located near the back of Curiosity's main body, will help the rover search for ice and water-logged minerals beneath the Martian surface

The instrument will fire beams of neutrons at the ground, then note the speed at which these particles travel when they bounce back. Hydrogen atoms tend to slow neutrons down, so an abundance of sluggish neutrons would signal underground water or ice

should be able to map out water concentrations as low as 0.1 percent at depths up to 6 feet (2 m).

Radiation Assessment Detector (RAD)

instrument will measure and identify high-energy radiation of all types on the Red Planet, from fast-moving protons to gamma rays

designed specifically to help prepare for future human exploration of Mars

will allow scientists to determine just how much radiation an astronaut would be exposed to on Mars

Rover Environmental Monitoring Station (REMS)

partway up Curiosity's mast, is a Martian weather station

measure atmospheric pressure, humidity, wind speed and direction, air temperature, ground temperature and ultraviolet radiation.

integrated into daily and seasonal reports

MSL Entry, Descent and Landing Instrumentation (MEDLI)

MEDLI isn't one of Curiosity's 10 instruments

will measure the temperatures and pressures the heat shield experiences as the MSL spacecraft streaks through the Martian sky

will tell engineers how well the heat shield, and their models of the spacecraft's trajectory, performed

data to improve designs for future Mars-bound spacecraft

In active mode, it is sensitive enough to detect water content as low as one-tenth of one percent in the ground beneath the rover.

With pulses lasting about one microsecond and repeated as frequently as 10 times per second

The generator will be able to emit a total of about 10 million pulses during the mission, with about 10 million neutrons at each pulse.

DAN can tell us how the shallow subsurface may differ from what the rover sees at the surface. None of our other instruments have the ability to do this

will provide the ability to detect hydrated minerals or water ice in the shallow subsurface

will also provide a ground-truth calibration for the measurements that the gamma-ray and neutron detectors on Odyssey have made and continue to make

enhancing the value of that global data set