Astronomy Science Olympiad Master
UPDATED ACTUAL Questions and
CORRECT Answers
Optical double - CORRECT ANSWER✔✔- not 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 - CORRECT ANSWER✔✔- both 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 - CORRECT ANSWER✔✔- If one significantly brighter, not possible to
see both directly
Exitence deduced by observing oscillatory motion of visible member
Spectrum binary - CORRECT ANSWER✔✔- two superimposed independent discernible
spectra
Doppler effect causes shifting of spectral lines
Spectroscopic binary - CORRECT ANSWER✔✔- if 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 - CORRECT ANSWER✔✔- Visual
binaries combined with parallax info
Visual binaries with radial velocities available over complete orbit
Eclipsing double-line spectroscopic binaries
,O stars - CORRECT ANSWER✔✔- Hottest blue-white stars with few lines
Strong He II absorption (sometimes emission) lines
He I absorption lines becoming stronger
B stars - CORRECT ANSWER✔✔- Hot blue-white
He I absorption lines strongest at B2
H I (Balmer) absorption lines getting stronger
A stars - CORRECT ANSWER✔✔- White
Balmer absorption lines strongest at A), becoming weaker later
Ca II absorption lines becoming stronger
F stars - CORRECT ANSWER✔✔- Yellow-white
Ca II lines continue to increase, Balmer lines decrease
Neutral metal absorption lines (Fe I, Cr I)
G stars - CORRECT ANSWER✔✔- Yellow
Solar-type spectra
Ca II increase
Fe I, other neutral metal increase
K stars - CORRECT ANSWER✔✔- Cool orange
Ca II H & K strongest K0, then decrease
dominated by metal absorption
M stars - CORRECT ANSWER✔✔- Cool red
Molecular absorption bands (TiO, VO)
Neutral metal absorption lines remain strong
,L stars - CORRECT ANSWER✔✔- Very 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 - CORRECT ANSWER✔✔- Coolest, Infrared
Strong methane, CO decrease
Wolf-Rayet stars - CORRECT ANSWER✔✔- discovered by C.J.E. Wolf and G. Rayet Paris
Observatory in 1867
more than 220 WR identified, most likely more
25,000 to 100,000 K
losing mass at over 10^-5 Solar masses per year
Wind speeds of 800 to 3000+ kilometers per second
Rapidly rotating
Can have starting masses of under 20 solar masses
No dramatic variability
P Cygni profile - CORRECT ANSWER✔✔- Absorption trough at short-wavelength edge
superimposed on rather broad emission peak
FU Orionis - CORRECT ANSWER✔✔- contain instabilities in circumstellar accretion disk
Results in 0.01 solar masses being dumped
T-Tauri may go through several stages
Herbig Ae/Be - CORRECT ANSWER✔✔- named for George Herbig
spectral type A or B
strong emission lines
2 to 10 solar masses
tend to be enveloped
, much shorter lifetimes
Herbig-Haro objects - CORRECT ANSWER✔✔- contain jets of gas
first discovered in vicinity of Orion nebula by george Herbig & Guillermo Haro in early
1950s
Proplyds - CORRECT ANSWER✔✔- circumstellar disks around stars in Orion Nebula
appear to protoplanetary disks around less than 1million year old stars
Masses more than 2 * 10^25 kg
Wien's law - CORRECT ANSWER✔✔- (Peak wavelength)(Temperature) = 0.002897755
mK
Stefan Boltzmann Law - CORRECT ANSWER✔✔- Luminosity = 4(pi)(radius)^2(stefan-
boltzmann constant)(effective temperature)^4
Stefan-Boltzmann constant - 5.670400*10^-8 W m^-2 K^4
Stellar parallax - CORRECT ANSWER✔✔- d = 1/p" pc
Distance modulus - CORRECT ANSWER✔✔- m-M = 5 log d - 5 = 5 log (d/10pc)
Diffuse molecular clouds - CORRECT ANSWER✔✔- Also known as translucent molecular
clouds
15 to 50 K
n around 5 * 10^8 to 5*10^9 m^-3
M around 3 to 100 solar masses
Several parsecs across
Birth - CORRECT ANSWER✔✔- The life cycle differs between stars depending on their
mass. Normal-mass stars begin in stellar nurseries, and some matter condenses to create a
protostar. This gains more mass until fusion (H -> He) begins, when it becomes a main-
sequence star.
UPDATED ACTUAL Questions and
CORRECT Answers
Optical double - CORRECT ANSWER✔✔- not 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 - CORRECT ANSWER✔✔- both 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 - CORRECT ANSWER✔✔- If one significantly brighter, not possible to
see both directly
Exitence deduced by observing oscillatory motion of visible member
Spectrum binary - CORRECT ANSWER✔✔- two superimposed independent discernible
spectra
Doppler effect causes shifting of spectral lines
Spectroscopic binary - CORRECT ANSWER✔✔- if 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 - CORRECT ANSWER✔✔- Visual
binaries combined with parallax info
Visual binaries with radial velocities available over complete orbit
Eclipsing double-line spectroscopic binaries
,O stars - CORRECT ANSWER✔✔- Hottest blue-white stars with few lines
Strong He II absorption (sometimes emission) lines
He I absorption lines becoming stronger
B stars - CORRECT ANSWER✔✔- Hot blue-white
He I absorption lines strongest at B2
H I (Balmer) absorption lines getting stronger
A stars - CORRECT ANSWER✔✔- White
Balmer absorption lines strongest at A), becoming weaker later
Ca II absorption lines becoming stronger
F stars - CORRECT ANSWER✔✔- Yellow-white
Ca II lines continue to increase, Balmer lines decrease
Neutral metal absorption lines (Fe I, Cr I)
G stars - CORRECT ANSWER✔✔- Yellow
Solar-type spectra
Ca II increase
Fe I, other neutral metal increase
K stars - CORRECT ANSWER✔✔- Cool orange
Ca II H & K strongest K0, then decrease
dominated by metal absorption
M stars - CORRECT ANSWER✔✔- Cool red
Molecular absorption bands (TiO, VO)
Neutral metal absorption lines remain strong
,L stars - CORRECT ANSWER✔✔- Very 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 - CORRECT ANSWER✔✔- Coolest, Infrared
Strong methane, CO decrease
Wolf-Rayet stars - CORRECT ANSWER✔✔- discovered by C.J.E. Wolf and G. Rayet Paris
Observatory in 1867
more than 220 WR identified, most likely more
25,000 to 100,000 K
losing mass at over 10^-5 Solar masses per year
Wind speeds of 800 to 3000+ kilometers per second
Rapidly rotating
Can have starting masses of under 20 solar masses
No dramatic variability
P Cygni profile - CORRECT ANSWER✔✔- Absorption trough at short-wavelength edge
superimposed on rather broad emission peak
FU Orionis - CORRECT ANSWER✔✔- contain instabilities in circumstellar accretion disk
Results in 0.01 solar masses being dumped
T-Tauri may go through several stages
Herbig Ae/Be - CORRECT ANSWER✔✔- named for George Herbig
spectral type A or B
strong emission lines
2 to 10 solar masses
tend to be enveloped
, much shorter lifetimes
Herbig-Haro objects - CORRECT ANSWER✔✔- contain jets of gas
first discovered in vicinity of Orion nebula by george Herbig & Guillermo Haro in early
1950s
Proplyds - CORRECT ANSWER✔✔- circumstellar disks around stars in Orion Nebula
appear to protoplanetary disks around less than 1million year old stars
Masses more than 2 * 10^25 kg
Wien's law - CORRECT ANSWER✔✔- (Peak wavelength)(Temperature) = 0.002897755
mK
Stefan Boltzmann Law - CORRECT ANSWER✔✔- Luminosity = 4(pi)(radius)^2(stefan-
boltzmann constant)(effective temperature)^4
Stefan-Boltzmann constant - 5.670400*10^-8 W m^-2 K^4
Stellar parallax - CORRECT ANSWER✔✔- d = 1/p" pc
Distance modulus - CORRECT ANSWER✔✔- m-M = 5 log d - 5 = 5 log (d/10pc)
Diffuse molecular clouds - CORRECT ANSWER✔✔- Also known as translucent molecular
clouds
15 to 50 K
n around 5 * 10^8 to 5*10^9 m^-3
M around 3 to 100 solar masses
Several parsecs across
Birth - CORRECT ANSWER✔✔- The life cycle differs between stars depending on their
mass. Normal-mass stars begin in stellar nurseries, and some matter condenses to create a
protostar. This gains more mass until fusion (H -> He) begins, when it becomes a main-
sequence star.
