Astronomy Science Olympiad Master Exam Questions And Answers

Astronomy Science Olympiad Master Exam Questions And Answers Optical double - answernot actually binaries simply two stars lying along same line of sight (similar RA & dec) Not gravitationally bound Not usefull in determining stellar masses Visual binary - answerboth stars resolved independently if orbital pd not too long, can monitor motion provides angular separation from center of mass If dist known, linear separations can be calculated Astrometric binary - answerIf one significantly brighter, not possible to see both directly Exitence deduced by observing oscillatory motion of visible member Spectrum binary - answertwo superimposed independent discernible spectra Doppler effect causes shifting of spectral lines Spectroscopic binary - answerif period not too long Orbital motion has component along line of sight Periodic shift in spectral lines observable Only 1 set of periodically varying spectral lines seen Systems able to provide us with mass determination - answerVisual binaries combined with parallax info Visual binaries with radial velocities available over complete orbit Eclipsing double-line spectroscopic binaries O stars - answerHottest blue-white stars with few lines Strong He II absorption (sometimes emission) lines He I absorption lines becoming stronger B stars - answerHot blue-white He I absorption lines strongest at B2 H I (Balmer) absorption lines getting stronger A stars - answerWhite Balmer absorption lines strongest at A), becoming weaker later Ca II absorption lines becoming stronger F stars - answerYellow-white Ca II lines continue to increase, Balmer lines decrease Neutral metal absorption lines (Fe I, Cr I) G stars - answerYellow Solar-type spectra Ca II increase Fe I, other neutral metal increase K stars - answerCool orange Ca II H & K strongest K0, then decrease dominated by metal absorption M stars - answerCool red Molecular absorption bands (TiO, VO) Neutral metal absorption lines remain strong L stars - answerVery cool, dark red Stronger in infrared Strong molecular absorption bands of metal hydrides, water, CO, Na, K, Rb, Cs, Alkalis TiO, VO decrease T stars - answerCoolest, Infrared Strong methane, CO decrease Wolf-Rayet stars - answerdiscovered by C.J.E. Wolf and G. Rayet Paris Observatory in 1867 more than 220 WR identified, most likely more