منابع مشابه
Parallaxes of L and T dwarfs
We discuss a new program to measure the parallaxes of a number of L and T dwarfs, objects that bridge the gap between M dwarfs and planets. This pilot project tests the feasibility of using large telescopes with infrared detectors to determine parallaxes at the level of milli-arcseconds (mas). First results show that we are able to achieve the required centroiding precision and simulations indi...
متن کاملInfrared 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 کاملParallaxes of five L Dwarfs with a Robotic Telescope
We report the parallax and proper motion of five L dwarfs obtained with observations from the robotic Liverpool Telescope. Our derived proper motions are consistent with published values and have considerably smaller errors. Based on our spectral type versus absolute magnitude diagram, we do not find any evidence for binaries among our sample, or, at least no comparable mass binaries. Their spa...
متن کاملAccreting White Dwarfs
Thermonuclear (type Ia) supernovae are explosions in accreting white dwarfs, but the exact scenario leading to these explosions is still unclear. An important step to clarify this point is to understand the behaviour of accreting white dwarfs in close binary systems. The characteristics of the white dwarf (mass, chemical composition, luminosity), the accreted material (chemical composition) and...
متن کاملObservations of Ultracool White Dwarfs
We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346]246. Along with F351[50, these white dwarfs are the coolest ones known, all with e†ective temperatures below 4000 K. Their membership in the Galactic halo population is discussed, and detailed comparisons of all three objects with new atmosphere models are presented. The new models consider the e†...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1971
ISSN: 0074-1809
DOI: 10.1017/s0074180900097023