The Color-Magnitude Diagram for local stars from Hipparcos Absolute Magnitude Main Sequence Red clump Red Giant Branch (RGB) White dwarfs Kovalevsky 1998 Color
Lebreton 2001 The Hipparcos H-R Diagram of 34 nearby stars
CMD of a globular cluster (Krauss & Chaboyer 2003) Blue Asymptotic Giant Branch Red Horizontal Branch Extreme (blue) Horizontal Branch
Lebreton 2001 Deriving ages from color-magnitude diagrams: The Hyades Cluster
Open clusters from WIYN (Grocholski & Sarajedini 2003) Relative open cluster ages 5.4x10 8 yr Open clusters from Sandage (1958) 1.5x10 8 yr 6.0x10 8 yr 1.1x10 9 yr 1.7x10 9 yr 4.0x10 9 yr
Ages from GC CMDs: 47 Tuc (Schiavon et al. 2002) Note that neither set of isochrones match the RGB and the MS turn-off simultaneously!
Relative ages of globular clusters: two populations
Cleaning globular cluster CMDs: finding the H-burning limit Proper motions of NGC 6397 stars using WFPC2 on HST (King et al. 1998)
Cleaning cluster CMDs: finding the end of the WD cooling sequence Proper motions of M67 stars using groundbased cameras (Bellini et al. 2010)
Do models match real stars? Hipparcos H-R diagram vs. models Solar Z: Low Z: Yes! No! Lebreton 2001
Lebreton 2001 Need something else: diffusion (sedimentation) of He and heavier elements
Lebreton 2001 Deriving ages from color-magnitude diagrams: The Hyades Cluster
Open clusters from WIYN (Grocholski & Sarajedini 2003) Relative open cluster ages 5.4x10 8 yr Open clusters from Sandage (1958) 1.5x10 8 yr 6.0x10 8 yr 1.1x10 9 yr 1.7x10 9 yr 4.0x10 9 yr
Ages from GC CMDs: 47 Tuc (Schiavon et al. 2002) Note that neither set of isochrones match the RGB and the MS turn-off simultaneously!
Relative ages of globular clusters: two populations
M32: CMD 16 Monachesi et al. Monachesi et al. 2010 F6 F4 F2 F3 18 F1 Monachesi et al. F5 F555W the contrary, metal-rich isochrones do a better job in matching both the bright and faint end of the RGB. As stated ear 2 lier, an age-metallicity degeneracy is present in this region of the CMD, and therefore differences in ages cannot be distin 1.5 guished if we look solely at the RGB. To obtain the metallicity distribution function (MDF) of 1 M32, shown in Figure 15, we have counted stars in the decontaminated CMD between fixed-age isochrones covering a 0.5 wide range of metallicities. Isochrones are taken from the model grid of the Padova library (Girardi et al. 2002; Marigo 0 et al. 2008; et al. 2008) for ages of 5, 8 and 10 Gyr ur two HST ACS/HRC pointings: M32 (F1) field and M31 background (F2) field, both indicated as red small boxes. EachGirardi field covers 2 on the sky. The field F1 is located at 110 from the nucleus of M32 and represents the best compromiseand log(z/z ) = [M/H] between minimizing image from 1.2 to 0.3 dex with a metallicity step (bin size) inof [M/H] = 0.2 dex. Although we do on from M31. The F2 field is0.5 at the same isophotal level in M31 corresponding to the location of the F1 field. Thirty-two exposures d F555W (V ) filters were taken for each field. The location of fields F3, F4, F5 and F6 is also shown. They archival notaresee the 5HST/WFPC2 Gyr MSTO7, it is possible that M32 contains analyzed in the Appendix to investigate the presence of a blue plume. Information about these observations can be found in Table 6. 1 such a population due to the observation of bright AGB stars he left. that confirm the presence of an intermediate-age population ely use the deconvolved photometry for of the process, sinc-function interpolation usedfor to shift 1.5 (Sec. was 5.1.4). the metallicity distribution, we have first MD. the PSFs and their component stars as considered needed. only stars located below the RC and above the The Lucy-Richardson algorithm works quickly 80%iteratively, completeness level to avoid contamination by AGB stars 2 removing the wings of the PSFs, but taking considerably that ascend from the RC, generating a loop in the theoretnvolved IMAGE photometry longer to enhance structure on the scaleical of the central diffracisochrones above the RC. We selected a box contain2.5 deconvolved images of F1 and F2 were tion cores. In the present case, we used 640 stars iterations on ing 1166 of magnitudes 1.2 < MF555W < 1.8 and colardson algorithm (Lucy 1974; Richardthe F555W images and 160 iterations on the F435W images. ors 0.7 < (F435W F555W )0 < 1.4 to compute the MDF be3 Fs for the F435W and F555W images This heavy level of deconvolution nearly the im-these stars guarantees an unambiguous low transforms the RC. Selecting ractively and iteratively 0.5 by summing 0 the 0.5 into a set 1 of delta1.5 ages functions, but inmetallicity doing so serves to split but, even though stars in this region of assignment olated stars in the images to produce ad F435W!F555W closely blended stars; pairs of stars asthe close as 0. 03 were CMD have small photometric errors, they are not negligie then used to clean out the fainter stars
Age spreads in clusters: the Taurus-Auriga star-forming region Cohen & Kuhi (1979): ages from 10 4 to 10 7 yrs (similarly for Orion)
Age spreads in star-forming regions: the Upper Scorpius OB association Preibisch et al. (2002): Age around 5 Myr, very small (<2 Myr) scatter
The Mass-Luminosity Relation of the Hyades Cluster from Hipparcos
The (initial) mass function of the Upper Sco OB association Preibisch et al. (2002)
Cleaning globular cluster CMDs: finding the H-burning limit Proper motions of NGC 6397 stars using WFPC2 on HST (King et al. 1998)
Berger et al. 2006 Mass-radius relation for nearby, low-mass dwarf 0.8 stars 0.7 Radius (solar units) 0.6 0.5 0.4 0.3 0.2 0.1 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Mass (solar units) Fig. 4. The mass radius relation for low-mass dwarfs measured by long-baseline interferometry (filled symbols) and spectrophotometry of eclipsing binaries (open circles, see references in 1). The interferometry data included are from this paper (circles), PTI (Lane et al. 2001, triangles), and VLTI (Ségransan et al. 2003, squares). The lines represent models from Chabrier & Baraffe (1997) for different metallicities ( for [M/H]= 0.0; - - - - for [M/H]= 0.5; for [M/H]= 1.0) and Siess et al. (1997) for similar metallicities ( for [M/H]= 0.0; for [M/H]= 0.3).
Solar (near) surface rotation: differential rotation! P=25 days P=36 days
Stellar Rotation: spin-down with age 100 Myr Soderblom, Jones & Fischer (2001) 220 Myr 250 Myr 650 Myr
Things we still don t understand: the second parameter effect CMDs from Rey et al. (2001). [Fe/ H]=-1.7 for both clusters; note different HB morphologies. Relative age dating from Johnson & Bolte (1998) not age? Recent work (Gratton et al. 2010) suggests age and He content play a role