2018MNRAS.476.2117R


C.D.S. - SIMBAD4 rel 1.7 - 2021.05.16CEST19:36:59

2018MNRAS.476.2117R - Mon. Not. R. Astron. Soc., 476, 2117-2136 (2018/May-2)

Detecting outliers and learning complex structures with large spectroscopic surveys - a case study with APOGEE stars.

REIS I., POZNANSKI D., BARON D., ZASOWSKI G. and SHAHAF S.

Abstract (from CDS):

In this work, we apply and expand on a recently introduced outlier detection algorithm that is based on an unsupervised random forest. We use the algorithm to calculate a similarity measure for stellar spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We show that the similarity measure traces non-trivial physical properties and contains information about complex structures in the data. We use it for visualization and clustering of the data set, and discuss its ability to find groups of highly similar objects, including spectroscopic twins. Using the similarity matrix to search the data set for objects allows us to find objects that are impossible to find using their best-fitting model parameters. This includes extreme objects for which the models fail, and rare objects that are outside the scope of the model. We use the similarity measure to detect outliers in the data set, and find a number of previously unknown Be-type stars, spectroscopic binaries, carbon rich stars, young stars, and a few that we cannot interpret. Our work further demonstrates the potential for scientific discovery when combining machine learning methods with modern survey data.

Abstract Copyright: © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): methods: data analysis - stars: general - stars: peculiar

VizieR on-line data: <Available at CDS (J/MNRAS/476/2117): apogeenn.dat distance.dat tsnecoor.dat>

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 M 32 IG 00 42 41.825 +40 51 54.61 9.51 9.03 8.08     ~ 2038 2
2 HD 22877 * 03 41 12.8804804326 +24 53 34.601612875   9.775 8.939     G0 7 0
3 UCAC3 287-65819 * 04 05 26.2373386346 +53 04 49.434522275   16.11 15.13 15.434 13.78 ~ 2 0
4 UCAC4 505-012222 * 05 26 44.7838179120 +10 49 15.321838011   17.24 15.65 15.49 13.22 ~ 3 0
5 2MASS J06305204+0515509 RG* 06 30 52.0432123353 +05 15 50.987503671   12.7       ~ 4 0
6 GSC 04799-00986 * 06 41 50.6391513811 -01 30 17.838805611   13.50 12.66 12.39   M1V 7 0
7 V* W UMa EB* 09 43 45.4704899627 +55 57 09.066718574   8.54 7.75     G2Vn 639 1
8 UCAC3 121-327581 * 17 53 45.7153739694 -29 49 36.422463854   17.92 15.27 15.424 15.00 ~ 5 0
9 EM* MWC 922 Be* 18 21 16.059408 -13 01 25.68432     13.80 13.65   B[e] 85 0
10 V* V1610 Cyg pA* 21 02 18.27 +36 41 37.0           F5Iae 840 1
11 UCAC3 352-14203 * 23 37 56.5247143656 +85 34 45.009474556   15.09 14.09 14.267 13.07 ~ 1 0

    Equat.    Gal    SGal    Ecl

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2021.05.16-19:36:59

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