A Census of the Young Cluster IC 348

By K. Luhman, J. Stauffer, August Muench, G. Rieke, E. Lada, J. Bouvier, C. Lada. 2003

492 citations recorded by the source corpus.

We present a new census of the stellar and substellar members of the young cluster IC 348. We have obtained images at I and Z for a 42′ × 28′ field encompassing the cluster and have combined these measurements with previous optical and near-infrared photometry. From spectroscopy of candidate cluster members appearing in these data, we have identified 122 new members, 15 of which have spectral types of M6.5-M9, corresponding to masses of ~0.08-0.015 M☉ by recent evolutionary models. The latest census for IC 348 now contains a total of 288 members, 23 of which are later than M6 and thus are likely to be brown dwarfs. From an extinction-limited sample of members (AV ≤ 4) for a 16′ × 14′ field centered on the cluster, we construct an initial mass function (IMF) that is unbiased in mass and nearly complete for M/M☉ ≥ 0.03 (≲M8). In logarithmic units where the Salpeter slope is 1.35, the mass function for IC 348 rises from high masses down to a solar mass, rises more slowly down to a maximum at 0.1-0.2 M☉, and then declines into the substellar regime. In comparison, the similarly derived IMF for Taurus from Briceño et al. and Luhman et al. rises quickly to a peak near 0.8 M☉ and steadily declines to lower masses. The distinctive shapes of the IMFs in IC 348 and Taurus are reflected in the distributions of spectral types, which peak at M5 and K7, respectively. These data provide compelling, model-independent evidence for a significant variation of the IMF with star-forming conditions.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b77a7dadb83a1f410c54d25c75704db911fc6d17

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In Astronomy and Astrophysics

1. K. Luhman
2. L. Hillenbrand
3. Eric Mamajek
4. Michael C. Liu
5. N. Evans II
6. P. Myers
7. G. Herczeg
8. L. Hartmann

In Instrumentation

1. K. Luhman
2. Michael C. Liu
3. L. Hillenbrand
4. Eric Mamajek
5. T. Dupuy
6. A. Burgasser
7. K. Allers
8. Kelle Cruz

Citations in the corpus

• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics Observations (2007, background): “…show such variations are the Trapezium cluster (Muench et al. 2002), the Pleiades cluster (Bouvier et al. 1998), the Taurus star-forming region (Briceño et al. 2002), the embedded cluster IC 348 (Preibisch et al. 2003; Luhman et al. 2003), and the NGC 1333 molecular cloud (Wilking et al. 2004).”
• The Stellar Population of the Chamaeleon I Star-forming Region (2007, methodology): “Thus, the characteris- tic mass of the IMF exhibits no noticeable variation among Orion, Chamaeleon, and Perseus.”
• An Assessment of Dynamical Mass Constraints on Pre-Main-Sequence Evolutionary Tracks (2003, background): “…formation, with loci of pre–main-sequence binaries (e.g., Hartigan, Strom, & Strom 1994; Prato, Greene, & Simon 2003), higher order multiples (White et al. 1999), and young ‘‘star-forming’’ clusters (e.g., Luhman et al. 2003; L. A. Hillenbrand, M. R. Meyer, & J. M. Carpenter 2004, in preparation).”
• The Ages of Stars (2007, background): “The relation between spectral type and Teff is likely different for PMS stars than for dwarfs, in part due to gravity effects (Luhman et al. 2003) and also because PMS stars appear to have highly inhomogeneous atmospheres not well characterized by a single temperature.”
• The M-dwarfs in Multiples (MinMs) survey – I. Stellar multiplicity among low-mass stars within 15 pc (2015, background): “There is no evidence that the IMF varies systematically between different environments (e.g. Luhman et al. 2003; Bastian, Covey & Meyer 2010), indicating that determinations of the IMF are unable to probe the universality or diversity of star-formation.”
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus (2008, background): “The system IMF, i.e., treating binaries and multiple systems as single rather than multiple objects, peaks at M IMFTO ∼ 0.2 − 0.3 M⊙ (e.g., Chabrier 2005; Luhman et al 2003).”
• X-Shooter study of accretion in Chamaeleon I (2015, methodology): “As reported earlier on, this difference might be ascribed to the SpT-Teff relation used by HH14, which differs from that by Luhman et al. (2003), which was used here, at this late stellar type.”
• Star and Protoplanetary Disk Properties in Orion's Suburbs (2009, methodology): “…2008; Spezzi et al. 2008), σOri cluster (Béjar et al. 1999; Barrado y Navascués et al. 2003; Sacco et al. 2008; Hernández et al. 2007b), Coronet cluster (Sicilia-Aguilar et al. 2008), IC 348 (Luhman et al. 2003; Lada et al. 2006), Serpens cloud core, and NGC 1333 (Winston et al. 2007, 2009)..”
• The Formation and Early Evolution of Low-Mass Stars and Brown Dwarfs (2012, methodology): “When combined with the temperature scale from Luhman et al. (2003b) and the 1 Myr isochrone of Baraffe et al. (1998), this classification implies a mass of ∼ 0.2 M⊙, which falls between the dynamical masses of the components as it should.”
• A STELLAR CENSUS OF THE TUCANA–HOROLOGIUM MOVING GROUP (2014, methodology): “If we use the young-star temperature sequence of Luhman et al. (2003) for ≥M1, the sequence is shifted ∼0.5 subclass later for a given mass or temperature.”
• INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS (2013, background): “Since pre-MS stars have surface gravities intermediate between dwarfs and giants, we expect that a pre-MS Teff scale will be intermediate between dwarfs and giants (e.g., Luhman et al. 2003).”
• UV Excess Measures of Accretion onto Young Very Low Mass Stars and Brown Dwarfs (2008, methodology): “In the Baraffe et al. (1998) pre-main sequence evolutionary tracks at 2 Myr and with temperatures from Luhman et al. (2003), a difference of 0.5 spectral classes corresponds to 25% larger mass and a 10% smaller radius.”
• The Spectroscopically Determined Substellar Mass Function of the Orion Nebula Cluster (2004, background): “Similar arguments have been put forth by Luhman et al. (2003b) to explain low-lying stars on the HR diagram of IC 348.”
• AN INFRARED/X-RAY SURVEY FOR NEW MEMBERS OF THE TAURUS STAR-FORMING REGION (2009, methodology): “This variation in the IMF is illustrated in Figure 12, where we include mass functions for IC 348 and Chamaeleon I that were derived in the same manner as our measurement for Taurus (Luhman et al. 2003b; Luhman 2007).”
• The T Tauri Phase Down to Nearly Planetary Masses: Echelle Spectra of 82 Very Low Mass Stars and Brown Dwarfs (2005, methodology): “Luhman et al. (2003b) compare their IC 348 sample to that of the Brinceño et al. (2002) low-mass sample in Taurus and show that the Taurus sources appear slightly younger overall than the IC 348 ones: they ascribe a median age of 1 Myr to Taurus and 2 Myr to IC 348.”
• Mapping the Shores of the Brown Dwarf Desert. I. Upper Scorpius (2007, methodology): “For lower mass stars the effective temperatures were estimated by combining the temperature scales of Schmidt-Kaler (1982) with the M dwarf temperature scales from Luhman et al. (2003).”