The Origin and Evolution of Multiple Star Systems

Offner, Stella S. R.; Moe, Maxwell; Kratter, Kaitlin M.; Sadavoy, Sarah; Jensen, Eric L. N.; Tobin, John J.

doi:10.48550/arxiv.2203.10066

Cited by 65 publications

(65 citation statements)

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“…One of the most striking properties of massive stars is their high degree of multiplicity (Sana et al 2012(Sana et al , 2014Moe & Di Stefano 2017;Offner et al 2022). As a consequence, the pres-ence of a companion severely impacts the evolution of these stars (Podsiadlowski et al 1992).…”

Section: Introductionmentioning

confidence: 99%

Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries

Mahy

Sana

Shenar

et al. 2022

A&A

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Context. The quest to detect dormant stellar-mass black holes (BHs) in massive binaries (i.e. OB+BH systems) is challenging; only a few candidates have been claimed to date, all of which must still be confirmed. Aims. To search for these rare objects, we study 32 Galactic O-type stars that were reported as single-lined spectroscopic binaries (SB1s) in the literature. In our sample we include Cyg X-1, which is known to host an accreting stellar-mass BH, and HD 74194, a supergiant fast X-ray transient, in order to validate our methodology. The final goal is to characterise the nature of the unseen companions to determine if they are main-sequence (MS) stars, stripped helium stars, triples, or compact objects such as neutron stars (NSs) or stellar-mass BHs. Methods. After measuring radial velocities and deriving orbital solutions for all the systems in our sample, we performed spectral disentangling to extract putative signatures of faint secondary companions from the composite spectra. We derived stellar parameters for the visible stars and estimated the mass ranges of the secondary stars using the binary mass function. Variability observed in the photometric TESS light curves was also searched for indications of the presence of putative companions, degenerate or not. Results. In 17 of the 32 systems reported as SB1s, we extract secondary signatures, down to mass ratios of ∼ 0.15. For the 17 newly detected double-lined spectroscopic binaries (SB2s), we derive physical properties of the individual components and discuss why they have not been detected as such before. Among the remaining systems, we identify nine systems with possible NS or low-mass MS companions. For Cyg X-1 and HD 130298, we are not able to extract any signatures for the companions, and the minimum masses of their companions are estimated to be about 7 M . Our simulations show that secondaries with such a mass should be detectable from our dataset, no matter their nature: MS stars, stripped helium stars or even triples. While this is expected for Cyg X-1, confirming our methodology, our simulations also strongly suggest that HD 130298 could be another candidate to host a stellar-mass BH. Conclusions. The quest to detect dormant stellar-mass BHs in massive binaries is far from over, and many more systems need to be scrutinised. Our analysis allows us to detect good candidates, but confirming the BH nature of their companions will require further dedicated monitorings, sophisticated analysis techniques, and multi-wavelength observations.

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Section: Introductionmentioning

confidence: 99%

Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries

Mahy

Sana

Shenar

et al. 2022

A&A

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“…Do small stellar groups arise from a simple hierarchical collapse of a clump, or are their spatial extent and multiplicity more compatible with an association of clumps that would result from the fragmentation of a filament, with each of these clumps in turn collapsing hierarchically or monolithically? Most probably, both scenarios exist (Offner et al 2022): the UWPs and large NESTs may result from the fragmentation of filaments (scale > 13 kAU), and the hierarchical fragmentation of clumps may proceed at smaller range, whereas disc fragmentation around YSOs may explain the very close stellar systems (scale < 100 AU). Our methodology is suitable for studying the spatial characteristics of hierarchical fragmentation, but gives no indication of the temporal aspects.…”

Section: Discussionmentioning

confidence: 99%

A graph-theory-based multi-scale analysis of hierarchical cascade in molecular clouds

Thomasson

Joncour

Moraux

et al. 2022

A&A

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Context. The spatial properties of small star clusters suggest that they may originate from a fragmentation cascade starting from molecular cloud, of which there might be traces found at spatial scales up to a few tens of thousands of astronomical units (kAU). Aims. Our goal is to investigate the multi-scale spatial structure of gas clumps, to probe the existence of a hierarchical cascade over a range of characteristic spatial scales, and to evaluate its possible link with star production in terms of multiplicity. Methods. From the Herschel emission maps of NGC 2264 at [70, 160, 250, 350, 500] µm, clumps are extracted using getsf software at each of the associated spatial resolutions (respectively [8.4, 13.5, 18.2, 24.9, 36.3]"). Using the spatial distribution of these clumps and the class 0/I young stellar object (YSO) from Spitzer data, we developed a graph-theoretic analysis to represent the multi-scale structure of the cloud as a connected network. This network is organised in levels, and each level represents a characteristic scale among the available spatial scales. A link is created between two nodes which could be either a clump or a YSO from two different levels if their footprints overlap with each other. A parent node is then associated with a child node from a lower scale. The way in which the network subdivides scale after scale is compared with a geometric model that we have developed. This model generates extended objects that have a particularity in that they are geometrically constrained and subdivide along the scales following a fractal law. This graph-theoretic representation allows us to develop new statistical metrics and tools aiming at characterising, in a quantitative way, the multi-scale nature of molecular clouds. Results. We obtain three classes of multi-scale structure in NGC 2264 according to the number of nodes produced at the deepest level (called graph-sinks): hierarchical (several graph-sinks), linear (a single graph-sink with at most a single parent at each level), and isolated (no connection to any other node). The class of structure is strongly correlated with the column density N H 2 of NGC 2264. The hierarchical structures dominate the regions whose column density exceeds N H 2 = 6 × 10 22 cm −2 . Although the latter are in the minority, namely 23% of the total number of structures, they contain half of the class 0/I YSOs, proving that they are highly efficient in producing stars. We define a novel statistical metric, the fractality coefficient F , corresponding to the fractal index that an equivalent population of clumps would have if they were generated by an ideal fractal cascade. For NGC 2264, over the whole range of spatial scales (1.4-26 kAU), this coefficient is globally estimated to be F = 1.45±0.12 and its dispersion suggests that the cascade may depend on local physical conditions. However, a single fractal index is not the best fit for the NGC 2264 data because the hierarchical cascade starts at a 13 kAU characteristic spatial scale. Conclusions. Our novel methodo...

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“…For a low-mass binary from such a scenario, the secondary star is younger than the primary star by a few million years. For a thorough discussion of the formation of twin binaries, we refer to Bate & Bonnell (1997), Bate (1998Bate ( , 2018, Tokovinin (1992Tokovinin ( , 2000, Tokovinin & Moe (2020), Simon & Obbie (2009), and Offner et al (2016, 2022.…”

Section: Implications For the Excess Of Type-g Binaries With Equal Co...mentioning

confidence: 99%

Mass-ratio Distribution of Binaries from the LAMOST-MRS Survey

Liu

et al. 2022

ApJ

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Binary evolution leads to the formation of important objects that are crucial for the development of astrophysics, but the statistical properties of binary populations are still poorly understood. The LAMOST-MRS has provided a large sample of stars to study the properties of binary populations, especially for the mass-ratio distributions and binary fractions. We have devised a peak amplitude ratio (PAR) approach to derive the mass ratio of a binary system based on results obtained from its spectrum. By computing a cross-correlation function, we established a relation between the derived mass ratio and the PARs of the binary systems. By using spectral observations obtained from LAMSOT DR6 and DR7, we applied the PAR approach to form distributions of the derived mass ratio of the binary systems to the spectral types. We selected the mass ratio within the range of 0.6−1.0 to investigate the mass-ratio distribution. Through a power-law fitting, we obtained power index γ values of −0.42 ± 0.27, 0.03 ± 0.12, and 2.12 ± 0.19 for the A-, F-, and G-type stars identified in the sample, respectively. The derived γ-values display an increasing trend toward lower primary star masses, and G-type binaries tend to be twins more frequently. The close binary fractions (for P ≲ 150 days and q ≳ 0.6) in our sample for A, F, and G binaries are 7.6% ± 0.5%, 4.9% ± 0.2%, and 3.7% ± 0.1%, respectively. Note that the PAR approach can be applied to large spectroscopic surveys of stars.

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The Origin and Evolution of Multiple Star Systems

Cited by 65 publications

References 0 publications

Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries

Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries

A graph-theory-based multi-scale analysis of hierarchical cascade in molecular clouds

Mass-ratio Distribution of Binaries from the LAMOST-MRS Survey

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