Session Number
U839
Advisor(s)
Don York, University of Chicago
Location
Lecture Hall
Start Date
28-4-2016 10:15 AM
End Date
28-4-2016 10:40 AM
Abstract
The interstellar medium is full of cool clouds, around 100°K, made of atoms, molecules, and dust particles. Mysterious components of these clouds are carriers of diffuse, unidentified interstellar bands (DIBs). Because they are too broad to be caused by atoms, they are thought to consist of over 400 nonterrestrial molecules. I tried to observe the behavior of DIBs around the isolated cloud, MBM12, using absorption lines in spectra of background stars. Suitable stars were picked from a database accumulated at the University of Chicago. Spectra were examined using a piece of analysis software, arcexam, written by Dan Welty, that compares wavelength and flux of two stars. I measured 90 lines in the six stars behind the cloud. Probing mainly the edges of the cloud, I found that two DIBs were exceptionally strong compared to their strengths in the other stars in the galaxy. More observations of fainter stars, buried in dust at the cloud center, will be necessary to understand the DIBs more fully. I have demonstrated that this cloud is ideal for such studies. It was found that many of the DIBs that are common in foreground and background stars were usually twice as strong in the background stars.
Measurements and Comparisons of Diffuse Interstellar Bands around the MBM12 Interstellar Cloud
Lecture Hall
The interstellar medium is full of cool clouds, around 100°K, made of atoms, molecules, and dust particles. Mysterious components of these clouds are carriers of diffuse, unidentified interstellar bands (DIBs). Because they are too broad to be caused by atoms, they are thought to consist of over 400 nonterrestrial molecules. I tried to observe the behavior of DIBs around the isolated cloud, MBM12, using absorption lines in spectra of background stars. Suitable stars were picked from a database accumulated at the University of Chicago. Spectra were examined using a piece of analysis software, arcexam, written by Dan Welty, that compares wavelength and flux of two stars. I measured 90 lines in the six stars behind the cloud. Probing mainly the edges of the cloud, I found that two DIBs were exceptionally strong compared to their strengths in the other stars in the galaxy. More observations of fainter stars, buried in dust at the cloud center, will be necessary to understand the DIBs more fully. I have demonstrated that this cloud is ideal for such studies. It was found that many of the DIBs that are common in foreground and background stars were usually twice as strong in the background stars.