The kinematics of the Scorpius-Centaurus OB association from Gaia DR1

Wright, N. J.; Mamajek, Eric E.

doi:10.1093/mnras/sty207

Cited by 139 publications

(176 citation statements)

References 93 publications

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“…(c) RV unknown, Monte Carlo simulation with 3 million runs drawing velocity from Maxwellian distribution (Tetzlaff et al 2010). (d) from Wright & Mamajek (2018) with a radius of ∼ 30 pc for UCL (±13 • ), ∼ 23.25 pc for LCC, and 17 pc for UpSco, 1.5 times the scale length of the half-mass radius (Wright & Mamajek 2018). (Zehe et al 2018), the input, output, and total log likelihoods of this case are still the highest, and the approach between runaway and pulsar is the smallest -hence, our best case.…”

Section: The New Case: ζ Oph and Psr B1706-16mentioning

confidence: 75%

“…). (l) New Gaia astrometry for UpSco with a radius of 17.1 pc(Wright & Mamajek 2018), which is well reliable. (k,l) The systematic offset of −0.029 mas to the parallax zero-point in Gaia DR2 data) would be only 1 pc here, i.e.…”

mentioning

confidence: 93%

“…Several SNe from Scorpius-Centaurus-Lupus should have produced runaways, neutron stars and 60 Fe in the last few Myr (Maiz-Apellaniz 2001): by comparing the current mass functions of the nearby (∼ 115 − 136 pc) Upper-Centaurus-Lupus (UCL) and Lower-Centaurus-Crux (LCC) sub-groups of the Scorpius-Centaurus-Lupus association (Wright & Mamajek 2018) with the initial mass function (IMF), ∼ 10 massive stars are considered missing from UCL, ∼ 6 from LCC (Fuchs et al 2006, B16). The IMF predicts the most likely main-sequence masses of the ∼ 16 missing stars: ∼ 8.8 − 19.9 M (B16).…”

Section: Introduction: 60 Fe On Earthmentioning

confidence: 99%

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A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

Neuhäuser

Gießler

Hambaryan

2019

Monthly Notices of the Royal Astronomical Society

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The detection of ∼ 1.5−3.2 Myr old 60 Fe on Earth indicates recent nearby core-collapse supernovae. For supernovae in multiple stars, the primary stars may become neutron stars, while former companions may become unbound and become runaway stars. We wrote software for tracing back the space motion of runaway and neutron stars to young associations of massive stars. We apply it here to the nearby young Scorpius-Centaurus-Lupus groups, all known runaway stars possibly coming from there, and all 400 neutron stars with known transverse velocity. We find kinematic evidence that the runaway ζ Oph and the radio pulsar PSR B1706-16 were released by a supernova in a binary 1.78 ± 0.21 Myr ago at 107 ± 4 pc distance (for pulsar radial velocity 260 ± 43 km/s); association age and flight time determine the progenitor mass (16-18 M ), which can constrain supernova nucleosynthesis yields and 60 Fe uptake on Earth. In addition, we notice that the only high-mass X-ray binary in Scorpius-Centaurus-Lupus (1H11255-567 with µ 1 and µ 2 Cru) may include a neutron star formed in another SN, up to ∼ 1.8 Myr ago at 89 − 112 pc, i.e. also yielding 60 Fe detectable on Earth. Our scenario links 60 Fe found on Earth to one or two individual supernovae in multiple stars.

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Section: The New Case: ζ Oph and Psr B1706-16mentioning

confidence: 75%

mentioning

confidence: 93%

Section: Introduction: 60 Fe On Earthmentioning

confidence: 99%

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A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

Neuhäuser

Gießler

Hambaryan

2019

Monthly Notices of the Royal Astronomical Society

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“…Many young stars within 100 pc of the sun are categorized into members of open clusters and nearby young moving groups (NYMGs) . Clusters and moving groups are thought to be born in molecular clouds, and slowly disperse over millions of years due to feedback between the stars and material left over from the star formation process (Wright & Mamajek 2018). Before dispersing into the galaxy, the young stars form an association, a group of stars which share similar kinematics.…”

Section: Integrations With Impulses: Distance To 'Oumuamua's Origin Pmentioning

confidence: 99%

The Dynamics of Interstellar Asteroids and Comets within the Galaxy: An Assessment of Local Candidate Source Regions for 1I/’Oumuamua and 2I/Borisov

Hallatt

Wiegert

2020

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The velocity of interstellar asteroid 'Oumuamua with respect to the Local Standard of Rest of our Galaxy is low, which implies it is young, at least if it was ejected during its host star's protoplanetary phase. With this young age as our hypothesis, we assess possible origin systems for the interstellar asteroid in two ways.First, by modelling 'Oumuamua's past trajectory under the influence of the galactic tide and the disk heating (ie. scattering) to assess how far back one can reliably expect to trace its orbit. The stochastic nature of disk heating means that a back integration of 'Oumuamua can only expect to be accurate to within 15 pc and 2 km/s at -10 Myr, 100 pc and 5 km/s at -50 Myr, and 400 pc and 10 km/s at -100 Myr, sharply limiting our ability to determine a precise origin. However, we can show that if 'Oumuamua was ejected at low (∼ 1 km/s) speed, as is likely for most ejection processes, 'Oumuamua's origin system is currently within 1 kpc of Earth. This would place the origin system nearby within the local Orion Arm, and thus relatively easily accessible to telescopic study. This provides strong motivation for continued efforts to determine 'Oumuamua's place of origin, because that system could be studied in detail and shed light on the nature of this unusual asteroid.Second, with this initial assessment in hand, we perform a backwards integration of 'Oumuamua's trajectory accounting for uncertainty in its and the candidate source regions' speed and position where possible, to assess potential candidate regions. The Gaia DR2 catalog and the SIMBAD catalog were considered, with particular emphasis on young systems as detailed in the Catalog of Suspected Nearby Young Stars ) and moving groups as compiled in Gagné et al. (2018). Though disk heating prevents making any but a statistical link to local star-forming regions and moving groups, our best candidates are the Carina and Columba moving groups, the Lupus SFR, the T-Tau stars V391 Ori and BD+11 414, and the M dwarf GJ 1167 A. 'Oumuamua passed through at least a considerable subset of the Carina and Columba moving groups at a time comparable to their ages, making it perhaps the most plausible source region, if the asteroid was ejected by the planet-forming process.During the writing of this paper, a second interstellar comet 2I/Borisov was discovered. Though unlikely to be young due to its high velocity with respect to the LSR, we performed a similar analysis and found three stars in the Ursa Major group (GJ 4384, EV Lac, and GJ 102), one brown dwarf of the AB Dor group (2MASS J03552337+113343), and 8 Gaia DR2 stars (including EV Lac) to have plausible encounters at speeds <30 kms −1 and within 2 pc. We do not find any plausible encounters at speeds lower than 13 kms −1 .

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“…The detailed investigation into the origin and evolution of the OB association Cygnus OB2 by Wright et al (2014Wright et al ( , 2015Wright et al ( , 2016 found no evidence of a violent relaxation event and instead found that Cygnus OB2 was likely always an association and has not undergone significant dynamical evolution. Similarly, Wright & Mamajek (2018) used the first Gaia data release to show that the Sco-Cen OB association was most likely formed in a highly substructured state with multiple small-scale star formation events rather than a single, monolithic burst of star formation. Another study of 18 nearby OB associations (although different associations to those analysed in Ward & Kruijssen 2018), using the first Gaia data release found little evidence of systematic expansion of OB associations (Mel'nik & Dambis 2017).…”

Section: Introductionmentioning

confidence: 99%

Not all stars form in clusters – Gaia-DR2 uncovers the origin of OB associations

Ward

Kruijssen

Rix

2020

Monthly Notices of the Royal Astronomical Society

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Historically, it has often been asserted that most stars form in compact clusters. In this scenario, present-day gravitationally-unbound OB associations are the result of the expansion of initially gravitationally-bound star clusters. However, this paradigm is inconsistent with recent results, both theoretical and observational, that instead favour a hierarchical picture of star formation in which stars are formed across a continuous distribution of gas densities and most OB associations never were bound clusters. Instead they are formed in-situ as the lowdensity side of this distribution, rather than as the remnants of expanding clusters. We utilise the second Gaia data release to quantify the degree to which OB associations are undergoing expansion and, therefore, whether OB associations are the product of expanding clusters, or whether they were born in-situ, as the large-scale, globally-unbound associations that we see today. We find that the observed kinematic properties of associations are consistent with highly substructured velocity fields and additionally require some degree of localised expansion from sub-clusters within the association. While most present-day OB associations do exhibit low levels of expansion, there is no significant correlation between radial velocity and radius. Therefore, the large-scale structure of associations is not set by the expansion of clusters, rather it is a relic of the molecular gas cloud from which the association was formed. This finding is inconsistent with a monolithic model of association formation and instead favours a hierarchical model, in which OB associations form in-situ, following the fractal structure of the gas from which they form.

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The kinematics of the Scorpius-Centaurus OB association from Gaia DR1

Cited by 139 publications

References 93 publications

A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

The Dynamics of Interstellar Asteroids and Comets within the Galaxy: An Assessment of Local Candidate Source Regions for 1I/’Oumuamua and 2I/Borisov

Not all stars form in clusters – Gaia-DR2 uncovers the origin of OB associations

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