02/06/2013Picture of the DaySaturn’s moon Hyperion
Hyperion is, at 410 x 260 x 220 kilometers (255 x 163 x 137 miles) in diameter, the largest of Saturn’s irregularly-shaped moons and the largest irregularly-shaped moon in the Solar System. A possible explanation for the irregular shape is that Hyperion is a fragment of a larger body that was broken by a large impact in the distant past.
The moon has a notably reddish tint when viewed in natural color. The red color was toned down in this false-color view, and the other hues were enhanced, in order to make more subtle color variations across Hyperion’s surface more apparent.
Hyperion’s surface shows an enormous ridge and is covered with deep, sharp-edged craters that give it the appearance of a giant sponge. Dark material fills the bottom of each crater. The reddish substance contains long chains of carbon and hydrogen. The largest crater on Hyperion is approximately 121.57 km in diameter and 10.2 km deep.
This cold moon, with a temperature of 93 K (−180 C), consists for about 40 percent of empty space . This porosity allows craters to remain nearly unchanged over the eons. Hyperion’s low density indicates that it is composed largely of water ice with only a small amount of rock.
Hyperion orbits Saturn in 21.28 days in a fairly eccentric orbit and it’s rotation is chaotic, that is, its axis of rotation wobbles so much that its orientation in space is unpredictable. Hyperion is the only moon in the Solar System known to rotate chaotically. It is also the only regular natural satellite in the Solar System not to be tidally locked.
LINK: [link to annesastronomynews.com
] “Ribbon” Of Energy at the Edge of our Solar System Explained
In a paper published Feb. 4, 2013, in the Astrophysical Journal, researchers, including lead author Nathan Schwadron of the University of New Hampshire, propose a “retention theory” that for the first time explains all the key observations of this astrophysical enigma.
“If the theory is correct,” Schwadron notes, “the ribbon can be used to tell us how we’re moving through the magnetic fields of the interstellar medium and how those magnetic fields then influence our space environment.”
In particular, these strong magnetic fields appear to play a critical role in shaping our heliosphere—the huge bubble that surrounds our Solar System and shields us from much of harmful galactic cosmic radiation that fills our galaxy. This may have important ramifications for the history and future of radiation in space, and its impact here on Earth, as the heliosphere changes in response to changing conditions in the interstellar medium or the “space between the stars.”
According to the retention theory, the ribbon exists in a special location where neutral hydrogen atoms from the solar wind move across the local galactic magnetic field. Neutral atoms are not affected by magnetic fields, but when their electrons get stripped away they become charged ions and begin to gyrate rapidly around magnetic field lines. That rapid rotation creates waves or vibrations in the magnetic field, and the charged ions then become trapped by the waves. This is the process that creates the ribbon.
Nathan Schwadron, an associate professor at UNH’s Institute for the Study of Earth, Oceans, and Space and department of physics, says: “Think of the ribbon as a harbor and the solar wind particles it contains as boats. The boats can be trapped in the harbor if the ocean waves outside it are powerful enough. This is the nature of the new ribbon model. The ribbon is a region where particles, originally from the solar wind, become trapped or ‘retained’ due to intense waves and vibrations in the magnetic field.”
READ MORE AT: [link to annesastronomynews.com
] Earth-like Planets Are Right Next Door
“We thought we would have to search vast distances to find an Earth-like planet. Now we realize another Earth is probably in our own backyard, waiting to be spotted,” said Harvard astronomer and lead author Courtney Dressing (CfA).
Dressing presented her findings today in a press conference at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
Red dwarf stars are smaller, cooler, and fainter than our Sun. An average red dwarf is only one-third as large and one-thousandth as bright as the Sun. From Earth, no red dwarf is visible to the naked eye.
Despite their dimness, these stars are good places to look for Earth-like planets. Red dwarfs make up three out of every four stars in our galaxy for a total of at least 75 billion. The signal of a transiting planet is larger since the star itself is smaller, so an Earth-sized world blocks more of the star’s disk. And since a planet has to orbit a cool star closer in order to be in the habitable zone, it’s more likely to transit from our point of view.
Dressing culled the Kepler catalog of 158,000 target stars to identify all the red dwarfs. She then reanalyzed those stars to calculate more accurate sizes and temperatures. She found that almost all of those stars were smaller and cooler than previously thought.
MORE AT: [link to annesastronomynews.com
] A Massive Stellar Burst, Before the Supernova
Digging through the Palomar Transient Factory (PTF) data archive housed at the Department of Energy's National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory (Berkeley Lab), astronomers have found the first causal evidence that these massive stars shed huge amounts of material in a "penultimate outburst" before final detonation as supernovae.
A focused search for Type IIn SN precursor bursts, conducted by Eran Ofek of Israel's Weizmann Institute and the PTF team, led to this finding. Their results were published in the February 7, 2013 issue of Nature. PTF is an international collaboration that brings together researchers, universities, observatories and Berkeley Lab to hunt for supernovae and other astronomical objects.
The Causal Link
Massive stars -- somewhere between eight and 100 times the mass of our Sun -- spend much of their lives fusing hydrogen (the lightest element) into increasingly heavier elements, like helium, oxygen, carbon and so on. In the end, there is almost nothing left but an iron core. Eventually, that core collapses, releasing a tremendous amount of energy as neutrinos, magnetic fields and shock waves and destroying the star in the process. From Earth, this explosive event is observed as a supernova. If astronomers detect hydrogen, the event is classified as a Type II supernova. And if the hydrogen-emission line is narrow, the event is classified as a Type IIn (for "narrow").
In the case of Type IIn events, scientists suspected that the narrow emission line occurs as light from the event passes through a thin sphere of hydrogen that was already surrounding the star before it went supernova. Some believed that the dying star might have shed this shell of material before it self-destructed, but until recently there was no evidence to link such an outburst to an actual supernova.
LINK: [link to www.sciencedaily.com
] Mapping Mars
Nearly 90% of Mars' surface has been mapped by the high-resolution stereo camera on ESA's Mars Express, which celebrates ten years since launch this June.
The mosaic comprises 2702 individual swaths of the martian surface, up to and including the spacecraft's 10 821st orbit of the planet, which it completed on 30 June 2012.
In total, 87.8% of the surface has been mapped at any resolution, with 61.5% mapped at a resolution of 20 m per pixel or better. The map is equatorially aligned, meaning that regions at the poles appear distorted.
The map provides a record of all locations observed by the camera simultaneously in red, green, blue and nadir channels.
Images that were particularly affected by dust or atmospheric effects have not been included in the mosaic. These effects are more prevalent in the region shown in the top right of the map, as reflected by the greater number of 'missing' pieces there.
The subtle variation in colour tones are due partly to changes in dust content in the atmosphere, but mostly due to the change in solar elevation as the spacecraft moves around the planet, experiencing different illumination conditions.
Upon closer inspection, many well-known geological features are revealed. Towards the top left stands Olympus Mons, the tallest volcano in the Solar System at over 21 km high. A chain of three volcanoes making up the Tharsis Montes lies just below and to the right.
Moving further right again uncovers the Solar System's largest canyon, Valles Marineris. This giant cavern plunges 10 km deep and runs over 4000 km.
LINK: [link to www.marsdaily.com
] Sun News 02/06/2013
Product: Forecast Discussion
:Issued: 2013 Feb 06 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction CenterSolar Activity
.24 hr Summary...
Solar activity was low. Region 1667 (N22E08, Dso/beta) produced a C8/1f
flare at 06/0021 UTC associated with a filament eruption, a Type II
radio sweep (estimated shock speed 548 km/s), a Type IV radio sweep and
a coronal mass ejection (CME). Sparse coronagraph imagery indicated the
CME may have an Earthward component with a trajectory somewhat north of
the ecliptic plane. Further analysis is required to determine whether
the CME is likely to be geoeffective. Despite its flare activity, Region
1667 showed no significant changes and maintained a simple beta magnetic
configuration. Region 1669 (N08E44, Bxo/beta) showed gradual spot decay
during the period and produced a C1/Sf flare at 06/0558 UTC..Forecast...
Solar activity is likely to be low during the period (06 - 08 Feb) with
a slight chance for an M-class flare.Energetic Particle
.24 hr Summary...
The greater than 10 MeV proton flux at geosynchronous orbit was at
background levels. The greater than 2 MeV electron flux at
geosynchronous orbit was at normal to moderate levels with a slight
The greater than 10 MeV proton flux at geosynchronous orbit is expected
to remain at background levels through the period (06 - 08 Feb). The
greater than 2 MeV electron flux at geosynchronous orbit is expected to
be at normal levels during most of the period.Solar Wind
.24 hr Summary...
Wind speeds remained low and gradually decreased from 372 to 297 km/s
during the period. A solar sector boundary crossing (toward (-) to away
(+)) occurred around 05/1630 UTC. IMF Bt varied from 2 to 6 nT. IMF Bz
ranged from +/- 4 nT and was northward during most of the period.Forecast...
No significant solar wind changes are expected during the period (06 -
.24 hr Summary...
The geomagnetic field was quiet..Forecast...
The geomagnetic field is expected to remain at quiet levels during the
period (06 - 08 Feb).
LINK: [link to www.solarham.net
Streamer: [link to iswa.gsfc.nasa.gov
[link to iswa.gsfc.nasa.gov
[link to www.gdgps.net
Active Region Map: [link to sidc.oma.be
STAR Active region map: [link to solen.info
EVE 3-Day: [link to lasp.colorado.edu
Magnetometer: [link to www.swpc.noaa.gov
Ionospheric Electrons: [link to www.ips.gov.au
Ionospheric foF2: [link to www.ips.gov.au
Surface Heat Index (USA): [link to weather.unisys.com
Sea Surface Temps (2/5/13): [link to www.ssec.wisc.edu
] Estimated Planetary K-Index:
[link to www.solarham.net
] 3MIN News February 6, 2013: 8.0 Santa Cruz, Electroquake Recap, Solar Eruption