cluster & association members ernst paunzen ifa, vienna
DESCRIPTION
The BRITE HRD Without reddening: M(V) = -5 mag and V = 4 mag => distance = 630 pc -6; 4; ; 4; ; 4; ; 4; ; 4; ; 4; ; 4; 65TRANSCRIPT
Cluster & Association Cluster & Association MembersMembers
Ernst PaunzenErnst PaunzenIfA, ViennaIfA, Vienna
Why consider Clusters Why consider Clusters Members?Members?
Clusters offer astrophysical Clusters offer astrophysical properties “for free”:properties “for free”:
1.1. AgeAge2.2. DistanceDistance3.3. ReddeningReddening
Not depending on any Not depending on any temperature, log g, absolute temperature, log g, absolute magnitude calibrationmagnitude calibration
The BRITE HRDThe BRITE HRDWithout reddening: M(V) = -5 mag and V = 4 mag => distance = 630 pc
-6; 4; 1000-5; 4; 630-4; 4; 400-3; 4; 250-2; 4; 160-1; 4; 100+0; 4; 65
Clusters within 750 pcClusters within 750 pc-6; 4; 1000-5; 4; 630-4; 4; 400-3; 4; 250-2; 4; 160-1; 4; 100+0; 4; 65
log t < 8.0 (blue)log t < 9.0 (yellow)log t > 9.0 (red)
Several Cluster Members in the BRITE sample!
WEBDA: http://www.univie.ac.at/webda
Cluster Properties and Cluster Properties and MembershipMembership
Cluster formation within a few Cluster formation within a few MyrsMyrs
From one large Molecular CloudFrom one large Molecular Cloud Membership criteria due to proper Membership criteria due to proper
motions and radial velocitiesmotions and radial velocities
Isochrones IIsochrones I
Padova Isochrones
Isochrones IIIsochrones II
280KHuge Errors!
Lines of Equal MassesLines of Equal Masses2.
5 m
agError:M(V) = 0.1 magMass = 0.1 M(sun)
+ Error in log Teff
Padova Isochrones
Precision of Age DeterminationPrecision of Age Determination
Values from the Literature Paunzen & Netopil, 2006, MNRAS, 371, 1641
Why consider Clusters Why consider Clusters Members?Members?
Clusters offer astrophysical Clusters offer astrophysical properties “for free”:properties “for free”:
1.1. Age, error about 15%Age, error about 15%2.2. Distance, error less than 10%Distance, error less than 10%3.3. Reddening, error less than 5%Reddening, error less than 5%
Values can be improved!Values can be improved! ““Only positive membership needed” Only positive membership needed” Precise mass estimation possiblePrecise mass estimation possible Huge data base (WEBDA) in ViennaHuge data base (WEBDA) in Vienna