NDLI: Carbon-enhanced metal-poor stars: the most pristine objects?

Content Provider	EDP Sciences
Author	M. Spite E. Caffau P. Bonifacio F. Spite H.-G. Ludwig B. Plez N. Christlieb
Abstract	Context. Carbon-enhanced metal-poor stars (CEMP) form a significant proportion of the metal-poor stars, their origin is not well understood, and this carbon-enhancement appears in stars that exhibit different abundance patterns.Aims. Three very metal-poor C-rich turnoff stars were selected from the SDSS survey, observed with the ESO VLT (UVES) to precisely determine the element abundances. In turnoff stars (unlike giants) the carbon abundance has not been affected by mixing with deep layers and is therefore easier to interpret.Methods. The analysis was performed with one dimensional (1D) local thermodynamical equilibrium (LTE) static model atmospheres. When available, non-LTE corrections were applied to the classical LTE abundances. The 3D effects on the CH and CN molecular bands were computed using hydrodynamical simulations of the stellar atmosphere (CO^{5^{BOLD) and are found to be very important.Results. To facilitate a comparison with previous results, only 1D abundances are used in the discussion. The abundances (or upper limits) of the elements enable us to place these stars in different CEMP classes. The carbon abundances confirm the existence of a plateau at A(C)= 8.25 for [Fe/H] ≥ −3.4. The most metal-poor stars ([Fe/H] < −3.4) have significantly lower carbon abundances, suggesting a lower plateau at A(C) ≈ 6.5. Detailed analyses of a larger sample of very low metallicity carbon-rich stars are required to confirm (or refute) this possible second plateau and specify the behavior of the CEMP stars at very low metallicity.}}
Page Count	12
File Format	HTM / HTML PDF
ISSN	00046361
Alternate Webpage(s)	https://www.aanda.org/articles/aa/abs/2013/04/aa20989-12/aa20989-12.html
e-ISSN	14320746
Journal	Astronomy & Astrophysics
Volume Number	552
DOI	10.1051/0004-6361/201220989
Language	English
Publisher	EDP Sciences
Publisher Date	2013-04-01
Access Restriction	Open
Rights Holder	© ESO, 2013
Subject Keyword	stars: abundances stars: carbon stars: AGB and post-AGB stars: Population II Galaxy: evolution stars: abundances / stars: carbon / stars: AGB and post-AGB / stars: Population II / Galaxy: evolution
Content Type	Text
Resource Type	Article
Subject	Astronomy and Astrophysics Space and Planetary Science

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

First stars X. The nature of three unevolved carbon-enhanced metal-poor stars

Light element abundances in carbon-enhanced metal-poor stars

[O/Fe] Estimates for Carbon-enhanced Metal-poor Stars from Near-infrared Spectroscopy

Sulphur abundances in metal-poor stars

The Hamburg/ESO R-process Enhanced Star survey (HERES) — VII. Thorium abundances in metal-poor stars

Metal-poor stars towards the Galactic bulge: A population potpourri

Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

Chemical abundances of the metal-poor horizontal-branch stars CS 22186-005 and CS 30344-033

Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

Carbon-enhanced metal-poor stars: the most pristine objects?

Similar Documents

First stars X. The nature of three unevolved carbon-enhanced metal-poor stars

Light element abundances in carbon-enhanced metal-poor stars

[O/Fe] Estimates for Carbon-enhanced Metal-poor Stars from Near-infrared Spectroscopy

Sulphur abundances in metal-poor stars

The Hamburg/ESO R-process Enhanced Star survey (HERES) — VII. Thorium abundances in metal-poor stars

Metal-poor stars towards the Galactic bulge: A population potpourri

Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

Chemical abundances of the metal-poor horizontal-branch stars CS 22186-005 and CS 30344-033

Modelling the nucleosynthetic properties of carbon-enhanced metal-poor RR Lyrae stars

Carbon-enhanced metal-poor stars: the most pristine objects?