GAIA: Composition, formation and evolution of the Galaxy

Perryman, M. A. C.; Boer, K. S. de; Gilmore, G.; Høg, E.; Lattanzi, M. G.; Lindegren, L.; Luri, X.; Mignard, F.; Pace, O.; Zeeuw, P. T. de

doi:10.1051/0004-6361:20010085

Cited by 1,032 publications

(1,031 citation statements)

References 26 publications

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“…The AstraLux Large M Dwarf Survey, from which these binaries were selected for spectroscopic characterisation, discovered ≈ 200 nearby, lowmass binary systems, many of which belong to YMGs. Ongoing orbital monitoring together with precise parallactic distances obtained with Gaia (Perryman et al 2001) will within a few years provide dynamical masses for a large number of binaries, providing stringent constraints on evolutionary models for young, low-mass stars.…”

Section: Discussionmentioning

confidence: 99%

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Bergfors¹,

Brandner²,

Bonnefoy³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present VLT/SINFONI J, H + K spectra of seven close visual pairs in M dwarf binary/triple systems, discovered or observed by the AstraLux M dwarf survey. We determine the spectral types to within ±1.0 subclasses from comparison to template spectra and the strength of K-band water absorption, and derive effective temperatures. The results are compared to optical spectral types of the unresolved binary/multiple systems, and we confirm that our photometric method to derive spectral types in the AstraLux M dwarf survey is accurate. We look for signs of youth such as chromospheric activity and low surface gravity, and find an age in the range 0.25 − 1 Gyr for the GJ 852 system. Strong Li absorption is detected in optical spectra of the triple system J024902 obtained with FEROS at the ESO-MPG 2.2 m telescope. The equivalent width of the absorption suggests an age consistent with the β Pic moving group. However, further observations are needed to establish group membership. Ongoing orbital monitoring will provide dynamical masses and thus calibration of evolutionary models for low mass stars.

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Section: Discussionmentioning

confidence: 99%

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Bergfors¹,

Brandner²,

Bonnefoy³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…The Hipparcos catalogue has probably missed about one half of the encounters (Feng 2015), which have encountered (or will encounter) the solar system over the past (or future) 10 Myr. Gaia (Perryman et al 2001) should detect more than 90% encounters over the past/future 10 Myr and provide accurate astrometric and spectrophotometric measurements for them (Feng 2015). Our work shows that future studies of encounters should focus not only on close encounters but also on massive and slow encounters.…”

Section: Discussionmentioning

confidence: 80%

Finding the imprints of stellar encounters in long-period comets

Feng

Bailer‐Jones

2015

Mon. Not. R. Astron. Soc.

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The solar system's Oort cloud can be perturbed by the Galactic tide and by individual passing stars. These perturbations can inject Oort cloud objects into the inner parts of the solar system, where they may be observed as the long-period comets (periods longer than 200 years). Using dynamical simulations of the Oort cloud under the perturbing effects of the tide and 61 known stellar encounters, we investigate the link between long-period comets and encounters. We find that past encounters were responsible for injecting at least 5% of the currently known long-period comets. This is a lower limit due to the incompleteness of known encounters. Although the Galactic tide seems to play the dominant role in producing the observed long-period comets, the non-uniform longitude distribution of the cometary perihelia suggests the existence of strong -but as yet unidentified -stellar encounters or other impulses. The strongest individual future and past encounters are probably HIP 89825 (Gliese 710) and HIP 14473, which contribute at most 8% and 6% to the total flux of long-period comets, respectively. Our results show that the strength of an encounter can be approximated well by a simple proxy, which will be convenient for quickly identifying significant encounters in large data sets. Our analysis also indicates a smaller population of the Oort cloud than is usually assumed, which would bring the mass of the solar nebula into line with planet formation theories.

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“…2004), ∼80 000 in TASS (Droege et al 2006) etc. Gaia will make a revolution in these numbers since the aimed census of the overall stellar population is ∼ 1 billion up to Pipeline Reduction of Binary Light Curves 3 V = 20 (Perryman et al 2001). Admittedly, magnitude levels and variability detection threshold change from survey to survey, but a shortage of eclipsing binaries in the databases is more than obvious.…”

Section: Intention and Planningmentioning

confidence: 99%

“…To date, there are about 10 000 photometric/RV data-sets that in principle allow modeling to a 3% accuracy. By 2020, the upcoming missions such as Pan-Starrs (Kaiser et al 2002) and Gaia (Perryman et al 2001) will have pushed this number to ∼10 000 000. Even if all observational facilities collapsed at that point so that no further data got collected, it would take 12 500 astronomers to analyse these data in the next 100 years!…”

Section: Introductionmentioning

confidence: 99%

Pipeline Reduction of Binary Light Curves from Large–Scale Surveys

Prša

Zwitter

2006

Proc. IAU

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Abstract.One of the most important changes in observational astronomy of the 21 st Century is a rapid shift from classical object-by-object observations to extensive automatic surveys. As CCD detectors are getting better and their prices are getting lower, more and more small and medium-size observatories are refocusing their attention to detection of stellar variability through systematic sky-scanning missions. This trend is aditionally powered by the success of pioneering surveys such as ASAS, DENIS, OGLE, TASS, their space counterpart Hipparcos and others. Such surveys produce massive amounts of data and it is not at all clear how these data are to be reduced and analysed. This is especially striking in the eclipsing binary (EB) field, where most frequently used tools are optimized for object-by-object analysis. A clear need for thorough, reliable and fully automated approaches to modeling and analysis of EB data is thus obvious. This task is very difficult because of limited data quality, non-uniform phase coverage and solution degeneracy. This paper reviews recent advancements in putting together semi-automatic and fully automatic pipelines for EB data processing. Automatic procedures have already been used to process Hipparcos data, LMC/SMC observations, OGLE and ASAS catalogs etc. We discuss the advantages and shortcomings of these procedures.

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GAIA: Composition, formation and evolution of the Galaxy

Cited by 1,032 publications

References 26 publications

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Finding the imprints of stellar encounters in long-period comets

Pipeline Reduction of Binary Light Curves from Large–Scale Surveys

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