Massive unseen companions to hot faint underluminous stars from SDSS (MUCHFUSS) - Analysis of seven close subdwarf B binaries

Abstract

The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M > 1.0 Msun), neutron stars or stellar mass black holes. The existence of such systems is predicted by binary evolution theory and recent discoveries indicate that they exist in our Galaxy. First results are presented for seven close binary sdBs with short orbital periods ranging from 0.21 d to 1.5 d. The atmospheric parameters of all objects are compatible with core helium-burning stars. The companions are most likely white dwarfs. In one case the companion could be shown to be a white dwarf by the absence of light-curve variations. However, in most cases late type main sequence stars cannot be firmly excluded. Comparing our small sample with the known population of close sdB binaries we show that our target selection method aiming at massive companions is efficient. The minimum companion masses of all binaries in our sample are high compared to the reference sample of known sdB binaries.

14 pages, 7 figures, 7 tables, A&A accepted

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Cited by in corpus (32)

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• A progenitor binary and an ejected mass donor remnant of faint type Ia supernovae
• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• The MUCHFUSS project - Searching for hot subdwarf binaries with massive unseen companions: Survey, target selection and atmospheric parameters
• New binaries among UV-selected, hot subdwarf stars and population properties
• The catalogue of radial velocity variable hot subluminous stars from the MUCHFUSS project
• Binaries discovered by the MUCHFUSS project SDSS J08205+0008 - An eclipsing subdwarf B binary with brown dwarf companion
• Binaries discovered by the MUCHFUSS project: SDSS J162256.66$+$473051.1 - An eclipsing subdwarf B binary with a brown dwarf companion
• A Catalogue of Potential Post Common Envelope Binaries
• The Hyper-MUCHFUSS project: probing the Galactic halo with sdB stars
• A new bright eclipsing hot subdwarf binary from the ASAS and SuperWASP surveys
• A quantitative in-depth analysis of the prototype sdB+BD system SDSS J08205+0008 revisited in the Gaia era
• Radial velocity variability and evolution of hot subdwarf stars
• SHOTGLAS I: The ultimate spectroscopic census of extreme horizontal branch stars in $\omega$ Centauri
• Orbital properties of an unusually low-mass sdB star in a close binary system with a white dwarf
• Orbital solutions of eight close sdB binaries and constraints on the nature of the unseen companions
• Two candidate brown dwarf companions around core helium-burning stars
• Binaries discovered by the SPY survey VI. Discovery of a low mass companion to the hot subluminous planetary nebula central star EGB\,5 - A recently ejected common envelope?
• The MUCHFUSS photometric campaign
• Hot subdwarfs in close binaries observed from space II: Analysis of the light curves
• Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. II. Kinematics
• The Unseen Population of F to K-type Companions to Hot Subdwarf Stars
• Binaries discovered by the MUCHFUSS project; FBS 0117+396: An sdB+dM binary with a pulsating primary
• A spectroscopic and kinematic survey of fast hot subdwarfs
• Hot subdwarfs - Small stars marking important events in stellar evolution
• Hot Subdwarf Formation: Confronting Theory with Observation
• Discovery of periodic variables in the hot subdwarf catalogue through a systematic search in Zwicky Transient Facility data
• Hot subdwarf stars from the Hamburg Quasar Survey
• MUCHFUSS - Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS
• Observing Orbital Decay in the Ultracompact Hot Subdwarf Binary System ZTFJ213056.71+442046.5