Modeling Brown Dwarfs , L Dwarfs , and T Dwarfs

نویسنده

  • Adam Burrows
چکیده

In this contribution, I touch on a subset of our recent efforts in spectral and opacity modeling aimed at improving our understanding of brown dwarfs, L dwarfs, and T dwarfs. I discuss theoretical calculations of the alkali line profiles, newly generated CrH opacities, new evidence for refractory rainout in T dwarfs from optical spectral measurements, and the distinction between brown dwarfs and planets.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Finding ultracool brown dwarfs with MegaCam on CFHT: method and first results

Aims. We present the first results of a wide field survey for cool brown dwarfs with the MegaCam camera on the CFHT telescope, the Canada-France Brown Dwarf Survey, hereafter CFBDS. Our objectives are to find ultracool brown dwarfs and to constrain the field-brown dwarf mass function thanks to a larger sample of L and T dwarfs. Methods. We identify candidates in CFHT/MegaCam i and z images usin...

متن کامل

T Dwarfs and the Substellar Mass Function . I . Monte Carlo Simulations

Monte Carlo simulations of the field substellar mass function (MF) are presented, based on the latest brown dwarf evolutionary models from Burrows et al. (1997) and Baraffe et al. (2003). Starting from various representations of the MF below 0.1 M⊙ and the stellar birth rate, luminosity functions (LFs) and Teff distributions are produced for comparison with observed samples. These distributions...

متن کامل

Transition from L to T Dwarfs on the Color-Magnitude Diagram

The color-magnitude (CM) diagram of cool dwarfs and brown dwarfs based on the recent astrometry data is compared with the CM diagram transformed from the theoretical evolutionary tracks via the unified cloudy models (UCMs) of L and T dwarfs. A reasonable agreement between the models and observations is shown for the whole regime of ultracool dwarfs covering L and T dwarfs, and this is achieved,...

متن کامل

Spectroscopic rotational velocities of brown dwarfs

We have obtained projected rotation velocities (vrot sin i) of a sample of 19 ultracool dwarfs with spectral types in the interval M6.5–T8 using high-resolution, near-infrared spectra obtained with NIRSPEC and the Keck II telescope. Among our targets there are two young brown dwarfs, two likely field stars, and fifteen likely brown dwarfs (30–72MJup) of the solar neighborhood. Our results indic...

متن کامل

Infrared Parallaxes for Methane T Dwarfs

We report final results from our 2.5 year infrared parallax program carried out with the European Southern Observatory 3.5m New Technology Telescope and the SOFI infrared camera. Our program targeted precision astrometric observations of ten T type brown dwarfs in the J band. Full astrometric solutions (including trigonometric parallaxes) for nine T dwarfs are provided along with proper motion ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2002