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J/ApJ/844/18 RAVE J203843.2-002333 high-resolution spectroscopy (Placco+, 2017)

RAVE J203843.2-002333: the first highly R-process-enhanced star identified in the RAVE survey. Placco V.M., Holmbeck E.M., Frebel A., Beers T.C., Surman R.A., Ji A.P., Ezzeddine R., Points S.D., Kaleida C.C., Hansen T.T., Sakari C.M., Casey A.R. <Astrophys. J., 844, 18 (2017)> =2017ApJ...844...18P
ADC_Keywords: Stars, metal-deficient ; Abundances ; Equivalent widths Keywords: galaxy: halo ; stars: abundances ; stars: atmospheres ; stars: individual (RAVE J203843.2-002333) ; stars: Population II ; techniques: imaging spectroscopy Abstract: We report the discovery of RAVE J203843.2-002333, a bright (V=12.73), very metal-poor ([Fe/H]=-2.91), r-process-enhanced ([Eu/Fe]=+1.64 and [Ba/Eu]=-0.81) star selected from the RAVE survey. This star was identified as a metal-poor candidate based on its medium-resolution (R∼1600) spectrum obtained with the KPNO/Mayall Telescope, and followed up with high-resolution (R∼66000) spectroscopy with the Magellan/Clay Telescope, allowing for the determination of elemental abundances for 24 neutron-capture elements, including thorium and uranium. RAVE J2038-0023 is only the fourth metal-poor star with a clearly measured U abundance. The derived chemical abundance pattern exhibits good agreement with those of other known highly r-process- enhanced stars, and evidence suggests that it is not an actinide-boost star. Age estimates were calculated using U/X abundance ratios, yielding a mean age of 13.0±1.1Gyr. Description: Medium-resolution spectroscopic follow-up was carried out with the Mayall 4m Telescope at Kitt Peak National Observatory. The observations were obtained in semester 2014B, using the R-C spectrograph covering the wavelength range [3500,6000]Å (R∼1600). High-resolution spectroscopic data were obtained during the 2014B and 2016A semesters, using the Magellan Inamori Kyocera Echelle (MIKE) spectrograph on the Magellan/Clay Telescope at Las Campanas Observatory. For the 2014B run, the setup yielding a resolving power of R∼38000 (blue spectral range) and R∼30000 (red spectral range). For the 2016A run, the resolving power was R∼66000 (coverage [∼3500,9000]Å). Objects: ---------------------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------------------- 20 38 43.18 -00 23 32.8 RAVEJ2038 = RAVE J203843.2-002333 22 17 01.66 -16 39 27.1 CS22892-052 = BPS CS 22892-0052 15 26 01.07 -09 11 38.9 HE1523-0901 = TYC 5594-576-1 ---------------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 39 344 Equivalent-width measurements for RAVE J2038-0023 table4.dat 34 115 Individual abundance measurements of neutron-capture elements for RAVE J2038-0023 table5.dat 45 42 Final abundance estimates for RAVE J2038-0023 figure1.dat 28 13364 Selected regions of the spectrum of RAVE J2038-0023, compared with the r-II stars HE 1523-0901 and CS 22892-052
See also: III/279 : RAVE 5th data release (Kunder+, 2017) J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985) J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992) J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004) J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005) J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008) J/AN/331/474 : Abundances of metal-poor stars (Frebel, 2010) J/A+A/516/A46 : HE 2327-5642 abundance analysis (Mashonkina+, 2010) J/ApJ/711/573 : Detailed abundances in a halo stellar stream (Roederer+, 2010) J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011) J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013) J/ApJ/794/58 : Metal-poor stars in the thick disk of the MW (Beers+, 2014) J/ApJ/781/40 : Metal-poor stars from HES survey. II. (Placco+, 2014) J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014) J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014) J/ApJ/812/109 : HST & Keck spectroscopy of bright CEMP-s stars (Placco+, 2015) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Ion Ion or molecule identifier 7- 14 F8.3 0.1nm lambda [3500.8/6979] Wavelength in Angstroms 16- 19 F4.2 eV chi [0.0/4.5] Excitation potential 21- 26 F6.3 [-] log(gf) [-5.7/0.7] Log oscillator strength 28- 33 F6.2 0.1nm EW [3/209] Equivalent Width in Angstroms 35- 39 F5.3 [Sun] logeps(x) [0/5.3] Log number abundance of Ion
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Ion Ion or molecule identifier 7- 14 F8.3 0.1nm lambda [3472.4/6645.1] Wavelength in Angstroms 16- 20 F5.3 eV chi [0/3] Excitation potential 22- 27 F6.3 [-] log(gf) [-1.6/1.5] Log oscillator strength 29- 34 F6.3 [Sun] logeps(x) [-2.2/0.6] Log number abundance of Ion
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Ion Ion or molecule identifier 8- 12 F5.2 [Sun] logepsSun [-0.6/8.5] Log number abundance of Ion (logε(X)) 14- 18 F5.2 [Sun] logeps(x) [-2.2/5.8] Log number abundance of Ion (logε(X)) 20- 24 F5.2 [Sun] [X/H] [-3.5/-1.2] Average abundance 26- 30 F5.2 [Sun] [X/Fe] Elemental abundance ratio 31 A1 --- f_[X/Fe] Flag on [C/Fe] (1) 33- 36 F4.2 [Sun] sigma [0.01/0.2] Standard deviation 38- 41 F4.2 [Sun] overSig [0.1/0.2] Standard error of the mean (2) 43- 45 I3 --- N [1/202] Number of line used
Note (1): a: [C/Fe] = +0.23 using corrections of Placco+ (2014, J/ApJ/797/21). Note (2): For elements where overlineσ is lower than 0.10, we adopt a fixed value of 0.10 (see the discussion in Section 4.6 of Placco+ 2013ApJ...770..104P).
Byte-by-byte Description of file: figure1.dat
Bytes Format Units Label Explanations
1- 11 A11 --- ID Stellar identifier (CS22892-052, HE1523-0901 or "RAVEJ2038") 13 A1 --- Panel [A-E] Figure 1 panel spectrum shown in 15- 22 F8.3 0.1nm lambda [4065/5190] Wavelength in Angstroms 24- 28 F5.3 --- NFlux [0.1/1.4] Normalized flux
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Mar-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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