bin pop

Question 1

ultra wide viaul binaries? how confirmed as binaries

Answer 1

distance to us
same proper motion, comoving motion

Question 2

imortance of stufying surius

Answer 2

sirirus is a well studied wd– imp for callibration of wd

Question 3

fun fact: for some reflection effects, eg AA Dor
Close hot subdwarf OB star with M-dwarf companion: Analysis similar to a double-lined binary possible because of strong reflection

Question 4

Binary populations: Statistical models: can have selection bias. based on stars that are studied, sample, projection and contaniments

Question 5

what is Binary fraction on the
main sequence depends
on ?

Answer 5

stellar mass
for HMS ~80%

Question 6

explain why most HMS are in binaries?

Answer 6

formation in large gas cloud, HMS remained close to the center while LMS scatter

Question 7

binary fractions in old and dense globular clusters?

Answer 7

dense env, destruction of bin– lower bin frac

Answer 8

mass transfer among binaries changes the nature of binaries
can leave a trace on the companion

Question 9

example of effect of evo on blue straggler

Answer 9

blue str = MS stars too massive or blue for old cluster
rejuvination explnations: single: merger
binary: mass transfer
evidence of both found

Question 10

evidence of AGB companion

Answer 10

elemnts found in these stars are only producded by AGB
e.g CH, S, Barium stars

Question 11

AM type in binary

Answer 11

MS A-F type
slower rotation than MS due to tidal braking
heavy elements enrichment due to slower rotation