Oxygen trends in the Galactic thin and thick disks

By T. Bensby, S. Feltzing, I. Lundström. 2003

178 citations recorded by the source corpus.

We present oxygen abundances for 72 F and G dwarf stars in the solar neighbourhood. Using the kinematics of the stars we divide them into two sub-samples with space velocities that are typical for the thick and thin disks, respectively. The metallicities of the stars range from (Fe/H) 0: 9t o+0:4 and we use the derived oxygen abundances of the stars to: (1) perform ad ierential study of the oxygen trends in the thin and the thick disk; (2) to follow the trend of oxygen in the thin disk to the highest metallicities. We analyze the forbidden oxygen lines at 6300 A and 6363 A as well as the (NLTE aicted) triplet lines around 7774 A. For the forbidden line at 6300 A we have spectra of very high S=N (>400) and resolution (R& 215 000). This has enabled a very accurate modeling of the oxygen line and the blending Ni lines. The high internal accuracy in our determination of the oxygen abundances from this line is reflected in the very tight trends we find for oxygen relative to iron. From these abundances we are able to draw the following major conclusions: (i) That the (O/Fe) trend at super-solar (Fe/H) continues downward which is in concordance with models of Galactic chemical evolution. This is not seen in previous studies as it has not been possible to take the blending Ni lines in the forbidden oxygen line at 6300 A properly into account; (ii) That the oxygen trends in the thin and the thick disks are distinctly dierent. This confirms and extends previous studies of the other -elements; (iii) That oxygen does not follow Mg at super-solar metallicities; (iv) We also provide an empirical NLTE correction for the infrared Oi triplet that could be used for dwarf star spectra with a S=N such that only the triplet lines can be analyzed well, e.g. stars at large distances; (v) Finally, we find that Gratton et al. (1999) overestimate the NLTE corrections for the permitted oxygen triplet lines at7774 A for the parameter space that our stars span.

Subfields: Astronomy and Astrophysics, Education, Instrumentation

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Citations in the corpus

Galactic Chemical Evolution: Carbon through Zinc (2006, methodology): “Recently, however, Bensby et al. (2004) showed 0.1 dex larger [O/Mg] for [Mg/H] < ∼ 0 and decreas- ing trend for high metallicity.”
Gaia FGK benchmark stars: Metallicity (2013, background): “…which have different spatial velocities (e.g. Soubiran 1993; Article number, page 1 of 27 Soubiran et al. 2003), different chemical abundance patterns (Bensby et al. 2004; Ramírez et al. 2007) and ages (for example the works of Fuhrmann 1998; Allende Prieto et al. 2006), than the thin disk stars.”
Oxygen abundances in nearby stars - Clues to the formation and evolution of the Galactic disk (2007, background): “Given that others have proposed that metal-rich thick-disk stars exist and define a knee (in particular Bensby et al. 2004), our solid conclusion from this is that not all metal-rich stars with thick disk kinematics show that behavior.”
The metallicity distribution of bulge clump giants in Baade’s window (2011, background): “7, which shows the new [Mg/Fe] in the bulge stars and the [Mg/Fe] found in the thin and thick discs stars by Bensby et al. (2004, 2005) and Reddy et al. (2006).”
Elemental abundance survey of the Galactic thick disc (2005, methodology): “Bensby et al. would likely contend that the principal evidence for the knee lies in their results for oxygen (Bensby et al. 2004, 2005) which show a near-linear and continuous relation for [O/Fe] versus [Fe/H] in thick-disc stars with no hint of a discontinuity at [Fe/H] ∼ −0.3.”
Oxygen, Sodium, Magnesium and Aluminium as tracers of the Galactic Bulge Formation (2006, methodology): “6 and 7 together with our results for bulge stars are abundances of the galactic thin and thick disks from the studies of Reddy et al.(2006) and Bensby et al. (2004, 2005).”
A FIRST CONSTRAINT ON THE THICK DISK SCALE LENGTH: DIFFERENTIAL RADIAL ABUNDANCES IN K GIANTS AT GALACTOCENTRIC RADII 4, 8, AND 12 kpc (2011, background): “…(e.g., Gilmore et al. 1995; Wyse & Gilmore 1995); the thick disk is older than the thin disk (e.g., Fuhrmann 2008; Bensby et al. 2007); and the thick disk is α-enhanced, at a given metallicity, with respect to the thin disk (e.g., Fuhrmann 2008; Bensby et al. 2003, 2004, 2005; Reddy et al. 2006).”
Structural Parameters of Thin and Thick Disks in Edge-on Disk Galaxies (2005, background): “Abundance Patterns and the Timing of Thick and Thin Disk Formation Studies of -element abundances of the MW have suggested that star formation in the thick disk took place over several gigayears (e.g., Bensby et al. 2004b).”
OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO (2013, background): “In order to compare our results with other works, in certain parts of this paper we will adopt, in addition to the former conditions, a “strong” kinematic criterion of P1/P2 > 10 for the thin disk and P2/P1 > 10 for the thick disk (cf. Bensby et al. 2004, 2005).”
The age–metallicity structure of the Milky Way disc using APOGEE (2017, background): “This work strongly constrains the structure of both the low and high [α/Fe] components in the Galactic disk, which are commonly considered to be interchangeable with the thin and thick components (as asserted by, e.g. Bensby et al. 2004; Adibekyan et al. 2012; Fuhrmann 1998).”
alpha-, r-, and s-process element trends in the Galactic thin and thick disks (2004, methodology): “7 and combined with the results from Bensby et al. (2003, 2004a) for an extended discussion.”
STELLAR ABUNDANCES IN THE SOLAR NEIGHBORHOOD: THE HYPATIA CATALOG (2014, result): “Their Figure 21 confirms these variations with respect to other catalogs, namely Bensby et al. (2003, 2004); Mishenina et al. (2004, 2008); Reddy et al. (2003, 2006).”
Exploring the Milky Way stellar disk - A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood (2013, methodology): “The latter feature turns out to be an important feature when determining oxygen abundances from the forbidden [Oi] line at 6300̇Å which is blended with Ni lines (see Bensby et al. 2004b).”
CHEMODYNAMICAL SIMULATIONS OF THE MILKY WAY GALAXY (2008, result): “(b) In the solar neighborhood, we can reproduce the observational trend (Edvardsson et al. 1993, open circles; Bensby et al. 2004, small filled circles; Gratton et al. 2003, triangles; Cayrel et al. 2004, large filled circles).”
Chemical Similarities Between Galactic Bulge And Local Thick Disk Red Giant Stars (2008, methodology): “We also seem to detect a similar knee in [O/Fe] for the local thick disk as advocated by Bensby et al. (2004), although this is based on only a handful of stars.”
Chemical similarities between Galactic bulge and local thick disk red giants: O, Na, Mg, Al, Si, Ca, and Ti (2010, background): “On the other hand, Bensby et al. (2003, 2004) adopted spectroscopic temperatures, therefore not only their Teff but also their [X/Fe] abundance ratios are likely more accurate for comparison of these reddened bulge regions.”