Luminosity Functions of Young Clusters: Modeling the Substellar Mass Regime

  title={Luminosity Functions of Young Clusters: Modeling the Substellar Mass Regime},
  author={Peter Allen and David E. Trilling and David William Koerner and I. N. Reid},
  journal={The Astrophysical Journal},
We predict near-infrared luminosity functions of young (5 Myr to 1 Gyr) star clusters by combining evolutionary models of very low mass (1 MJ to 0.15 M☉) dwarfs with empirical bolometric corrections. We identify several characteristic features in our results. These can be attributed to three causes: (1) deuterium burning in the most massive substellar objects; (2) methane absorption in bodies with Teff less than 1300 K, the temperature of the L/T transition; and (3) the formation of dust clouds… 

Figures and Tables from this paper

We report our efforts to constrain the form of the low-mass star and brown dwarf mass function via Bayesian inference. Recent surveys of M, L, and T dwarfs in the local solar neighborhood are an
The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
We present new evolution sequences for very low mass stars, brown dwarfs, and giant planets and use them to explore a variety of influences on the evolution of these objects. While the predicted
Spectroscopy of Very Low Mass Stars and Brown Dwarfs in IC 2391: Lithium Depletion and Hα Emission
We have obtained intermediate-resolution optical spectroscopy of 44 candidate very low mass members of the nearby young open cluster IC 2391. Of these, 26 spectra are totally new, 14 had been
A Deep Infrared Photometric Survey for Very Low Mass Brown Dwarfs in the Pleiades
This paper presents the results of a deep infrared survey for low-mass brown dwarfs in the Pleiades cluster. By comparing J-band (1.25 μm) and I-band (0.83 μm) photometry of an ~450 arcmin2 area with
Star Formation via the Little Guy: A Bayesian Study of Ultracool Dwarf Imaging Surveys for Companions
I have undertaken a comprehensive statistical investigation of the ultracool dwarf companion distribution (spectral type M6 and later). Utilizing a Bayesian algorithm, I tested models of the
The possiblity of detection of ultracool dwarfs with the UKIRT Infrared Deep Sky Survey
We present predictions for the numbers of ultracool dwarfs in the Galactic disc population that could be detected by the WFCAM/UKIDSS Large Area Survey and Ultra Deep Survey. Simulated samples of
AB Doradus C: age, spectral type, orbit, and comparison to evolutionary models
We expand upon the results of Close et al. (2005) regarding the young, low-mass object AB Dor C and its role as a calibration point for theoretical tracks. We present an improved spectral reduction
A Neptune-sized transiting planet closely orbiting a 5–10-million-year-old star
A newly born, transiting planet orbiting its star with a period of 5.4 days is reported, which is 50 per cent larger than Neptune, and its mass is less than 3.6 times that of Jupiter, with a true mass likely to be similar to that of Neptune.
Cosmological constraints on the neutrino mass from CMB anisotropy and large-scale structure of the Universe
Using cosmological data on the CMB anisotropy and large-scale structure of the Universe, we have obtained new constraints on the sum of the masses of three generations of active neutrinos: Σmν < 1.05
New Photometry and Spectra of AB Doradus C: An Accurate Mass Determination of a Young Low-Mass Object with Theoretical Evolutionary Tracks
We present new photometric and spectroscopic measurements for the unique, young, low-mass evolutionary track calibrator AB Dor C. While the new Ks photometry is similar to that we have previously


Modeling the Near-Infrared Luminosity Functions of Young Stellar Clusters
We present the results of numerical experiments designed to evaluate the usefulness of near-infrared (NIR) luminosity functions for constraining the initial mass function (IMF) of young stellar
L Dwarfs and the Substellar Mass Function
Analysis of initial observations sky surveys has shown that the resulting photometric catalogs, combined with far-red optical data, provide an extremely effective method of finding isolated, very
Evolutionary Models for Very Low-Mass Stars and Brown Dwarfs with Dusty Atmospheres
We present evolutionary calculations for very low-mass stars and brown dwarfs based on synthetic spectra and nongray atmosphere models which include dust formation and opacity, i.e., objects with
Discovery of a cool brown dwarf
The discovery of a probable companion to the nearby star G1229, with no more than onetenth the luminosity of the least luminous hydro-gen-burning star, is reported, concluding that the companion is a brown dwarf with a temperature of less than 1,200 K, and a mass ∼20–50 times that of Jupiter.
A Survey for Low-Mass Stars and Brown Dwarfs in the Upper Scorpius OB Association
The Upper Scorpius association is the OB association nearest to the Sun (145 pc). Its young age (~5 Myr) makes it an ideal place to search for low-mass stars and brown dwarfs, as these objects should
Keck Spectra of Pleiades Brown Dwarf Candidates and a Precise Determination of the Lithium Depletion Edge in the Pleiades
We have obtained intermediate resolution spectra of 11 candidate brown dwarf members of the Pleiades open cluster using the Keck II telescope and Low-Resolution Imaging Spectrograph. Our primary goal
The Palomar/MSU Nearby Star Spectroscopic Survey. IV. The Luminosity Function in the Solar Neighborhood and M Dwarf Kinematics*
We have used new astrometric and spectroscopic observations to refine the volume-complete sample of M dwarfs defined in previous papers in this series. With the addition of Hipparcos astrometry, our
The Lithium-Depletion Boundary and the Age of the Young Open Cluster IC 2391
In previous programs, we have identified a large number of possible, very low mass members of the young open cluster IC 2391 based on their location in an I versus (R-I)c color-magnitude diagram. We
The Initial mass function and stellar birthrate in the solar neighborhood
We examine the initial mass function (IMF) and time history of the stellar birthrate in the solar neighborhood assuming a time-independent IMF. The present-day mass function is constructed from the
On the variation of the initial mass function
A universal initial mass function (IMF) is not intuitive, but so far no convincing evidence for a variable IMF exists. The detection of systematic variations of the IMF with star-forming conditions