Roughly 3,000 astronomers have descended upon Grapevine, Texas, this week for the 229th annual meeting of the American Astronomical Society, the professional society for astronomers here in the U.S. In addition to astronomers presenting and discussing their research with their colleagues, there are a series of big research findings announced each day at the morning and afternoon press conference.
Here are some highlights from yesterday, day one of the conference.
Fast Radio Bursts
Fast radio bursts (aka FRBs) are rapid pulses of radio emission that continue to baffle astronomers. Lasting just milliseconds (a few 1/1000ths of a second), they have been detected for over ten years now, but we still don’t know exactly what they are or where they come from. Radio telescopes “see” light with wavelengths ranging from 1 mm to 100 km (or, if you prefer, frequencies of 300 kHz to 3kHz) and look like giant satellite dishes. Researchers from the University of California Berkeley used the Very Large Array (VLA) in New Mexico and Arecibo in Puerto Rico to observe a known repeating FRB in the hopes of pinpointing its location on the sky and determining the source object generating the bursts. That object has turned out to be a dwarf galaxy over 2.5 billion light-years away. However, the mystery of FRBs hasn’t been solved yet. We still don’t know what phenomena in the galaxy could be causing them. Theories range from accretion onto the galaxy’s central supermassive black hole to rapidly spinning neutron stars left behind after supernovae. For more on this discovery, check out Leah Crane’s write up over on New Scientist.
A team of astronomers using the Arecibo radio telescope in Puerto Rico and the Jodrell Bank Observatory in the U.K. have discovered two pulsars that don’t pulse for the majority of the time - consequently dubbed “part-time pulsars.” Pulsars are the end stage of life for some high mass stars. They are neutron stars left behind after supernovae explosions that spin rapidly and emit powerful beams of light (akin to celestial lighthouses). During the time these two pulsars were observed though, they were only ON (emitting light) for 30% and 0.8% of the time, respectively. Everything we currently know about pulsars is based on the assumption that they don’t turn on and off, so these new observations imply that there might be many more pulsars out there currently in their “off” phases. Consequently, what else don’t we know about pulsars?!
NASA Discovery Missions
NASA’s Discovery Program announced the selection of two new missions, Lucy and Pysche, that will send spacecraft to asteroids in our solar system in the early 2020’s. Asteroids are essentially left over material from the formation of our solar system and studying their composition can reveal more about their origins and the history of the conditions they have been exposed to (moving closer/farther from the Sun, possible collisions with other bodies, etc). Lucy will be the first mission to focus on Jupiter’s Trojan asteroids, small rocky bodies that exist beyond the main asteroid belt and co-orbit the Sun with Jupiter, leading and trailing the gas giant at what are known as Lagrange points of stable gravitational influence. Psyche will explore the asteroid it’s named after, 16 Psyche, a giant metal body located in the asteroid belt. Most asteroids are not massive enough to be differentiated - with denser materials in their cores and lighter materials at the surface, like Earth. But Psyche is more like one giant dense core and is therefore of interest to physicists and geologist trying to study how the terrestrial planets formed their cores and how something like Psyche might have lost the rest of its rocky outer layers.
Stay tuned for four more days of exciting news from the Universe!