2018A&A...619A.125A


Query : 2018A&A...619A.125A

2018A&A...619A.125A - Astronomy and Astrophysics, volume 619A, 125-125 (2018/11-1)

Dissecting stellar chemical abundance space with t-SNE.

ANDERS F., CHIAPPINI C., SANTIAGO B.X., MATIJEVIC G., QUEIROZ A.B., STEINMETZ M. and GUIGLION G.

Abstract (from CDS):

In the era of large-scale Galactic astronomy and multi-object spectroscopic stellar surveys, the sample sizes and the number of available stellar chemical abundances have reached dimensions in which it has become difficult to process all the available information in an effective manner. In this paper we demonstrate the use of a dimensionality-reduction technique (t-distributed stochastic neighbour embedding; t-SNE) for analysing the stellar abundance-space distribution. While the non-parametric non-linear behaviour of this technique makes it difficult to estimate the significance of any abundance-space substructure found, we show that our results depend little on parameter choices and are robust to abundance errors. By reanalysing the high-resolution high-signal-to-noise solar-neighbourhood HARPS-GTO sample with t-SNE, we find clearer chemical separations of the high- and low-[α/Fe] disc sequences, hints for multiple populations in the high-[α/Fe] population, and indications that the chemical evolution of the high-[α/Fe] metal-rich stars is connected with the super-metal-rich stars. We also identify a number of chemically peculiar stars, among them a high-confidence s-process-enhanced abundance-ratio pair (HD 91345/HD 126681) with very similar ages and vX and vY velocities, which we suggest have a common birth origin, possibly a dwarf galaxy. Our results demonstrate the potential of abundance-space t-SNE and similar methods for chemical-tagging studies with large spectroscopic surveys.

Abstract Copyright: © ESO 2018

Journal keyword(s): solar neighborhood - Galaxy: abundances - Galaxy: disk - Galaxy: stellar content - stars: abundances

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 11397 PM* 01 51 40.5281107159 -16 19 03.566317848   9.63 9.02     G6IV/V 117 0
2 HD 14452 PM* 02 13 34.8024473112 -79 01 26.192880300   10.11 9.34     K0V 41 0
3 HD 28701 PM* 04 25 45.8486750616 -69 59 37.265127612   8.48 7.87     G2V 75 0
4 HD 29428 PM* 04 36 15.2519727336 -39 24 52.180369776   9.66 8.99     G3/5V 31 0
5 HD 91345 Pe* 10 30 04.6048336584 -71 33 39.248662428   9.757 9.510     G0wF3 70 0
6 CD-43 6810 PM* 11 08 40.0891980744 -44 15 33.814235556   10.38 9.82     F8 62 0
7 HD 113513 PM* 13 06 50.5849424232 -77 52 13.737559836   9.46 8.77     G5V 40 0
8 HD 126681 PM* 14 27 24.9094012952 -18 24 40.454425566   9.939 9.535     G3V 179 0
9 HD 126803 PM* 14 29 03.2566979746 -46 44 28.042678695   9.62 8.94     G5V 60 0
10 BD+08 3095 PM* 15 50 58.9334638272 +08 25 23.721884040   10.60   9.8   G2 79 0
11 CD-45 12460 PM* 18 25 01.8452694624 -45 28 47.386729092   11.48 10.96     F8 42 0
12 HD 175179 PM* 18 54 23.2029803432 -04 36 18.621907480 9.56 9.61 9.03     G5V 114 0
13 HD 212036 PM* 22 22 13.6338911976 -39 49 12.560278044   9.15 8.47     G5V 47 0
14 NAME Galactic Bulge reg ~ ~           ~ 3895 0

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2022.08.09-04:34:46

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