In the Sky!
Look here for news about featured objects currently in the sky or objects that will soon be in the sky.
Comet C/2011 L4 PANSTARRS
What is history of this comet?
Comet C/2011 L4 (PANSTARRS), is a non-periodic comet discovered in June 2011. The comet was discovered using the Pan-STARRS telescope located near the summit of Haleakala, on the island of Maui in Hawaii.
Will the comet hit the Earth or Sun?
No the comet will never get closer than 100 million miles to the Earth or 30 million miles from the Sun.
When can I see the comet?
Based on the trend to date, both the IAU’s Minor Planet Center and JPL’s Horizons system predict that perihelion will occur March 10th or 11th. By then the comet will be inside Mercury’s orbit and close to magnitude 0 in brightness. It will become visible immediately after sunset, on our western horizon by March 13th. If possible get away from city or urban lights to view the comet
On March 13th, the crescent Moon will be just above the comet. Its maximum magnitude, although uncertain, is likely to be at least +2, and possibly brighter, with a 10° tail. This tail will point up and away from the Sun. Over the next few weeks it will move from the western horizon to the northwestern horizon after sunset and higher in the sky, but fading. Binoculars maybe needed.
How bright will the comet get?
The comet will pass closest to Earth on 5 March 2013 at a distance of 100 million miles. Its closest approach to the Sun will be on 10 March 2013. However, during this time it will be too close to the Sun to be visible from St. Louis. An estimate from January 2013 predicts the comet may brighten to apparent magnitude +2 (roughly equivalent to the North Star). Earlier estimates had predicted a greater showing of roughly magnitude 0.
Why are brightness estimates so difficult?
Estimating the brightness it like predicting the weather, the further out the forecast the more uncertainty. Comet brightness depends on many factors, distance to the Sun,?????????? distance to the Earth. However, there are other important factors, such as the amount of volatile gas and dust the comet nucleus contains. If the Sun?s rays ?evaporate? this gas and dust from the comet nucleus, it can form a bright atmosphere called a coma and tail. The larger the coma and tail, the more sunlight is reflected off the comet and it appears brighter. Since Comet C/2011 L4 has not been seen before, we don?t know for sure if it a comet rich in gas and dust. Professional and amateur astronomers are tracking the comet and monitoring the size of the coma and tail. Brightness predictions will be updated, as the comet gets closer to the sun.
What are the key dates?
- March 5–12: Comet nearest to Earth and Sun but not visible from St. Louis skies.
- March 13: Comet on western horizon after sunset, look directly below the thin crescent Moon. The comet?s tail will point up in the direction of the Moon.
- March 14–29: The comet gets higher in the sky each evening after sunset, however it will also decrease in brightness as it heads away from the Sun
- March 30-April 5: The comet moves northward each evening and appears below the constellation Cassiopeia, which is shaped like a ?W? above the northwest horizon.
- April 5–10: The comet appears to the right of the Andromeda Galaxy. Use binoculars to see this object.
How do I find up-to-date information?
Many websites and news services will publish articles as the comet. Reliable websites are as follows:
- NASA?s Jet Propulsion Laboratory - http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011L4
- International Astronomical Union (IAU) ? Minor Planets Section - http://mpcapp1.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=CK11L040
- Sky and Telescope - http://media.skyandtelescope.com/documents/PanST ARRS.pdf
- The Universe Today - http://www.universetoday.com/97208/comet-pan-starrs-how-bright-will-it-get/
- Heavens Above - http://www.heavens- above.com/comet.aspx?cid=C%2F2011%20L4&lat=0&lng=0&loc=unspecified&alt= 0&tz=cet
Is there another bright comet visible in 2013? Yes, comet ISON C/2012 S1 will be visible from St Louis before sunrise in November and December. This comet has the potential to be brighter than PANSTARRS. We will publish information on this comet later in 2013.