Izbrane teme sodobne fizike in matematike

Kataklizmične spremenljive zvezde

V članku so predstavljene kataklizmične spremenljivke, ki so primer kratkoperiodičnih dvozvezdij. Najprej je opisana geometrija sistema in njegov časovni razvoj, ki ga določa prenos mase med zvezdama. Nato sta razložena primera nekonservativnega razvoja, pri katerem se vrtilna količina sistema izgublja preko sevanja gravitacijskih valov in magnetnega zaviranja. Nato sledi pregledna razlaga akrecijskega diska. Zadnji dve poglavji se osredotočata na dva pojava, ki sta povezana s kataklizmičnimi spremenljivkami - klasične nove, pri katerih se izsev sistema skokovito poveča zaradi termonuklearne eksplozije vodikove plasti na beli pritlikavki, in pritlikave nove, pri katerih se izsev akrecijskega diska periodično spreminja zaradi spreminjanje njegove strukture in temperature.

Cataclysmic variable stars

Cataclysmic variables are an example of short period binary stars. First the geometry of the system is discussed along with its time evolution which is determined by the mass transfer between the stars. Then follows the explanation of the non-conservative evolution where the system’s angular momentum is lost by radiation of gravitational waves and magnetic braking. Later is an overview of accretion disks and the last two chapters focuse on two phenomena connected to cataclysmic variables — classical novea where the luminosity of the system is abruptly increased because of thermonuclear explosion of hydrogen layer on the white dwarf; and dwarf novea where the luminosity of the accretion disk periodically varies due to its varying structure and temperature.