Advanced

Signatures of SN Ia in the galactic thick disk. Observational evidence from alpha -elements in 67 dwarf stars in the solar neighbourhood

Feltzing, Sofia LU ; Bensby, Thomas LU and Lundström, Ingemar LU (2003) In Astronomy & Astrophysics 397(1). p.1-4
Abstract
We present the first results of a larger study into the stellarabundances and chemical trends in long-lived dwarf stars in the solarneighbourhood that belong to (based on their kinematics) the thin andthick galactic disk, respectively. We confirm that the trends of alpha-elements in the thin and thick disk are distinct (this has previouslybeen shown for Mg by Fuhrmann cite{Fuhrmann}, but e.g. Chen et al.cite{Chen} claimed the trends to follow smoothly upon each other). Wefind that the thick disk show the typical signature of contribution fromSN Ia (i.e. the ``knee'') to the enrichment of the interstellar gas outof which the later generations of thick disk stars formed. The trendstarts out as [Mg/Fe] ~ 0.35 at [Fe/H] ~ -0.7 and continue on... (More)
We present the first results of a larger study into the stellarabundances and chemical trends in long-lived dwarf stars in the solarneighbourhood that belong to (based on their kinematics) the thin andthick galactic disk, respectively. We confirm that the trends of alpha-elements in the thin and thick disk are distinct (this has previouslybeen shown for Mg by Fuhrmann cite{Fuhrmann}, but e.g. Chen et al.cite{Chen} claimed the trends to follow smoothly upon each other). Wefind that the thick disk show the typical signature of contribution fromSN Ia (i.e. the ``knee'') to the enrichment of the interstellar gas outof which the later generations of thick disk stars formed. The trendstarts out as [Mg/Fe] ~ 0.35 at [Fe/H] ~ -0.7 and continue on this levelwith increasing [Fe/H] until -0.4 dex where a decline in [Mg/Fe] startsand steadily continues down to 0 dex at solar metallicity. The same istrue for the other alpha -elements (e.g. Si). Using ages from theliterature we find that the thick disk in the mean is older than thethin disk. Combining our results with other observational facts wesuggest that the most likely formation scenario for the thick disk is,still, a violent merger event. We also suggest that there might betentative evidence for diffusion of orbits in todays thin disk (based onkinematics in combination with elemental abundances). Based onobservations collected at the European Southern Observatory, La Silla,Chile, Proposals #65.L-0019(B) and 67.B-0108(B). (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
formation, Galaxy: disk, Galaxy: abundances, stars: abundances, stars: kinematics, Galaxy: solar neighbourhood
in
Astronomy & Astrophysics
volume
397
issue
1
pages
1 - 4
publisher
EDP Sciences
external identifiers
  • wos:000179768500001
ISSN
0004-6361
DOI
10.1051/0004-6361:20021661
language
English
LU publication?
yes
id
c3b0ebdb-1ef3-4abf-ad16-2a48b28ff2f7 (old id 130603)
alternative location
http://arxiv.org/abs/astro-ph/0211589
date added to LUP
2007-07-13 09:56:40
date last changed
2016-09-20 15:08:00
@article{c3b0ebdb-1ef3-4abf-ad16-2a48b28ff2f7,
  abstract     = {We present the first results of a larger study into the stellarabundances and chemical trends in long-lived dwarf stars in the solarneighbourhood that belong to (based on their kinematics) the thin andthick galactic disk, respectively. We confirm that the trends of alpha-elements in the thin and thick disk are distinct (this has previouslybeen shown for Mg by Fuhrmann cite{Fuhrmann}, but e.g. Chen et al.cite{Chen} claimed the trends to follow smoothly upon each other). Wefind that the thick disk show the typical signature of contribution fromSN Ia (i.e. the ``knee'') to the enrichment of the interstellar gas outof which the later generations of thick disk stars formed. The trendstarts out as [Mg/Fe] ~ 0.35 at [Fe/H] ~ -0.7 and continue on this levelwith increasing [Fe/H] until -0.4 dex where a decline in [Mg/Fe] startsand steadily continues down to 0 dex at solar metallicity. The same istrue for the other alpha -elements (e.g. Si). Using ages from theliterature we find that the thick disk in the mean is older than thethin disk. Combining our results with other observational facts wesuggest that the most likely formation scenario for the thick disk is,still, a violent merger event. We also suggest that there might betentative evidence for diffusion of orbits in todays thin disk (based onkinematics in combination with elemental abundances). Based onobservations collected at the European Southern Observatory, La Silla,Chile, Proposals #65.L-0019(B) and 67.B-0108(B).},
  author       = {Feltzing, Sofia and Bensby, Thomas and Lundström, Ingemar},
  issn         = {0004-6361},
  keyword      = {formation,Galaxy: disk,Galaxy: abundances,stars: abundances,stars: kinematics,Galaxy: solar neighbourhood},
  language     = {eng},
  number       = {1},
  pages        = {1--4},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {Signatures of SN Ia in the galactic thick disk. Observational evidence from alpha -elements in 67 dwarf stars in the solar neighbourhood},
  url          = {http://dx.doi.org/10.1051/0004-6361:20021661},
  volume       = {397},
  year         = {2003},
}