What's up in space

Solar Activity

Solar wind
speed: 458.0 km/sec   
density: 4.3 protons/cm3
explanation | more data    
Updated: Today at 1717 UT

X-ray Solar Flares
6-hr max: C1 1101 UT Mar15
24-hr: M1 0703 UT Mar15
explanation | more data     
Updated: Today at: 1700 UT

Sunspot AR1692 was involved in an M1-class sola flare on March 15th. Solar activity is picking up.   Credit: SDO/HMI

Solar wind flowing from this coronal hole could reach Earth on March 19-20.
Credit: SDO/AIA.

CME IMPACT: As expected, a coronal mass ejection (CME) hit Earth's magnetic field on March 15th at approximately 0500 UT. The impact was weak, but conditions for geomagnetic storming could develop as Earth passes through the CME's wake. High latitude sky watchers should be alert for auroras on March 15th and 16th.

POSSIBLE EARTH-DIRECTED CME: A magnetic filament snaking around sunspot AR1692 erupted on March 15th at about 0600 UT. The slow explosion, which took hours to unfold, produced an M1-class solar flare and a bright CME. SOHO (the Solar and Heliospheric Observatory) captured the CME just as it was leaving the sun: [click on: http://spaceweather.com/images2013/15mar13/m1cme_anim.gif for animation].

The central location of the explosion combined with multiple views of the CME from SOHO and NASA's twin STEREO spacecraft suggest that the cloud is heading almost directly toward Earth. If so, an impact would likely occur in 2 to 3 days, setting the stage for weekend auroras. Stay tuned for refined estimates of the arrival time.

THE MAGNITUDE OF COMET PAN-STARRS: "There seem to be a lot of pictures, but a shortage of magnitude estimates for Comet Pan-STARRS," says Richard Keen, professor of atmospheric sciences at the University of Colorado. "I saw it for the first time this evening, and got a magnitude estimate before the comet slipped behind a narrow cloud bank." Keen is an expert observer of astronomical brightness, especially that of lunar eclipses which he uses to study aerosols in the stratosphere. "The comet is magnitude +0.2 with a short, but bright vertical tail. It was quite visible to the unaided eye. After the [head of the comet] set behind the mountains, the tail was visible for two or three more minutes." A growing number of observers say they can see the comet with their unaided eye. Here it is on March 14th at sunset over Valley Forge, PA:

Visibility should continue to improve in the nights ahead as Pan-STARRS moves away from the sun. Keen's magnitude estimate of +0.2 means that the comet is approximately twice as bright as a first magnitude star. When it is framed by darker skies, it will really stand out. Tonight when the sun goes down, step outside, face west, and take a look: sky map.
More: NASA video, 3D orbit, ephemeris, light curves.    
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