Viranga was a Physics/Aerospace Engineering double major who graduated from Cal Poly Pomona in 2011. In summer 2010, and during the 2010-11 academic year, he worked with Dr. Ben Zuckerman’s group at UCLA searching for Y-brown dwarfs, the coolest sub-stellar objects predicted (but not yet found). Viranga is currently a Ph.D. student at UC Santa Cruz in Planetary Science studying the Moon. He hopes to someday to join the space program as an astronaut. This is his story.
This past summer I began working with Dr. Ben Zuckerman (UCLA), David Rodriguez (UCLA), and others in their group to find Y dwarfs (brown dwarfs), which are predicted to be the coolest (~500 K) substellar objects. (A substellar object is a star-like object whose mass is less than 0.08 solar masses or ~80 times Jupiter's mass, and as a result, its interior cannot sustain nuclear fusion.) Finding these cool brown dwarfs will help complete our understanding of the 'grey area' in defining what is a planet and what is a brown dwarf.
Image from “The Discovery of Brown Dwarfs” by Gibor Basri.
Interestingly, even though brown dwarfs have origins like a star they are about the size of Jupiter (independent of mass). I will continue to work on this project through the current academic year as my physics senior project under the supervision of Dr. Alex Rudolph.
In order to find these Y dwarfs we are looking at Spitzer and ground-based observations of old, nearby, high-proper motion white dwarfs. In the past, many brown dwarfs have been found as companions. Since we are looking for objects that are cool and thus faint, we believe that the best way to find them will be to look for them as companions. Since the white dwarfs are old, their companions will be as well and therefore should have had time to cool to around 500 K. In addition, the white dwarfs (and their predicted companions) when comparing observations from two epochs (~few years apart) can be distinguished from other objects in the field due to their high-proper motions. My goal is to help Dr. Zuckerman, David, and the rest of the group be the first to detect a Y dwarf.