LAMOST J045019.27+394758.7, with peculiar abundances of N, Na, V, Zn, is possibly a Sculptor dwarf galaxy escapee

Abstract

We present the results of the high-resolution (R$\sim$60,000) spectroscopic analysis of the star LAMOSTJ045019.27+394758.7 (hereafter J045) from the list of carbon stars of LAMOST DR2. From our analysis, we find that J045 does not exhibit the spectral characteristics of carbon stars. It is found to be a metal-poor ( [Fe/H] = $-$1.05) giant that shows very unusual elemental abundances, particularly for N, Na, V, and Zn. J045 shows $\alpha$-elements (Mg, Si, Ca) with near-solar values ($<$[$\alpha$/Fe]$>$ = 0.09) in contrast to Galactic stars that show [$\alpha$/Fe] in the range 0.2 to 0.3 dex. In J045, Sc and Ti are under abundant with [X/Fe] $\le$ $-$0.25. Vanadium gives [V/Fe] = 0.51 and zinc is under-abundant with [Zn/Fe] = $-$0.62. The object exhibits near-solar abundances for Sr, Y, Ba, Pr, and Sm. The La is marginally enhanced, and Ce and Nd are marginally under-abundant in J045. With [Ba/Eu] = $-$0.38, the object falls into the category of neutron-capture rich r-I stars. The estimated abundances of various elements show that the observed abundance pattern is not compatible with the abundances characteristic of Galactic metal-poor stars but matches quite closely with the abundance pattern of Sculptor Dwarf galaxy stars of similar metallicity. Based on the above observational evidences, we suggest that the object is a possible Sculptor Dwarf Galaxy escapee.

arXiv commentAccepted for publication in MNRAS

References in corpus (49)

• The chemical composition of the Sun
• The Gaia mission
• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• The 'Forbidden' Abundance of Oxygen in the Sun
• Elemental Abundance Survey of The Galactic Thick Disk
• The First Data Release (DR1) of the LAMOST general survey
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• Great Circle tidal streams: evidence for a nearly spherical massive dark halo around the Milky Way
• First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
• Gaia Data Release 2: Mapping the Milky Way disc kinematics
• Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium
• Automatic Determination of Stellar Atmospheric Parameters and Construction of Stellar Spectral Templates of the Guoshoujing Telescope (LAMOST)
• Oxygen trends in the Galactic thin and thick disks
• Abundance Estimates for 16 Elements in 6 Million Stars from LAMOST DR5 Low-Resolution Spectra
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• Spectroscopic Studies of Very Metal-Poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements
• On the correlation of elemental abundances with kinematics among galactic disk stars
• Chemical abundances of the Milky Way thick disk and stellar halo II.: sodium, iron-peak and neutron-capture elements
• First stars IX -Mixing in extremely metal-poor giants. Variation of the 12C/13C, [Na/Mg] and [Al/Mg] ratios
• Building the Galactic halo from globular clusters: evidence from chemically unusual red giants
• Multi-Element Abundance Measurements from Medium-Resolution Spectra. I. The Sculptor Dwarf Spheroidal Galaxy
• The stellar content of the Hamburg/ESO survey. II. A large, homogeneously-selected sample of high latitude carbon stars
• Stellar Archaeology: a Keck Pilot Program on Extremely Metal- Poor Stars From the Hamburg/ESO Survey. III. The Lead (Pb) Star HE 0024-2523
• Non-LTE Line-Formation and Abundances of Sulfur and Zinc in F, G, and K Stars
• VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy
• Chemical Abundances of the Milky Way Thick Disk and Stellar Halo I.: Implications of [alpha/Fe] for Star Formation Histories in Their Progenitors
• NLTE analysis of Sr lines in spectra of late-type stars with new R-matrix atomic data
• Exploring the Origin of Lithium, Carbon, Strontium and Barium with four new Ultra Metal-Poor Stars
• linemake: An Atomic and Molecular Line List Generator
• A new abundance scale for the globular cluster 47 Tuc
• A high-resolution spectral analysis of three carbon-enhanced metal-poor stars
• Abundances of carbon-enhanced metal-poor stars as constraints on their formation
• CH stars at High Galactic Latitudes
• Zinc in the Sculptor dwarf spheroidal galaxy
• The [Zn/Fe] -- [Fe/H] trend for disk and halo stars
• More nitrogen rich B-type stars in the SMC cluster, NGC 330
• Enrichment of Zinc in galactic chemodynamical evolution models
• Carbon stars from LAMOST DR2 data
• Spectroscopic study of CEMP-(s & r/s) stars- Revisiting classification criteria and formation scenarios, highlighting i-process nucleosynthesis
• The CH fraction of Carbon stars at high Galactic latitudes
• Chemical analysis of CH stars - III: Atmospheric parameters and elemental abundances
• Subaru/HDS study of CH stars: elemental abundances for stellar neutron-capture process studies
• Discovery of a nitrogen-enhanced mildly metal-poor binary system: Possible evidence for pollution from an extinct AGB Star
• Chemical abundance analysis of 19 barium stars
• Chemical analysis of two extremely metal-poor stars HE 2148-2039 and HE 2155-2043
• HCT/HESP study of two carbon stars from the LAMOST survey
• Carbon Isotope Ratios in M10 Giants

Cited by in corpus (1)

• Chemodynamical study of two CEMP-no stars from the Hamburg/ESO Survey