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Observing Very Young Stars with GPI. Quinn Konopacky, Bruce Macintosh, Marshall Perrin, Jenny Patience, et al. Stars younger than the primary GPI sample (<10 Myr) represent an interesting population for planet detection with GPI.
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Observing Very Young Stars with GPI Quinn Konopacky, Bruce Macintosh, Marshall Perrin, Jenny Patience, et al.
Stars younger than the primary GPI sample (<10 Myr) represent an interesting population for planet detection with GPI. • Star forming regions > 100 pc away - non-ideal GPI targets • Scientific payoff of planet detection great • Would reveal planets early in evolution • Allow for potential comparisons to models of planet formation at interesting ages
The brightest stars in young star forming regions are potentially accessible with GPI. • Will not represent statistically complete sample, but physical properties of young planets interesting individually • Age spreads of young clusters often smaller than typical GPI target • Might expect bright, young stars to be analogous to systems like HR 8799 and Fomalhaut 2MASS image of young (~2 Myr) A5 star R Coronae Australis
Using various catalogs, a plausible target list was generated. • Requirement that I < 11 • Initial list culled from Herbig & Bell (1988) catalog • Supplemented with more recent catalogs identifying additional members of southern star forming regions R Coronae Australis Region
Over 100 targets identified in ~7 regions. • Average distance ~150 pc • I-band magnitudes between 7 and 11 • Interesting regions of separation space are probable • 50% known binary fraction in sample
Over 100 targets identified in ~7 regions. • Average distance ~150 pc • I-band magnitudes between 7 and 11 • Interesting regions of separation space are probable • 50% known binary fraction in sample Fomalhaut b HR 8799b Neptune HR 8799d
Sample sources have a range of properties. • Both cTTS and wTTS • Range of spectral types • Bump at K-type likely due to unresolved binarity or misidentification • Some transition disk candidates
Contrast curves and the GPI DST are used to determine what mass of planets are detectable. Fomalhaut b HR 8799b+c • For I < 9 magnitude cases, hot start models: • For star like R Cr Aus (d = 130 pc), possible to detect planets as small as 1 MJ assuming • All undetectable with cold start model I = 9; Distance = 130 pc; Age = 3 Myr Hot Start Models, Fortney et al. 2008
Example of I=9.0 source with DST shows relative ease of detection of HR 8799b-like object. • Used properties of R Cr Aus Star with I~9, H~7.1, Spectral Type = F5 • Possibly visible in individual 30 second exposure Single 30 second exposure
For I~11, magnitude cutoff approximated with DST. • Same level of SNR on companion source ~1-2 mags brighter than I=9 case • Mass limit assuming hot start ~2-3 MJup for these fainter guide stars Single 30 second exposure
Other interesting science can be addressed with this sample. • Young stellar disks • Can investigate transition disk phenomenon Espaillat et al. 2007 Simulated observation of Herbig Ae star HD 141569, courtesy of Marshall Perrin
Other interesting science can be addressed with this sample. • Large mass ratio binaries • Essentially unprobed by multiplicity surveys • Discovery can constrain star formation scenarios and brown dwarf formation scenarios Bate 2009 Hinkley et al. 2010
Summary and Possible Proposal Thoughts • Sufficient very young (age < 10 Myr) are observable with GPI to make for interesting sample • Proposal should be separate from main campaign • Combine with 5-20 Myr sample for more targets? • Thoughts/suggestions welcomed! Chamaeleon I Complex European Southern Observatory/VLT UT1+FORS1