Princeton University

In Search Of: Failed Supernovae

Christopher Kochanek

Failed supernovae, where core collapse leads to the formation of a black hole without an external supernova, have always been one of the possible outcomes when a massive star dies. The observed properties of the dying, progenitor stars, mismatches...

The GeV Sun

Annika Peter

The Sun does not shine at GeV energies on its own power, but because cosmic rays interact with its matter and light. By observing and modeling these interactions in and near the Sun, one may learn about cosmic-ray propagation in the inner...

With current technology, young (<100 Myr) planets can be directly imaged - resolved from their parent star - in the near-infrared with adaptive optics. I will discuss results from such imaging, particularly the four-planet system orbiting HR8799. The outer two planets have been characterized spectroscopically using adaptive optics on the Keck telescope, showing non-equilibrium chemistry as well as evidence of composition enhanced in C/O from the original stellar nebula. The next step in direct imaging is Gemini Planet Imager and its counterparts on other telescopes. GPI is a a facility-class instrument operating on the Gemini South telescope, combining advanced adaptive optics with a coronagraph and near-infrared integral field spectrograph. Almost an order of magnitude more sensitive than current instruments, GPI had first light in November 2013. I will present an overview of the instrument and early science results including the orbit and spectrum of the planet Beta Pictoris b, polarization of the HR4796A circumstellar dust disk, and the status of the 600-star GPI Exoplanet Survey. Finally, I will discuss the potential of the WFIRST/AFTA space telescope for direct exoplanet imaging.

http://www.ias.edu/sns/~seminar/colloquia.shtml

Saturn’s satellite Enceladus displays a bewildering array of thermal activity. I will describe our attempts to understand these phenomena in terms of tidal heating associated with the 2:1 mean motion resonance between Enceladus and Dione. Then I...

The first light of a core-collapse supernova emerges the moment a shock front breaches the stellar photosphere — just after the star has been engulfed by its explosion, and just before it releases its fastest ejecta. Shock emergence is implicated in...