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The Binarity at LOw Metallicity (BLOeM) campaign

A European Southern Observatory (ESO) Large Programme:

Monitoring of ~1000 massive stars in the low-metallicity conditions of the Small Magellanic Cloud

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P: Shenar; dPI: Bodensteiner

BLOeM  in a nutshell:

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  • Sample? 929 massive stars in the SMC

  • Instrument? FLAMES/Very Large Telescope

  • Total time? 116 hours

  • Baseline? 2 years

  • Number of visits? 25

  • Resolving power? ~7000

  • Spectral range? 395-456 nm

1920px-Small_Magellanic_Cloud_(Digitized_Sky_Survey_2).jpg

Objectives, at low metallicity:

Initial binary fraction

Mass ratio distribution

Period, eccentricity distributions

Initial mass function

Hunt for black holes

Identify post-interaction binaries

Benchmark abundance pattern

Screenshot 2024-11-26 at 14.31.26.png

The BLOeM sample, marked on a Gaia color-magnitude diagram of the Small Magellanic Cloud.

The sample targets massive stars (M > 8Msun) of all types, excluding red supergiants. Completeness with respect to the Gaia catalogue is shown in the left panel. Adapted from Shenar et al. 2024

Screenshot 2024-11-26 at 14.28.39.png

Hertzsprung-Russell diagram of the BLOeM sample, constructed from derived spectral types. Adapted from Shenar et al. 2024

BLOeM publications

1. Binarity at LOw Metallicity (BLOeM): A spectroscopic VLT monitoring survey of massive stars in the SMC 

   Shenar, Bodensteiner et al. 2024, A&A, 690, 289 

​   Survey description and spectral classification of the sample

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2. A high fraction of close massive binary stars at low metallicity 

   Sana, Shenar, Bodensteiner et al. 2024, submitted

​   9-epoch multiplicity analysis of the O-type stars

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3. Binarity at LOw Metallicity (BLOeM): Multiplicity properties of Oe and Be stars

   Bodensteineret al. 2024, submitted to A&A

​   9-epoch multiplicity analysis of the OBe stars

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4. Binarity at LOw Metallicity (BLOeM): The multiplicity properties of BAF-type supergiants 

   Patrick et al. 2024, submitted to A&A

​   9-epoch multiplicity analysis of the BAF supergiants

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5. Binarity at LOw Metallicity (BLOeM): multiplicity of early B-type supergiants in the SMC

   Britavskiy et al. 2024, submitted to A&A

​   9-epoch multiplicity analysis of the B-type supergiants

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6. Binarity at LOw Metallicity (BLOeM): Enhanced multiplicity in early B-type dwarfs and giants at Z=0.2 Zsun 

   Villaseñor et al. 2024, submitted to A&A

​   9-epoch multiplicity analysis of the B-type dwarfs and giants​

 

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