scholarly journals A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties

2021 ◽  
Author(s):  
Kareem El-Badry ◽  
Hans-Walter Rix ◽  
Tyler M Heintz
Keyword(s):  
White Dwarf ◽  
Binary Stars ◽  
Main Sequence ◽  
Sample Selection ◽  
Mass Relation ◽  
The Sun ◽  
The Public ◽  
Spatially Resolved ◽  
The Masses

Abstract We construct from Gaia eDR3 an extensive catalog of spatially resolved binary stars within ≈ 1 kpc of the Sun, with projected separations ranging from a few au to 1 pc. We estimate the probability that each pair is a chance alignment empirically, using the Gaia catalog itself to calculate the rate of chance alignments as a function of observables. The catalog contains 1.3 (1.1) million binaries with >90% (>99%) probability of being bound, including 16,000 white dwarf – main sequence (WD+MS) binaries and 1,400 WD+WD binaries. We make the full catalog publicly available, as well as the queries and code to produce it. We then use this sample to calibrate the published Gaia DR3 parallax uncertainties, making use of the binary components’ near-identical parallaxes. We show that these uncertainties are generally reliable for faint stars (G ≳ 18), but are underestimated significantly for brighter stars. The underestimates are generally $\le 30\%$ for isolated sources with well-behaved astrometry, but are larger (up to ∼80%) for apparently well-behaved sources with a companion within ≲ 4 arcsec, and much larger for sources with poor astrometric fits. We provide an empirical fitting function to inflate published σϖ values for isolated sources. The public catalog offers wide ranging follow-up opportunities: from calibrating spectroscopic surveys, to precisely constraining ages of field stars, to the masses and the initial-final mass relation of white dwarfs, to dynamically probing the Galactic tidal field.

scholarly journals Masses of the components of SB2 binaries observed with Gaia – V. Accurate SB2 orbits for 10 binaries and masses of the components of 5 binaries

2020 ◽  
Vol 496 (2) ◽  
pp. 1355-1368
Author(s):  
J-L Halbwachs ◽  
F Kiefer ◽  
Y Lebreton ◽  
H M J Boffin ◽  
F Arenou ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Main Sequence ◽  
Spectroscopic Binaries ◽  
Orbital Elements ◽  
Evolved Stars ◽  
The Individual ◽  
The Masses ◽  
Stellar Masses ◽  
Selection Of

ABSTRACT Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated.

Absolute parameters of three southern eclipsing binaries: DQ Car, BK Ind, and V4396 Sgr

2020 ◽  
Vol 493 (2) ◽  
pp. 2659-2675
Author(s):  
Derya Sürgit ◽  
Ahmet Erdem ◽  
Chris A Engelbrecht ◽  
Fred Marang
Keyword(s):  
South African ◽  
Binary Stars ◽  
Main Sequence ◽  
Interstellar Extinction ◽  
Eclipsing Binaries ◽  
Evolutionary Status ◽  
Distance Modulus ◽  
Main Sequence Stars ◽  
The Masses ◽  
Absolute Parameters

ABSTRACT We present combined photometric and spectroscopic analyses of the three southern eclipsing binary stars: DQ Car, BK Ind, and V4396 Sgr. Radial velocity curves of these three systems were obtained at the South African Astronomical Observatory, and their light curves from the available data bases and surveys were used for the analysis. 75 new times of minima for these three eclipsing binaries were derived, and their ephemerides were updated. Only the O–C diagram of DQ Car indicates a cyclical variation, which was interpreted in terms of the light-time effect due to a third body in the system. Our final models describe these three systems as Algol-like binary stars with detached configurations. The masses and radii were found to be M1 = 1.86(±0.17) M⊙, R1 = 1.63(±0.06) R⊙ and M2 = 1.74(±0.17) M⊙, R2 = 1.52(±0.07) R⊙ for the primary and secondary components of DQ Car; M1 = 1.16(±0.05) M⊙, R1 = 1.33(±0.03) R⊙ and M2 = 0.98(±0.04) M⊙, R2 = 1.00(±0.03) R⊙ for BK Ind; and M1 = 3.14(±0.22) M⊙, R1 = 3.00(±0.09) R⊙ and M2 = 3.13(±0.24) M⊙, R2 = 2.40(±0.08) R⊙ for V4396 Sgr, respectively. The distances to DQ Car, BK Ind, and V4396 Sgr were derived to be 701(±50), 285(±20), and 414(±30) pc from the distance modulus formula, taking into account interstellar extinction. The evolutionary status of these three systems was also studied. It has been found that the components of DQ Car are very young stars at the age of ∼25 Myr and those of BK Ind and V4396 Sgr are evolved main-sequence stars at the ages of ∼2.69 Gyr and ∼204 Myr, respectively.

scholarly journals Fragile Binaries: Observational Leverage on Difficult Astrophysical Problems

2006 ◽  
Vol 2 (S240) ◽  
pp. 300-305
Author(s):  
T.D. Oswalt ◽  
K.B. Johnston ◽  
M. Rudkin ◽  
T. Vaccaro ◽  
D. Valls-Gabaud
Keyword(s):  
Binary Stars ◽  
White Dwarfs ◽  
Main Sequence ◽  
Age Determination ◽  
Open Clusters ◽  
Mass Relation ◽  
Space Motion ◽  
Sequence Components ◽  
Determination Methods ◽  
Cool White Dwarfs

AbstractLoosely bound,fragilebinary stars, whose separations may reach ∼ 0.1 pc, are like open clusters with two coeval components. They provide a largely overlooked avenue for the investigation of many astrophysical questions. For example, the orbital distribution of fragile binaries with two long-lived main-sequence components provides a sensitive test of the cumulative effects of the Galactic environment. In pairs where one component is evolved, the orbits have been amplified by post-main-sequence mass loss, potentially providing useful constraints on the initial-to-final mass relation for white dwarfs. The nearly featureless spectra of cool white dwarfs usually provide little information about intrinsic radial velocity, full space motion, population membership, metallicity, etc. However, distant main sequence companions provide benchmarks against which those properties can be determined. In addition, the cooling ages of white dwarf components provide useful limits on the ages of their main sequence companions, independent of other stellar age determination methods. This paper summarizes some of the ways fragile binaries provide useful leverage on these and other problems of interest.

scholarly journals Discovery of superflares

2015 ◽  
Vol 11 (S320) ◽  
pp. 119-127
Author(s):  
Daisaku Nogami
Keyword(s):  
Total Energy ◽  
Main Sequence ◽  
High Dispersion ◽  
The Sun ◽  
Main Sequence Stars ◽  
Spacecraft Data

AbstractWe have discovered 1547 ‘superflares’ on about 279 G-type main-sequence stars by using the Kepler-spacecraft data of Q0-Q6. ‘Superflares’ mean flares that radiate total energy 10 times or more larger than that of the largest flare in the Sun ever recorded. We here briefly review our current understandings on superflares and superflare stars obtained by analyzing the Kepler data and follow-up high dispersion spectra.

scholarly journals Activity Tracers

1993 ◽  
Vol 137 ◽  
pp. 605-619
Author(s):  
Klaus G. Strassmeier
Keyword(s):  
Solar Activity ◽  
Magnetic Fields ◽  
Binary Stars ◽  
Main Sequence ◽  
Stellar Atmospheres ◽  
Late Type ◽  
Stellar Rotation ◽  
Strong Magnetic Fields ◽  
Rapid Rotation ◽  
Spatially Resolved

AbstractThe vast variety of solar-like phenomena on other late-type stars, so-called activity tracers, provide an important tool for studying the structure of active stellar atmospheres and their connection to the stellar interior via strong magnetic fields. These “chromospherically active” stars include single and binary stars as well as pre- and post-main sequence objects and have rapid rotation and deep convective layers in common. They serve as astrophysical laboratories to study the vast phenomenology of activity tracers: starspots, plages, flares, prominences, which might be seen as enhanced analogs of solar activity and could be spatially resolved due to rotationally modulated indicators. In this paper we review the current observational material and discuss its impact on our knowledge of “active” atmospheres, especially in the context of stellar rotation.

scholarly journals Significant uncertainties from calibrating overshooting with eclipsing binary systems

2018 ◽  
Vol 618 ◽  
pp. A177 ◽  
Author(s):  
Thomas Constantino ◽  
Isabelle Baraffe
Keyword(s):  
Stellar Evolution ◽  
Binary Stars ◽  
Binary Systems ◽  
Precise Measurement ◽  
Main Sequence ◽  
Stellar Mass ◽  
Main Sequence Stars ◽  
Eclipsing Binary ◽  
The Masses ◽  
Convective Boundaries

The precise measurement of the masses and radii of stars in eclipsing binary systems provides a window into uncertain processes in stellar evolution, especially mixing at convective boundaries. Recently, these data have been used to calibrate models of convective overshooting in the cores of main sequence stars. In this study we have used a small representative sample of eclipsing binary stars with 1.25 ≤ M/M⊙ < 4.2 to test how precisely this method can constrain the overshooting and whether the data support a universal stellar mass–overshooting relation. We do not recover the previously reported stellar mass dependence for the extent of overshooting and in each case we find there is a substantial amount of uncertainty, that is, the same binary pair can be matched by models with different amounts of overshooting. Models with a moderate overshooting parameter 0.013 ≤ fos ≤ 0.014 (using the scheme from Herwig et al. 1997, A&A, 324, L81) are consistent with all eight systems studied. Generally, a much larger range of f is suitable for individual systems. In the case of main sequence and early post-main sequence stars, large changes in the amount of overshooting have little effect on the radius and effective temperature, and therefore the method is of extremely limited utility.

scholarly journals Towards a precise white dwarf cooling age of a globular cluster

2008 ◽  
Vol 4 (S258) ◽  
pp. 315-316
Author(s):  
Harvey B. Richer ◽  
Saul Davis ◽  
Jason Kalirai ◽  
Aaron Dotter ◽  
R. Michael Rich
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Main Sequence ◽  
Velocity Dispersion ◽  
Theoretical Models ◽  
Age Dating ◽  
Main Sequence Stars ◽  
Final Mass ◽  
Geometric Technique ◽  
The Masses

AbstractThe white dwarf cooling age of a globular star cluster provides a potentially precise method of determining the ages of these ancient systems. This age-dating technique should be viewed as one distinct from that of turn-off ages, with a largely different set of input physics and problems. As such the ages produced by these two methods are complimentary and we seek convergent to the same value. In addition to deep photometry and astrometry of cluster stars, precise distances to the clusters and their reddenings are required. Theoretical models of both main sequence stars and cooling white dwarfs are also needed as well as the masses of the white dwarfs and an initial-final mass relationship. In this contribution I discuss a potentially precise approach to cluster distances via a geometric technique (comparing the internal proper motion dispersion of cluster stars with their radial velocity dispersion) and spectroscopically determined masses of M4 white dwarfs at the top of the cooling sequence. These latter data extend the initial-final mass relationship down to the lowest mass stars that are currently forming white dwarfs.

scholarly journals Conference summary

2008 ◽  
Vol 4 (S252) ◽  
pp. 467-473 ◽  
Author(s):  
Norbert Langer
Keyword(s):  
Mass Transfer ◽  
Binary Stars ◽  
Main Sequence ◽  
Learning Experience ◽  
The Sun ◽  
Conference Summary ◽  
Impossible Task ◽  
Physics Course

To summarize 54 mostly excellent and innovative talks, plus 57 interesting posters, is an impossible task, which I will not even try. This the more as the focus of this meeting was extraordinarily broad. We discussed many different processes in stars, from mixing to pulsations and mass transfer. And we discussed the whole spectrum of stellar types, up an down the main sequence, including the Sun, and into many branches of evolved states of single and binary stars. As we are all working on more or less particular niches in the field of stellar physics, this meant an extraordinary learning experience for most of us. Indeed, this conference offered a stellar physics course at the highest level, which can not be obtained in any other way.

scholarly journals Evolutionary Trends in Wide Binary Systems

1982 ◽  
Vol 69 ◽  
pp. 81-103
Author(s):  
Peter van de Kamp
Keyword(s):  
Stellar Evolution ◽  
White Dwarf ◽  
Binary Stars ◽  
Binary Systems ◽  
Main Sequence ◽  
Evolutionary Trends ◽  
Wide Binary ◽  
The Past ◽  
Past Half Century ◽  
Past Half

Zdenek Kopal has kindly invited me, and I have accepted, to “instruct the theoreticians on known facts”. He also asked me to express my opinion on the relative evolutionary stages of components.I am essentially an observing astronomer, occupied with stars in our immediate neighborhood, say within 10 or at most some 25 parsec, i.e., the lower main sequence and the white dwarf degenerate branch.I hope that I may perhaps contribute by surveying and reporting some relevant data. I shall touch on a number of topics, limited because of selection and lack of knowledge. My contributions to binary stars lie in the realm of parallaxes, mass-ratios and masses, – and for the past half century, perturbations, interpreted as unseen companions, stellar and otherwise. I shall briefly report on some results, and I shall be wondering and hoping that some trace of stellar evolution may possibly be present in these results. After having witnessed for more than half a century my own astronomical evolution, the time has come for me to become more aware of theoretical, evolutionary and cosmological aspects of the cosmic material, I have been playing with so long.

scholarly journals Symbiotic Binary Stars

1992 ◽  
Vol 151 ◽  
pp. 137-146
Author(s):  
Scott J. Kenyon
Keyword(s):  
White Dwarf ◽  
Binary Stars ◽  
Main Sequence ◽  
Cataclysmic Variables ◽  
Symbiotic Stars ◽  
Paper Briefly ◽  
Primary Star ◽  
Classical Novae ◽  
Long Period ◽  
Red Giant

This paper briefly reviews the physical properties of symbiotic stars: long-period interacting binaries composed of a red giant primary star and a hot companion. Two types of binaries produce symbiotic optical spectra: semi-detached systems with a main sequence secondary and detached systems with a white dwarf secondary. Semi-detached symbiotics resemble cataclysmic variables and Algol binaries, but on a much larger scale, and undergo dwarf nova-like eruptions. Wind accretion powers detached systems; occasional thermonuclear runaways produce symbiotic novae - distant cousins of classical novae.

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