Theory Seminar

Thursday, April 13, 2017

Speaker: Josh Berger

Time: 3:30PM -- 4:30PM

Location: HP4351

Title: Hydrogen Axion Star: Metallic Hydrogen Bound to a QCD Axion BEC

Abstract: As a cold dark matter candidate, the QCD axion may form Bose-Einstein condensates, called axion stars, with masses around 10−11M⊙. In this paper, we point out that a brand new astrophysical object, a Hydrogen Axion Star (HAS), may well be formed by ordinary baryonic matter becoming gravitationally bound to an axion star. We study the properties of the HAS and find that the hydrogen cloud has a high pressure and temperature in the center and is likely in the liquid metallic hydrogen state. Because of the high particle number densities for both the axion star and the hydrogen cloud, the feeble interaction between axion and hydrogen can still generate enough internal power, around 10^13 W×(ma/5 meV)^4, to make these objects luminous point sources. High resolution ultraviolet, optical and infrared telescopes can discover HAS via black-body radiation.