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Distance not an Obstacle for Grace

8/08/2014

Grace Lawrence outside
'The Commonwealth Solar
Observatory Building'

Most students use rulers, tape measures or even data-loggers to measure distances in their everyday day lives, but Senior Astrophysics student Grace Lawrence prefers to use a measuring device not too many of us are aware of; or even heard of – Cepheids!  Cepheid variable stars are extremely luminous stars that “pulsate” over a period of several days.  There is a fascinating relationship between the star’s ‘luminosity’ and ‘pulsation period’ which allows astrophysicists to use some handy mathematical methods to determine their distance from us, and hence the distance to the galaxy they are in.  Grace was introduced to this unique method at the Australian National University’s “Research School of Astronomy and Astrophysics” (ANU-RSAA) after being selected as one of only two students that would be given the opportunity to work alongside RSAA professional astrophysicists and PhD students as part of their mid-year professional experience program.   

For 5 days, Grace had the opportunity to work with some of the latest data captured by the Hubble Space Telescope (HST) from a galaxy known as Messier 82 (NGC 3034), or commonly referred to as the Cigar galaxy, somewhere in the vicinity of 12 million light-years distant.  After becoming familiar with the data, Grace identified various Cepheids and used mathematical and error analysis methods to predict the distance to galaxy M82 – a task only performed by two other professionals before her. 

After delivering a ‘daunting’ presentation of her findings to a host of RSAA and visiting astrophysicists on her final day, Grace was relieved to learn that her distance prediction was thought to be extraordinarily close.    

Other highlights of the week for Grace were eating pizza with Prof Brian Schmidt, attending a supernova tea, attending colloquiums to hear specialists explain their cutting-edge research and learning how to carry out professional research.  Grace would particularly like to thank Dr Brad Tucker for all of his professional assistance and to all of the RSAA staff who made her feel very welcome.