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Object of the Week January 31, 2016 - NGC4314 "Benedicts Galaxy"
NGC 4314
UGC7443
Coma Berenices
RA 12 22 32.2
DEC 29 53 47
Type: Galaxy
Class: SN(rs)a
Mag: 11.4
Size: 4.3' x 3.6'
This weeks OOTW is a beautiful barred spiral 40million light years distant in the constellation Coma Berenices. In the eyepiece of a larger scope, NGC 4314, elongated ENE-WSW in orientation, is nicely framed by 3 13-14th (my estimate) magnitude stars forming right angle triangle. I have two observations of this object, my first coming January 7th, 2010 with Jimi's 48". (Both sets of notes below are verbatim from my handwritten notes)
488x A beautiful barred spiral! Rather bright orientated E-W. Arms rather weak but direct vision. Both arms visible curling back around.
I have another observation just a month later in my 25". Conditions were not nearly as good for the second as SQM readings for my first observation were on the order of 21.74 and for my second that dropped to nearly 21 flat.
242x, 315x Stellar core with bar. Outer arms visible with AV. Stellar core. Mottling throughout. Within a triangle of 3 13th or so mag stars.
What makes this object so interesting for this weeks OOTW isn't so much the view in the EP but the science behind its evolution. NGC 4314 is deemed a nuclear ring galaxy or a galaxy containing a defined star forming region in the shape of a ring.
In 1976 Fritz Benedict, a senior research scientist at the University of Texas, came upon this galaxy using the 2.7 meter at McDonald Observatory, just down the road from where I first observed NGC4314 with Jimis 48". A rather unassuming galaxy, he noticed what appeared to be a superimposed spiral galaxy atop of 4314. His studies revealed he was seeing a ring of relatively new stars. But how can this be? How can an old galaxy which contains no other known star forming regions contain a ring of relatively young stars? Fast forward to 1991.
Having been a member of the Hubble Space Telescope Astrometry Science Team since 1977, Fritz was granted use of the space telescope in 1991 and again in 1995. His research revealed some very interesting physics. Fritz and his team believe that NGC4314 must have collided with another galaxy at some point in its 10 billion year old life. During this collision, many of the necessary elements to fuel continuous star birth would have been stripped out of both galaxies, effectively slowing star formation to a crawl. So what gas and dust remained within the central portions of the galaxy could have been swept up by the inner arms and concentrated into this ring, igniting the birth of new stars. Measuring the age of these stars revealed them to be anywhere from one to fifteen millions years old, mere babies compared to the old age of NGC4314.
One interesting note about a possible 2nd ring. Just outside of this young ring may be an older ring. This ring contains stars on the order of 50-200 million years old, rather distinct from the very young stars in the first ring. As stars and gas orbit the center of the galaxy, gravitational interactions between these outer and the inner rings condense gas and dust lending to new star formation.
So the next time you observe this galaxy and notice what appears to be a bright stellar core, understand you're looking at a ring, approximately 1000 light years across, created by the formation of stars in a galaxy that is otherwise devoid of the necessary ingredients to form new stars.
Very interesting!
And without fail,
"Give it a go and let us know!"
Attachment 1986
The image on the right is the enlarged area
of the area inside the square on the left.
Credit: HST
