photometric bin Flashcards
what are photometric bin?
role of inclination
EA, EB, EW
eclipsing ALgol type: no contact
eclipsing beta lyrae type: contact
eclipsing W Ursae Majoris type: contact bin w CE
prob with ground based obs?
AM
reddening
advantage of ground based obs?
cheap
solution to AM?
comparison star see if variablity is same
conditions fro comparison star?
close by
similar temp
same color (to same reddening effect)
other uses of photometric analysis
exoplanet
asteriod
telescopes observing for photometric analysis?
problem w space based obs.
expensive (data transfer, fewer missions)
light reflection
cosmic rays
parameters derived
roche potential from mass ratio
types od attachment
detached
contact
overcontact
effect of tidal interactions?
circular orbits
synchronised rotation
how different lightcurve effects help derive orbital parameters?
lc variation w orbital period fro ref, ellipsoid?
ref– sine– orbital period
ellipsoid sine– orbital period / 2
parametres info from ellipsoid
ellipsoid deformation is based on tidal forces, roche geometry:
q– deformation (obs in lc) propotional to mass ratio
a– semi major axis inv propotional to distortion
R
what is Gravity darkening
tidal forces or fastrotation can make equator more stretched out, T_pole> T_equator
what do limb darkening and gravity darkening look like in lc?
limb darkening – rounded curve in eclipse minima
what lc effect grav darkenig can be obs with?
ellipsoidal effect
what is Gravitational lensing & Gravitational self-lensing ?
gravitational lensing, why flux inc? why lc top curve rounded?
ellipsoid– why sinosidal variations are asymmteric?
relatistiv beaming
in space based missions– flux amplified for blue-shifted. asymmetric amp–
sd + wd
which lc variation effect produces diagnostic parameters ?
which dont?
Do:
eclipses: R
relatistic beaming: lc -> R_V
ellipsoid (q, R/a)
Don’t:
grav lensing?
reflection?
effcts that cause change in eclipses?
romers delay
rositter mc laugllin effect
romers delay
diff masses– slight different dist to observer- slight shift in time light reaches us
rositter mclauglin effect
brcause of rotation– some part of star is blushifted and other red– eclipses in blue n red shifted part– effects spectra– radial velocity
when is rositter mclaughlin effect more prominent?
fast rotation– far from the center
use of rositter mclaughlin effect
more useful for eclipse not at the center
when eclipses are not in the orbital plane (misaligned) eclipse not in the center –
discovery of exoplanets (un aligned, retrogate)
young massive stars otherwise are difficult to find paramters because of rotatinal broadening
identify rositter mclaughlin effect in radial vel curve?
for: blueshifted
redshifted
retrograde
can you measure mass ratio from romers delay? how?
yes, del t = cont. x K (1- m2/m1)
parameters observable for eclipsing binaries?
info of all parameters –
inclination, distance = astrometry
mass = spectra
radius = eclipse
how are double line eclipsing binaries amazing?
sine lc?
ref or ellipsoid?
diff between ref or ellipsoid?
period
ref vary by p
ellipsoid vary by p/2
how does romer delay help identify masses?
how does ellipsoidal help put constraints on inclination?
lc dependednt on R/a, q and inclination
how are gravitational lensing and self gravitational lensing identified in lightucurves?
anti transit or shallower eclipses than estimated
use of gravitational lensing?
flux ratio proportional to M2/R1?
use of relativistic doppler beaming?
lc –> radial velocity curve –> orbital parameters
cheaper than spectra
