Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 0803.2650

New observations of cool carbon stars in the halo

Nicolas Mauron
View original source ↗Read source document ↗Export metadata ↓

Abstract

We report new results of our search for rare, cool carbon stars located at large distances from the galactic plane. Eighteen new C stars were discovered. Six are remarkable by showing the two peculiarities of a strong infrared excess at 12 microns and a large height above the Galactic plane, from 1.7 to 6 kpc. The number of C stars with these properties has been increased to 16. Mass-loss rates were tentatively estimated by assuming that all these 16 stars are Miras and by using the correlation between Mdot and the K-12 colour index. It is found that several stars have large mass loss, with median Mdot around 4E-06 solar mass per year. It would be desirable to detect their CO emission ... Eight stars might be at more than 30 kpc from the Sun, and two at the unprecedented distance of 150 kpc (this abstract has been abridged).

Explore related subjects

astro-ph

Keep this discovery

BibTeXRIS

Nicolas Mauron. 2008-03-18. New observations of cool carbon stars in the halo. https://doi.org/10.1051/0004-6361:200809378

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2008

Origin of Europa and the Galilean Satellites

Europa is believed to have formed near the very end of Jupiter's own accretion, within a circumplanetary disk of gas and solid particles. We review the formation of the Galilean satellites in the context of current constraints and understanding of giant planet formation, focusing on recent models of satellite growth within a circumjovian accretion disk produced during the final stages of gas inflow to Jupiter. In such a disk, the Galilean satellites would have accreted slowly, in more than 10^5 yr, and in a low pressure, low gas density environment. Gravitational interactions between the satellites and the gas disk lead to inward orbital migration and loss of satellites to Jupiter. Such effects tend to select for a maximum satellite mass and a common total satellite system mass compared to the planet's mass. One implication is that multiple satellite systems may have formed and been lost during the final stages of Jupiter's growth, with the Galilean satellites being the last generation that survived as gas inflow to Jupiter ended. We conclude by discussing open issues and implications for Europa's conditions of formation.

astro-ph↗
arXiv2008

Necessity of Dark Matter in Modified Newtonian Dynamics within Galactic Scales? - Testing the Covariant MOND in Elliptical Lenses

Modified Newtonian Dynamics (MOND) and its relativistic version - TeVeS offer us an alternative perspective to understand the universe without the demand of the elusive cold dark matter. This MONDian paradigm is not only competitive with the conventional CDM in a large range of scales, but also even more successful in the galactic scale. Recently, by studying 6 lensing systems, Ferreras et al. (2008) claimed that MOND still needs dark matter even in galactic scales. When we study the same systems, however, we yield an opposite conclusion. In this contribution, we report our result and conclude that MOND does not need dark matter in galactic lensing systems. Furthermore, we extend our study to 22 SLACS (Sloan Lens ACS Survey) lenses, and obtain the same conclusion as well, i.e., no dark matter is needed in elliptical galaxies.

astro-ph↗
arXiv2008

Bulk viscosity of strange matter and r-modes in neutron stars

We discuss bulk viscosity due to non-leptonic processes involving hyperons and Bose-Einstein condensate of negatively charged kaons in neutron stars. It is noted that the hyperon bulk viscosity coefficient is a few order of magnitude larger than that of the case with the condensate. Further it is found that the hyperon bulk viscosity is suppressed in a superconducting phase. The hyperon bulk viscosity efficiently damps the r-mode instability in neutron stars irrespective of whether a superconducting phase is present or not in neutron star interior.

astro-ph↗