J/ApJS/267/5 S-type stars from LAMOST MRS DR10 spectra (Chen+, 2023)
S-type stars from LAMOST DR10: classification of intrinsic and extrinsic stars.
Chen J., Li Y.-B., Luo A.-L., Ma X.-X., Li S.
<Astrophys. J. Suppl. Ser., 267, 5 (2023)>
=2023ApJS..267....5C 2023ApJS..267....5C
ADC_Keywords: Stars, S; Spectra, optical; Surveys; Photometry, infrared;
Abundances
Keywords: S stars
Abstract:
In this paper, we found 2939 S-type stars from LAMOST Data Release 10
using two machine-learning methods, and 2306 of them were reported for
the first time. The main purpose of this work is to study how to
divide S-type stars into intrinsic and extrinsic stars with
photometric data and LAMOST spectra. Using infrared photometric data,
we adopted two methods to distinguish S-type stars, i.e., the XGBoost
algorithm and color-color diagrams. We trained the XGBoost model with
15 input features consisting of colors and absolute magnitudes from
Two Micron All Sky Survey (2MASS), AllWISE, AKARI, and IRAS, and found
that the model trained by input features with 2MASS, AKARI, and IRAS
data has the highest accuracy of 95.52%. Furthermore, using this
XGBoost model, we found four color-color diagrams with six infrared
color criteria to divide S-type stars, which have an accuracy of about
90%. Applying the two methods to the 2939 S-type stars,
381 (XGBoost)/336 (color-color diagrams) intrinsic and
495 (XGBoost)/82 (color-color diagrams) extrinsic stars were
classified, respectively. Using these photometrically classified
intrinsic and extrinsic stars, we retrained the XGBoost model with
their blue and red medium-resolution spectra, and the 2939 stars were
divided into 855 intrinsic and 2056 extrinsic stars from spectra with
an accuracy of 94.82%. In addition, we also found the four spectral
regions of ZrI (6451.6Å), NeII (6539.6Å), Hα (6564.5Å),
and FeI (6609.1Å) and CI (6611.4Å) are the most important
features, which can reach an accuracy of 92.1% when using them to
classify S-type stars.
Description:
Since 2018 October, LAMOST started the phase II survey, which contains
both low- (R∼1800) and medium- (R∼7500) resolution spectroscopic
surveys. From 2021 October to 2022 June, LAMOST DR10 collected
8,099,218 single-exposure spectra and 2,205,500 coadded spectra.
In our previous paper (Paper I; Chen+ 2022, J/ApJ/931/133), 606 S-type
stars were found from LAMOST MRS DR9.
In this work, only the machine-learning methods were used to find
S-type stars from MRS of LAMOST DR10, and the 606 S-type stars from
Paper I were treated as positive samples to search for more complete
S-type samples.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 121 2939 2939 S-type stars in this work
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/297 : AKARI/IRC mid-IR all-sky Survey (ISAS/JAXA, 2010)
II/338 : IRAS PSC/FSC Combined Catalogue (Abrahamyan+ 2015)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
V/155 : GDR2AP. Gaia DR2, 2MASS, AllWISE astrophys. param. (Fouesneau+, 2022)
J/A+A/387/129 : IR observations of S stars (Wang+, 2002)
J/ApJ/831/20 : C/O and Mg/Si for solar neighborhood's stars (Brewer+, 2016)
J/A+A/601/A10 : MARCS model atmospheres for S stars (Van Eck+, 2017)
J/ApJS/234/31 : Carbon stars from LAMOST using machine learning (Li+, 2018)
J/AJ/158/22 : IR study of intrinsic & extrinsic S-type stars (Chen+, 2019)
J/A+A/626/A127 : Barium and related stars and WD companions (Jorissen+, 2019)
J/MNRAS/490/157 : Fastest stars in the Galaxy with Gaia DR2 (Marchetti+, 2019)
J/A+A/633/A135 : Solar neighbourhood carbon stars properties (Abia+, 2020)
J/A+A/664/A45 : Characterisation of Galactic carbon stars (Abia+, 2022)
J/ApJ/931/133 : S-type stars from LAMOST MRS DR9 with Gaia DR2 (Chen+, 2022)
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- LAMOST LAMOST DR10 designation (JHHMMSS.ss+DDMMSS.s)
21- 31 F11.7 deg RAdeg Right Ascension (J2000)
33- 43 F11.8 deg DEdeg [-10/84] Declination (J2000)
45- 49 F5.2 mag Jmag [3/13.1]? 2MASS J band magnitude
51- 55 F5.2 mag Hmag [1.97/13]? 2MASS H band magnitude
57- 61 F5.2 mag Ksmag [1/13]? 2MASS Ks band magnitude
63- 68 F6.2 Jy F9um [0.04/277]? AKARI 9um flux
70- 75 F6.2 Jy F18um [0.07/204]? AKARI 18um flux
77- 82 F6.2 Jy F12um [0.08/342]? IRAS 12um flux
84- 89 F6.2 Jy F25um [0.04/195]? IRAS 25um flux
91- 103 A13 --- Type SIMBAD main object type
105- 108 F4.2 --- C/O-M [0.5/1]? Carbon to oxygen abundance ratio
estimated by the MARCS S-type star model
110- 113 F4.2 --- C/O-A [0.37/0.98]? C/O estimated by the [C/Fe] and
[O/Fe] from APOGEE DR17
115 A1 --- ClXGB [EI] Classified result from XGBoost model
(I=Intrinsic S-type; E=extrinsic S-type star)
117 A1 --- ClCol [EI] Classified result from color-color
diagram (I=Intrinsic S-type;
E=extrinsic S-type star
119 A1 --- ClSp [EI] Classified result from optical spectrum
(I=Intrinsic S-type; E=extrinsic S-type star)
121 A1 --- ERV [TF] Sources with large variations in RVs
(T=520 occurrences)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Chen et al. Paper I 2022ApJ...931..133C 2022ApJ...931..133C Cat. J/ApJ/931/133
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Aug-2023