Physics Photo of the Week
November 16, 2012
Jupiter in Taurus
Look
up in the high eastern sky any night this November and you
see the Solar System's largest planet, Jupiter, dominating
the scene. This time-exposure with a tripod-mounted
digital camera (eight 10-second exposures aligned and added
together) makes many more stars visible than the un-aided
eye can see.
This part of the sky is in the constellation of Taurus,
the bull. The famous Pleiades star cluster (the "seven
sisters") is plainly visible in the top of the image
resembling a tiny "dipper". Less well-known is the
much larger Hyades cluster of stars dominating the lower
central part of the image. The Hyades cluster really
is about the same physical size as the Pleiades, it is much
closer to us (about 1/3 the distance as the Pleiades).
Where's the bull? The long exposure that captures
so many stars masks the 
familiar
shapes of the asterisms. The bright stars are subdued
and the faint stars are given so much visibility. The
apparent field is too crowded. The bull's nose is
actually a "V" formation that is quite visible with the
naked eye. The "V" is essentially an outline of the
brighter stars of the Hyades shown in the image at right.
The brightest star in Taurus, Aldebaran, is also
indicated. The photograph largely suppresses the
brightness of Aldebaran. It is very dominant in the
constellation, but not nearly as bright as Jupiter.
Click on the Jupiter-Aldebaran
image and see a much larger image that clearly shows
the importance of Aldebaran.
A close-up look at the Pleiades in the image at left
reveals the 
noticeably
blue color of the stars in the cluster. That is due to
the stars being very young and massive. The more
massive the star is the hotter it is. These stars are
all about twice the temperature of the Sun's 6000 K.
Alcyone, the brightest of the Pleiades has a mass of about 6
Suns, but its luminosity is about 2400 times the
Sun's. That means if Alcyone were in the Sun's
position in the Solar System, the Earth would truly be
scorched! We will feature a better photo of the
Pleiades when the College
View Observatory is completed!
Due to Thanksgiving break there will be no Physics Photo
of the Week next week. Watch for the next photo on
Friday, November 30, 2012. Have a good
Thanksgiving!
Physics Photo of the Week is published weekly during the academic year on Fridays by the Warren Wilson College Physics Department. These photos feature interesting phenomena in the world around us. Students, faculty, and others are invited to submit digital (or film) photographs for publication and explanation. Atmospheric phenomena are especially welcome. Please send any photos to dcollins@warren-wilson.edu.
All photos and discussions are copyright by Donald Collins or by the person credited for the photo and/or discussion. These photos and discussions may be used for private individual use or educational use. Any commercial use without written permission of the photoprovider is forbidden.
Click here to see the Physics Photo of the Week Archive.
