A Census of the Chamaeleon I Star-forming Region

By K. Luhman. 2004

173 citations recorded by the source corpus.

I present a new census of the members of the Chamaeleon I star-forming region. Optical spectroscopy has been obtained for 179 objects that have been previously identified as possible members of the cluster, that lack either accurate spectral types or clear evidence of membership, and that are optically visible (I ≲ 18). I have used these spectroscopic data and all other available constraints to evaluate the spectral classifications and membership status of a total sample of 288 candidate members of Chamaeleon I that have appeared in published studies of the cluster. The latest census of Chamaeleon I now contains 158 members, eight of which are later than M6 and thus are likely to be brown dwarfs. I find that many of the objects identified as members of Chamaeleon I in recent surveys are actually field stars. Meanwhile, seven of nine candidates discovered by Carpenter and coworkers are confirmed as members, one of which is the coolest known member of Chamaeleon I at a spectral type of M8 (~0.03 M☉). I have estimated extinctions, luminosities, and effective temperatures for the members and used these data to construct an H-R diagram for the cluster. Chamaeleon I has a median age of ~2 Myr according to evolutionary models and hence is similar in age to IC 348 and is slightly older than Taurus (~1 Myr). The measurement of an initial mass function for Chamaeleon I from this census is not possible because of the disparate methods with which the known members were originally selected and must await an unbiased, magnitude-limited survey of the cluster.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/25f262884acbbbcb8647261b8be56d71d01fe95f

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

The Disk Population of the Chamaeleon I Star-forming Region (2008, methodology): “The group appears to have an age of ∼ 6 Myr and a distance of d ≃ 114 pc (Feigelson et al. 2003; Luhman 2004b).”
X-Shooter study of accretion in Chamaeleon I (2015, methodology): “The sample of pre-main sequence (PMS) stars presented in this study was selected from Luhman (2004, 2007), Spezzi et al. (2008), and Alcalá et al. (2008) and has been observed with X-Shooter (Vernet et al. 2011) on the Very Large Telescope (Paranal, Chile) between January 17 and 19, 2010.”
The Stellar Population of the Chamaeleon I Star-forming Region (2007, methodology): “Minimum Mass To date, measurements of IMFs in nearby star-forming regions have reached mass limits of ∼ 0.005-0.02 M⊙ through luminosity function modeling (Luhman et al. 2000; Hillenbrand & Carpenter 2000; Muench et al. 2002, 2003; Preibisch et al. 2003; Lucas et al. 2005) and spectroscopy (Hillenbr”
Characterizing Young Brown Dwarfs Using Low-Resolution Near-Infrared Spectra (2006, methodology): “The published AV value for Cha H 11 (AV ¼ 0:3; Luhman 2004) might be underestimated, and an AV of 0.2 for an unreddened object is well within our uncertainty of AV 0:5.”
The T Tauri Phase Down to Nearly Planetary Masses: Echelle Spectra of 82 Very Low Mass Stars and Brown Dwarfs (2005, methodology): “…Hartigan et al. 1994; Martı́n et al. 1994; Mathieu 1994; Kenyon et al. 1998; Monin et al. 1998; Briceño et al. 1998, 1999; White & Hillenbrand 2004; IC 348, Luhman et al. 2003b; Cha I, Luhman 2004; Upper Sco, Walter et al. 1994; Preibisch et al. 1998, 2002) and applied the BM03 accretion criteria.”
Inverse dynamical population synthesis: Constraining the initial conditions of young stellar clusters by studying their binary populations (2012, background): “Taurus was originally proposed to be deficient in lowmass stars (Briceño et al. 2002), but many brown dwarfs have since been discovered (Luhman 2004b; Guieu et al. 2006).”
New Brown Dwarfs and an Updated Initial Mass Function in Taurus (2004, methodology): “Following Luhman (2004), this reddening is quantified by the color excess between 0.6 and 0.9 m, denoted as E(0:6 0:9) in Figures 3 and 4.”
AN INFRARED/X-RAY SURVEY FOR NEW MEMBERS OF THE TAURUS STAR-FORMING REGION (2009, methodology): “Meanwhile, the XEST fields have been fully covered at optical and near-IR wavelengths by either deep wide-field imaging (Briceño et al. 2002; Luhman 2004c; Guieu et al. 2006) or all-sky catalogs (Luhman 2006), which have produced a high level of completeness for classes II and III between 0.1-0.02…”