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The Stellar Population of the Chamaeleon I Star-forming Region
| Content Provider | Semantic Scholar |
|---|---|
| Author | Luhman, K. L. |
| Copyright Year | 2008 |
| Abstract | I present a new census of the stellar population in the Chamaeleon I star-forming region. Using optical and near-IR photometry and followup spectroscopy, I have discovered 50 new members of Chamaeleon I, expanding the census of known members to 226 objects. Fourteen of these new members have spectral types later than M6, which doubles the number of known members that are likely to be substellar. I have estimated extinctions, luminosities, and effective temperatures for the known members, used these data to construct an H-R diagram for the cluster, and inferred individual masses and ages with the theoretical evolutionary models of Baraffe and Chabrier. The distribution of isochronal ages indicates that star formation began 3-4 and 5-6 Myr ago in the southern and northern subclusters, respectively, and has continued to the present time at a declining rate. The IMF in Chamaeleon I reaches a maximum at a mass of 0.1-0.15 M ⊙ , and thus closely resembles the IMFs in IC 348 and the Orion Nebula Cluster. In logarithmic units where the Salpeter slope is 1.35, the IMF is roughly flat in the substellar regime and shows no indication of reaching a minimum down to a completeness limit of 0.01 M ⊙. The low-mass stars are more widely distributed than members at other masses in the northern subcluster, but this is not the case in the southern subcluster. Meanwhile, the brown dwarfs have the same spatial distribution as the stars out to a radius of 3 • (8.5 pc) from the center of Chamaeleon I. The characteristics of the distributions of masses, ages, and positions in a newborn stellar population are determined by the process of star formation. As a result, measurements of these distributions in star-forming regions are potentially valuable for testing models of the birth of stars and brown dwarfs. For instance, the properties of the stellar initial mass function (IMF, Meyer et al. 2000) can constrain the relative importance of turbulent fragmentation (Padoan & Nordlund 2002), gravita-tional fragmentation (Larson 1985), dynamical interactions (Bonnell, Bate, & Vine 2003), and accretion and outflows (Adams & Fatuzzo 1996) in regulating the final masses of stars. Models of the star formation rates of molecular clouds (e.g., constant, accelerating, bursts) can be tested against the distributions of ages and positions of members of young clusters (Feigelson 1996; Palla & Galli 1997; Hartmann 2001). The spatial distributions also provide insight into cloud fragmentation, binary … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0710.3037v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Bethe–Salpeter equation Bonnell (microarchitecture) Censuses Cloud computing Diagram Dwarfism Fourteen Fragmentation (computing) GUCY2C protein, human Infant, Newborn Inference Interaction Physical object Pipelines Stars, Celestial Stellar (payment network) Turbulence |
| Content Type | Text |
| Resource Type | Article |
