LA JOLLA, Calif. (nasa) – A high-school student teamed up with a professional astronomer to make observations of the remains of a star explosion with NASA’s Rossi X-ray Timing Explorer (RXTE) spacecraft.
Harish Khandrika, an 11th grade student at La Jolla High School, La Jolla, Calif., joined Dr. Richard Rothschild of the University of California, San Diego, to make the observations, winning a series of awards at the Greater San Diego Science and Engineering Fair and the Intel International Science and Engineering Fair, Louisville, Ky.
Khandrika, whose room is plastered with posters of stars and planets, channeled his curiosity about space into an award- winning science fair project by reaching out to astronomers at the local university. “I am very passionate about studying the universe,” said Khandrika. “Last summer, I knocked on the doors of scientists at the Center for Astrophysics and Space Sciences (CASS) at the University of California, San Diego, to ask if anyone would be kind enough to let me work in his or her laboratory. I expressed my interest in supernovae and black holes to Dr. Gene Harding Smith, who directed me to Dr. Rothschild. It was Dr. Rothschild who suggested I look at data from RXTE.”
Star explosions, called supernovae, can outshine a billion Suns, and are intimately connected to our origin since they create and/or distribute life-sustaining elements into space. A supernova hurls trillions of tons of elements into space in an enormous cloud, called a supernova remnant. These elements are incorporated into later generations of stars and planets, and, ultimately, life.
Khandrika used RXTE to look for gamma rays emitted by radioactive Titanium (Ti-44) in supernova remnant Cassiopeia A. Ti-44 changes into other elements relatively quickly by radioactive decay, so its presence in a supernova remnant indicates that the star must have exploded recently. (Half a given amount of Ti-44 will change into Scandium in about 59 years.) Khandrika established that the Ti-44 in Cassiopeia A could not be above a certain amount, or its gamma-ray emission would have been seen by RXTE.
The upper limit is consistent with an actual detection made by other researchers during the same period using Beppo SAX, an Italian spacecraft. The results indicate that the supernova produced an amount of Ti-44 about equal to 40 times the mass of the Earth, and that during the supernova, the star’s core should have collapsed to form a neutron star, an incredibly dense sphere with the mass of about half a million Earths compressed to the diameter of a large city.
Khandrika enjoyed his research experience tremendously, and hopes to become an astronomer. “I just loved it. I enjoyed my work at CASS. It was a pleasure working with Dr. Rothschild. He provided a lot of motivation and inspiration for me. I am very happy that the work was recognized too. I hope to pursue graduate studies in space sciences and be a space scientist, trying to understand my place in this awesome vast expanse. Maybe one day I will work for NASA!”
“I enjoyed working with Harish, who is a very motivated and inquisitive student,” said Rothschild. “He worked very independently, gathering information on stellar formation, supernova events and remnants from the Web and from books loaned to him. I was very impressed with his level of understanding and his curiosity. We have begun a second project for this summer — this time emission from a massive black hole at the center of the active galaxy NGC 529A.”
Khandrika’s project received lots of attention at the San Diego science fair, where it earned him the Sweepstakes Award, First Place in Earth and Space Sciences, the San Diego Astronomy Association Award, the Mt. Laguna Observatory Association award, the General Atomics Fusion award and the Hughes Network Systems award.
At the San Diego science fair, two senior division projects are selected as best-of-fair projects (selected from the best in each category) to receive the Sweepstakes Awards and to represent the county at the Intel International Science and Engineering Fair. The award includes a $2000 scholarship from the Reuben H. Fleet Science Center, San Diego.
Khandrika’s success at the San Diego science fair led him to the Intel science fair, where he won another award, the American Astronomical Society (AAS) and the Astronomical Society of the Pacific (ASP) Priscilla and Bart Bok Second Award.
The Priscilla and Bart Bok Award is presented annually by AAS and ASP for two outstanding astronomical projects at the International Science and Engineering fair. The second award consists of a $3,000 scholarship, and the student’s school science department receives $1,000. Support for this award has been provided by a grant from the National Science Foundation.
