Non-thermal radio continuum emission from young nearby stars

Abstract

Young and magnetically active low-mass stars often exhibit non-thermal coronal radio emission due to the gyration of electrons in their magnetized chromospheres. This emission is easily detectable at centimeter wavelengths with the current sensitivity of large radio interferometers like the VLA. With the aim of identifying nearby stars adequate for future accurate radio astrometric monitoring using Very Long Baseline Interferometry (VLBI), we have used the VLA in its B\, configuration to search for radio emission at \mbox{$\nu \simeq 6$\,GHz} \mbox{($\lambda \simeq 5$\,cm)} toward a sample of 170 nearby ($<$130\,pc) mostly young (5\,--\,500\,Myr) stars of spectral types between F4 and M2. At our mean $3\sigma$ detection limit of $\simeq$\,50\,$\mu$Jy, we identify 31 young stars with coronal radio emission (an 18\% system detection rate) and more than 600 background (most likely extra-galactic) sources. Among the targeted stars, we find a significant decline of the detection rate with age from 56$\pm$20\% for stars with ages $\le 10$\,Myr to 10$\pm$3\% for stars with ages 100\,--\,200\,Myr. No star older than 200\,Myr was detected. The detection rate also declines with $T_{\mathrm{eff}}$ from 36$\pm$10\% for stars with $T_{\mathrm{eff}}<4000$\,K to 13$\pm$3\% for earlier spectral types with $T_{\mathrm{eff}}>5000$\,K. The binarity fraction among the radio-bright stars is at least twice as high as among the radio-quiet stars. The radio-bright nearby young stars identified here provide an interesting sample for future astrometric studies using VLBI arrays aimed at searching for hitherto unknown tight binary components or even exoplanets.

24 pages, 15 figures plus electronic figures with 31 figures, 3 tables, accepted by ApJ

References in corpus (30)

• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Second ROSAT all-sky survey (2RXS) source catalogue
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Star formation near the Sun is driven by expansion of the Local Bubble
• Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary Systems
• Formation and Evolution of Planetary Systems (FEPS): Properties of Debris Dust around Solar-type Stars
• The nearest young moving groups
• The Gould's Belt Distances Survey (GOBELINS) I. Trigonometric parallax distances and depth of the Ophiuchus complex
• A Statistical Analysis of SEEDS and Other High-Contrast Exoplanet Surveys: Massive Planets or Low-Mass Brown Dwarfs?
• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• The Gould's Belt Distances Survey (GOBELINS) III. The distance to the Serpens/Aquila Molecular Complex
• A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups
• Bayesian Ages for Early-Type Stars from Isochrones Including Rotation, and a Possible Old Age for the Hyades
• The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass
• The VLT/NaCo Large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits: I- Sample definition and characterization
• Synchrotron emission from the T Tauri binary system V773 Tau A
• The SPHERE infrared survey for exoplanets (SHINE)- I Sample definition and target characterization
• Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
• The Gould Belt Very Large Array Survey IV: The Taurus-Auriga complex
• X-ray Super-Flares From Pre-Main Sequence Stars: Flare Energetics And Frequency
• BAFFLES: Bayesian Ages for Field Lower-Mass Stars
• ISPY -- NACO Imaging Survey for Planets around Young stars: Survey description and results from the first 2.5 years of observations
• The Gould's Belt Very Large Array Survey III. The Orion region
• Kernel phase imaging with VLT/NACO: high-contrast detection of new candidate low-mass stellar companions at the diffraction limit
• The Gould's Belt Very Large Array Survey II: The Serpens region
• Extreme radio flares and associated X-ray variability from young stellar objects in the Orion Nebula Cluster
• An astrometric planetary companion candidate to the M9 Dwarf TVLM 513-46546
• A VLBA Survey of radio stars in the Orion Nebula Cluster: I. The nonthermal radio population
• A VLBA Survey of radio stars in the Orion Nebula Cluster: II. Astrometry

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