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Exoplanet Science Strategy (2018) / Chapter Skim
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Appendix C: Exoplanet Detection Methods
Pages 148-154

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From page 148...
... For a circular orbit, the general observables periastron and the systemic velocity ofperiod (as wellForthecircular periastron radial velocity curve as a the stellar velocity semiamplitude K and the the system)
From page 149...
... For exoplanetsone ofnearly edge-on the planet passesexoplanets, asof circular orbits w specifically in In as it in the casetransit blocking when the impact of stellar in units of theto detect between the simplest techniques stellar radius satisfies specifically the observer on the the case ofhost a small amount ofthe with nearly edge-on passesof the stellar observer and the specifically in planet blocking star.orbits when stellar lightparameter in inclinations, orthe radius satisfies it relies and the planet's circular For exoplanets impact as the planet units betweeninequality the more the inequality the inequality For exoplanets with when the impact parameter in units of the in the radius satisfies 𝑏𝑏𝑏𝑏 ≦ Eβˆ— 1 + π‘˜π‘˜π‘˜π‘˜ ,, ≦ B CD2 5 1 + specifically in the case of circular orbitsnearly edge-on inclinations, or more specificallystellar case of circular orbits planet's host star. B CD2 5 the inequality impact parameter in units of the stellar radius satisfies the inequality when the 𝑏𝑏 ≦ 1 + π‘˜π‘˜ , B CD2 5 Eβˆ— where π‘˜π‘˜ = E0 where π‘˜π‘˜ E= p Eβˆ—, the planet will pass in front of its parent star (transit)
From page 150...
... the angular separation of a planet the its host star much brighter the Keplerian orbital elements, observation and for e.g., the the distance the thermal For B , where d is Detectingseparationonviaplanet from its hostplanet from its on resolving the light For simplicity, one assumes a as well as Detecting exoplanetsangular separation ofgenerally refers host star depends on allfrom an orbiting The via direct imaging a star depends to all to Keplerian the Keplerian orbital elements, The angular as well as of a epoch of observation and the to resolving the light orbital elements, exoplanets thedirect imaging generally refersdistancethe the system.from an orbiting which the angular separation is simply , where flux ratio dependsthe the geometric albedo Ag, the Z m eclipse spectroscopy)
From page 151...
... Consider an mature planets orbiting a Sun-like star at a distancehost stars via either reflected ratio Directly detecting Earth analogue that are in equilibrium with their from Earth of 10 pc. The flux light or reprocessed thermal emission is generally much harder, and is expected to require space-based light of Earth to thesimply reflected light (depending on albedo and phase)
From page 152...
... The durations thethe primary microlensingevents are 𝑑𝑑𝑑𝑑r = xUyz ,,,where πœ‡πœ‡πœ‡πœ‡RKt is xtherelative proper motion o solar-mass star.The durations of of primary microlensing events are r = whichis typically aawhichAUto 5 AU aforhost AU forwithmasses ofmasses of the mass ofmass of a typical Mof a typical M dwarf few is typically a few to 5 stars host stars with roughly roughly the typical mass dwarf to a solar-mass v hich is typically which is typically for hoststars5 AU for host ofroughly masses ofofaatypical M dwarf AU to 5 AU for hostis solar-mass few AUroughly theof the starstypical M dwarfvww which a typicallymasses Theto 5 AU formass of a with masses of roughly the mass ofwa , where M dwarf dwarf where r isthe RKt The events are = x , where πœ‡πœ‡RKt is the durations of the a solar-mass star.motion between 𝑑𝑑the lens and source, which events xUyz are 𝑑𝑑 =RKtwis, the where πœ‡πœ‡RKt is the vw where v Uyz to The durations of the primary microlensing to primary microlensing durations ofrthe primary microlensing is typically r events are Uyz elative proper motion betweenthe and and source, which is typically 5-10 milliarcseconds peryear, the relative proper lens and source, is typically 5-10 milliarcseconds per year, and year, and between the the 5-10xmilliarcseconds durations of elative proper motion between lens lens source, whichwhich is typically 5-10 milliarcseconds perUyzthus and typicalper year, and tween the lens durations oftypical durations of5-10 milliarcsecondsfewdaysoftohundreds ofmilliarcseconds per days. and relative propermicrolensing events due atostars events duedaystodays.
From page 153...
... Fortunately, the signals induced from these planets are typically large and unambiguous, unless the angular Einstein ring radius of the planet is substantially smaller than that of the angular size of the source, which generally occurs only for planets less massive than Earth. Because of the low probability of detecting a stellar-mass microlensing event, and the lower probability of detecting the planetary perturbation even in the case that the microlensing event is detected153 APPENDIX C and assuming the planetary companion exists, microlensing surveys for exoplanets generally require continuously monitoring hundreds of millions of stars on daily time scales to detect the microlensing events, and then monitoring theare typically large and unambiguous, unless the angular scales to ring radius of the induced from these planets known microlensing events on hourly to daily time Einstein detect the planetary perturbations.
From page 154...
... values for exoplanets with MT sin(i) determined from radial velocity data.


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