Solar Hiccup

Image courtesy SDO/NASA

A solar flare explodes on May 9 in an image captured by NASA’s Solar Dynamics Observatory.

The phenomenon was short-lived and didn’t spark any coronal mass ejections, huge clouds of charged solar particles that erupt from the sun’s upper atmosphere.

The flare is shown in the 131 Angstrom wavelength of light—typically colored teal—which gave scientists the most detailed picture of the flare.

(See “New ‘Sunquake’ Trigger Found: Huge Solar Belches.”)

Stars Are Born

 

Image courtesy ESA/PACS/SPIRE, CEA/CNRS/INSU

The Cygnus-X stellar nursery stars in a “stunning” infrared picture released May 10 by the European Space Agency’s Herschel space observatory.

The chaotic jumble of dust and gas is an extremely active region of giant-star birth in the Cygnus constellation, some 4,500 light-years from Earth. (See another infrared picture of the Cygnus constellation.)

Sun Is Moving Slower Than Thought

“Shocking” find may redraw picture of solar system’s cosmic shield.

The young star LL Ori forms a bow shock as it moves through the Orion Nebula.

Image courtesy STScI/AURA/NASA

Andrew Fazekas

for National Geographic News

Published May 10, 2012

The sun is moving through the Milky Way slower than previously thought, according to new data from a NASA spacecraft.

From its orbit around Earth, the Interstellar Boundary Explorer (IBEX) satellite measured the speeds of interstellar particles entering at the fringes of our solar system, 9 billion miles (14.5 billion kilometers) from the sun.

(Related: “‘Alien’ Particles Found Invading Our Solar System—A First.”)

Plugging the new data into computer models, the IBEX team calculates that the sun is moving at about 52,000 miles (83,700 kilometers) an hour—about 7,000 miles (11,000 kilometers) slower than thought.

The discovery suggests that the protective boundary separating our solar system from the rest of the galaxy is missing a bow shock, a major structural component thought to control the influx of high-energy cosmic rays.

(See “New Hubble Videos Show Star Jets in Action.”)

The sun is constantly sending out charged particles in all directions, forming a cocoon around the solar system called the heliosphere.

Like a boat moving through water, it’s long been thought that the “bow” of the heliosphere forms a crescent-shaped shockwave as our solar system plows through the surrounding cloud of interstellar gas. (See “Solar System’s ‘Nose’ Found; Aimed at Constellation Scorpius.”)

But the new IBEX findings mean the sun is moving so slow that pressure from material flowing around the heliosphere is 25 percent lower than expected—not enough for a bow shock.

Until now, “all the solar system models and theories included a bow shock,” said study leader David McComas of the Southwest Research Institute in San Antonio, Texas.

“Having learned for nearly three decades about it, I was literally shocked when we found it was missing.”

Cosmic-Ray Shielding Key for Life?

The absence of a bow shock is significant, McComas said, because it may indicate that the heliosphere is actually more robust than thought.

With less pressure from outside material, the boundary region isn’t being compressed and therefore weakened as much as expected, which means it should better repel cosmic rays.

(Related: “Solar System ‘Force Field’ Shrinks Fast.”)

And understanding exactly how the heliosphere acts as a gatekeeper for cosmic rays could help scientists evaluate the chances for life on other worlds.

According to McComas, some researchers believe that the cosmic rays that do get through the heliosphere can impact Earth’s climate, because the high-energy particles can ionize—or electrically charge—matter in the atmosphere, leading to heightened cloud formation and lightning generation.

Other experts think the particles could even be related to bursts of evolution or extinction in our planet’s history, because the radiation can influence DNA patterns.

(Also see “Ancient Mass Extinctions Caused by Cosmic Radiation, Scientists Say.”)

For now, the science behind how cosmic rays have influenced Earth is quite controversial, said Seth Redfield, an astronomer from Wesleyan University in Connecticut who was not involved with the new IBEX study.

Still, considering the rays’ expected effects, Redfield said, “it seems obvious to me that there will be scenarios or times when the cosmic-ray flux on a planet is important and [is] having a major influence on the evolution of the planetary atmosphere or even on biological processes on its surface.”

In that case, astronomers assessing the habitability of alien planets may need to start considering not only the chances for liquid water but also the strength of other stars’ protective cocoons, study leader McComas said.

“There is no doubt,” he said, “that questions about cosmic-ray shielding go right to the heart of some really important questions related to life as we know it.”

The slower-sun study appears in this week’s issue of the journal Science.

New Planet Found in Our Solar System?

Odd orbits of remote objects hint at unseen world, new calculations suggest.

Richard A. Lovett in Timberline Lodge, Oregon
for
National Geographic News
Published May 11, 2012

An as yet undiscovered planet might be orbiting at the dark fringes of the solar system, according to new research.

Too far out to be easily spotted by telescopes, the potential unseen planet appears to be making its presence felt by disturbing the orbits of so-called Kuiper belt objects, said Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro.

Kuiper belt objects are small icy bodies—including some dwarf planets—that lie beyond the orbit of Neptune.

Once considered the ninth planet in our system, the dwarf planet Pluto, for example, is one of the largest Kuiper belt objects, at about 1,400 miles (2,300 kilometers) wide. Dozens of the other objects are hundreds of miles across, and more are being discovered every year.

(See “Three New ‘Plutos’? Possible Dwarf Planets Found.”)

What’s intriguing, Gomes said, is that, according to his new calculations, about a half dozen Kuiper belt objects—including the remote body known as Sedna—are in strange orbits compared to where they should be, based on existing solar system models. (Related: “Pluto Neighbor Gets Downsized.”)

The objects’ unexpected orbits have a few possible explanations, said Gomes, who presented his findings Tuesday at a meeting of the American Astronomical Society in Timberline Lodge, Oregon.

“But I think the easiest one is a planetary-mass solar companion”—a planet that orbits very far out from the sun but that’s massive enough to be having gravitational effects on Kuiper belt objects.

Mystery Planet a Captured Rogue?

For the new work, Gomes analyzed the orbits of 92 Kuiper belt objects, then compared his results to computer models of how the bodies should be distributed, with and without an additional planet.

If there’s no distant world, Gomes concludes, the models don’t produce the highly elongated orbits we see for six of the objects.

How big exactly the planetary body might be isn’t clear, but there are a lot of possibilities, Gomes added.

Based on his calculations, Gomes thinks a Neptune-size world, about four times bigger than Earth, orbiting 140 billion miles (225 billion kilometers) away from the sun—about 1,500 times farther than Earth—would do the trick.

But so would a Mars-size object—roughly half Earth’s size—in a highly elongated orbit that would occasionally bring the body sweeping to within 5 billion miles (8 billion kilometers) of the sun.

Gomes speculates that the mystery object could be a rogue planet that was kicked out of its own star system and later captured by the sun’s gravity. (See “‘Nomad’ Planets More Common Than Thought, May Orbit Black Holes.”)

Or the putative planet could have formed closer to our sun, only to be cast outward by gravitational encounters with other planets.

However, actually finding such a world would be a challenge.

To begin with, the planet might be pretty dim. Also, Gomes’s simulations don’t give astronomers any clue as to where to point their telescopes—”it can be anywhere,” he said.

No Smoking Gun

Other astronomers are intrigued but say they’ll want a lot more proof before they’re willing to agree that the solar system—again—has nine planets. (Also see “Record Nine-Planet Star System Discovered?”)

“Obviously, finding another planet in the solar system is a big deal,” said Rory Barnes, an astronomer at the University of Washington. But, he added, “I don’t think he really has any evidence that suggests it is out there.”

Instead, he added, Gomes “has laid out a way to determine how such a planet could sculpt parts of our solar system. So while, yes, the evidence doesn’t exist yet, I thought the bigger point was that he showed us that there are ways to find that evidence.”

Douglas Hamilton, an astronomer from the University of Maryland, agrees that the new findings are far from definitive.

“What he showed in his probability arguments is that it’s slightly more likely. He doesn’t have a smoking gun yet.”

And Hal Levison, an astronomer at the Southwest Research Institute in Boulder, Colorado, says he isn’t sure what to make of Gomes’s finding.

“It seems surprising to me that a [solar] companion as small as Neptune could have the effect he sees,” Levison said.

But “I know Rodney, and I’m sure he did the calculations right.”

About Chandra

Since its launch on July 23, 1999, the Chandra X-ray

Observatory has been NASA’s flagship mission for X-ray astronomy, taking its place in the fleet of “Great Observatories.”

Who we are
NASA’s Chandra X-ray Observatory is a telescope specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Because X-rays are absorbed by Earth’s atmosphere, Chandra must orbit above it, up to an altitude of 139,000 km (86,500 mi) in space. The Smithsonian’s Astrophysical Observatory in Cambridge, MA, hosts the Chandra X-ray Center which operates the satellite, processes the data, and distributes it to scientists around the world for analysis. The Center maintains an extensive public web site about the science results and an education program.
What we do
Chandra carries four very sensitive mirrors nested inside each other. The energetic X-rays strike the insides of the hollow shells and are focussed onto electronic detectors at the end of the 9.2- m (30-ft.) optical bench. Depending on which detector is used, very detailed images or spectra of the cosmic source can be made and analyzed.
What we are excited about

Chandra has imaged the spectacular, glowing remains of exploded stars, and taken spectra showing the dispersal of elements. Chandra has observed the region around the supermassive black hole in the center of our Milky Way, and found black holes across the Universe. Chandra has traced the separation of dark matter from normal matter in the collision of galaxies in a cluster and is contributing to both dark matter and dark energy studies. As its mission continues, Chandra will continue to discover startling new science about our high-energy Universe.

A Tour of SN 1979C (High Definition)

 

  • SN 1979C, a supernova in the galaxy M100, may be the youngest black hole in the so-called local Universe.
  • Astronomers have seen many gamma-ray bursts, which are likely the births of young black holes, but these are much more distant.
  • If SN 1979C does indeed contain a black hole, it will give astronomers a chance to learn more about which stars make black holes and which create neutron stars.
  • SN 1979C was first reported by an amateur astronomer, and some 25 years later space-based telescopes picked up the case.

This composite image shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. In this image, Chandra’s X-rays are colored gold, while optical data from ESO’s Very Large Telescope are shown in yellow-white and blue, and infrared data from Spitzer are red. The location of the supernova, known as SN 1979C, is labeled (roll your mouse over the image above to view the labeled image).

SN 1979C was first reported to be seen by an amateur astronomer in 1979. The galaxy M100 is located in the Virgo Cluster about 50 million light years from Earth. This approximately 30-year age, plus its relatively close distance, makes SN 1979C the nearest example where the birth of a black hole has been observed, if the interpretation by the scientists is correct.

Data from Chandra, as well as NASA’s Swift, the European Space Agency’s XMM-Newton and the German ROSAT observatory revealed a bright source of X-rays that has remained steady for the 12 years from 1995 to 2007 over which it has been observed. This behavior and the X-ray spectrum, or distribution of X-rays with energy, support the idea that the object in SN 1979C is a black hole being fed either by material falling back into the black hole after the supernova, or from a binary companion.

The scientists think that SN 1979C formed when a star about 20 times more massive than the Sun collapsed. It was a particular type of supernova where the exploded star had ejected some, but not all of its outer, hydrogen-rich envelope before the explosion, so it is unlikely to have been associated with a gamma-ray burst (GRB). Supernovas have sometimes been associated with GRBs, but only where the exploded star had completely lost its hydrogen envelope. Since most black holes should form when the core of a star collapses and a gamma-ray burst is not produced, this may be the first time that the common way of making a black hole has been observed.

The very young age of about 30 years for the black hole is the observed value, that is the age of the remnant as it appears in the image. Astronomers quote ages in this way because of the observational nature of their field, where their knowledge of the Universe is based almost entirely on the electromagnetic radiation received by telescopes.

Fast Facts for SN 1979C:
Credit X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech
Scale Image is 5 by 4 arcmin, (72,000 x 58,000 light years)
Category Supernovas & Supernova Remnants , Black Holes
Coordinates (J2000) RA 12h 22m 54.9s | Dec +15° 49′ 21”
Constellation Coma Berenices
Observation Date Feb 18, 2006 & Apr 20, 2008
Observation Time 15 hours 16 min
Obs. ID 6727, 9121
Color Code X-ray (Gold); Optical (Yellow-white, Blue), Infrared (Red)
Instrument ACIS
References Patnaude, D, et al. 2010, New Astronomy (in press); arXiv:0912.1571
Distance Estimate About 50 million light years
Release Date November 15, 2010

Arp 147 in 60 Seconds (High Definition)

  • Arp 147 contains a spiral galaxy (right) that collided with an elliptical galaxy (left), triggering a wave of star formation.
  • Many of these newly-born massive stars raced through their lives and ended with supernova explosions, some as black holes.
  • A ring of these black holes can be seen in the Chandra data (pink) around the spiral galaxy.

Just in time for Valentine’s Day comes a new image of a ring — not of jewels — but of black holes. This composite image of Arp 147, a pair of interacting galaxies located about 430 million light years from Earth, shows X-rays from the NASA’s Chandra X-ray Observatory (pink) and optical data from the Hubble Space Telescope (red, green, blue) produced by the Space Telescope Science Institute (STScI) in Baltimore, Md.

Arp 147 contains the remnant of a spiral galaxy (right) that collided with the elliptical galaxy on the left. This collision has produced an expanding wave of star formation that shows up as a blue ring containing in abundance of massive young stars. These stars race through their evolution in a few million years or less and explode as supernovas, leaving behind neutron stars and black holes.

A fraction of the neutron stars and black holes will have companion stars, and may become bright X-ray sources as they pull in matter from their companions. The nine X-ray sources scattered around the ring in Arp 147 are so bright that they must be black holes, with masses that are likely ten to twenty times that of the Sun.

An X-ray source is also detected in the nucleus of the red galaxy on the left and may be powered by a poorly-fed supermassive black hole. This source is not obvious in the composite image but can easily be seen in the X-ray image. Other objects unrelated to Arp 147 are also visible: a foreground star in the lower left of the image and a background quasar as the pink source above and to the left of the red galaxy.

Infrared observations with NASA’s Spitzer Space Telescope and ultraviolet observations with NASA’s Galaxy Evolution Explorer (GALEX) have allowed estimates of the rate of star formation in the ring. These estimates, combined with the use of models for the evolution of binary stars have allowed the authors to conclude that the most intense star formation may have ended some 15 million years ago, in Earth’s time frame.

These results were published in the October 1st, 2010 issue of The Astrophysical Journal. The authors were Saul Rappaport and Alan Levine from the Massachusetts Institute of Technology, David Pooley from Eureka Scientific and Benjamin Steinhorn, also from MIT.

Fast Facts for Arp 147:
Credit X-ray: NASA/CXC/MIT/S.Rappaport et al, Optical: NASA/STScI
Scale Image is 54 arcsec across. (about 115,000 light years across)
Category Normal Galaxies & Starburst Galaxies
Coordinates (J2000) RA 03h 11m 18.9s | Dec +01° 18′ 52.99”
Constellation Cetus
Observation Date 9/13/2009, 9/15/2009
Observation Time 11 hours 49 min
Obs. ID 11280, 11887
Color Code Optical (Red, Green, Blue); X-ray (Magenta)
Instrument ACIS
Also Known As Ring Galaxy
Distance Estimate 440 million light years
Release Date February 9, 2011