The Multiplicity of Pre–Main‐Sequence Stars in Southern Star‐forming Regions

Ghez, A. M.; McCarthy, D. W.; Patience, J.; Beck, Tracy

doi:10.1086/304031

Cited by 216 publications

(267 citation statements)

References 24 publications

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“…Multiple stellar systems are abundant in our solar neighbourhood (Duquennoy & Mayor 1991;Raghavan et al 2010) and in our galaxy; they can be found in a variety environments, from young star-forming regions (SFRs; Ghez et al 1997;Nguyen et al 2012) to older, sparser populations such as globular clusters (Sollima et al 2007). These numerous multiple systems appear to be the default of nature and therefore studying them is studying a key ingredient of star formation and evolution.…”

Section: Introductionmentioning

confidence: 99%

Search for associations containing young stars (SACY)

Elliott

Bayo

Melo

et al. 2014

A&A

129

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Context. Dynamically undisrupted, young populations of stars are crucial in studying the role of multiplicity in relation to star formation. Loose nearby associations provide us with a great sample of close (<150 pc) pre-main sequence (PMS) stars across the very important age range (≈5−70 Myr) to conduct such research. Aims. We characterize the short period multiplicity fraction of the search for associations containing young stars (SACY) sample, accounting for any identifiable bias in our techniques and present the role of multiplicity fractions of the SACY sample in the context of star formation. Methods. Using the cross-correlation technique we identified double-lined and triple-lined spectroscopic systems (SB2/SB3s), in addition to this we computed radial velocity (RV) values for our subsample of SACY targets using several epochs of Fiber-fed Extended Range Optical Spectrograph (FEROS) and Ultraviolet and Visual Echelle Spectrograph (UVES) data. These values were used to revise the membership of each association that was then combined with archival data to determine significant RV variations across different data epochs characteristic of multiplicity; single-lined multiple systems (SB1). Results. We identified seven new multiple systems (SB1s: 5, SB2s: 2). We find no significant difference between the short period multiplicity fraction (F m ) of the SACY sample and that of close star-forming regions (≈1−2 Myr) and the field (F m ≤ 10%). These are seen both as a function of age and as a function of primary mass, M 1 , in the ranges P [1:200 day] and M 2 [0.08 M -M 1 ], respectively. Conclusions. Our results are consistent with the picture of universal star formation, when compared to the field and close star-forming regions (SFRs). We comment on the implications of the relationship between increasing multiplicity fraction with the primary mass within the close companion range in relation to star formation.

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Section: Introductionmentioning

confidence: 99%

Search for associations containing young stars (SACY)

Elliott

Bayo

Melo

et al. 2014

A&A

129

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“…For this purpose, a sample comprising 49 objects was selected from the binary surveys of Reipurth & Zinnecker (1993) and Ghez et al (1997).…”

Section: Introductionmentioning

confidence: 99%

Pre-Main Sequence Binaries with Aligned Disks?

Wolf

Stecklum

Henning³

2001

Symp. - Int. Astron. Union

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Abstract. We present the results of a study performed with the goal to investigate whether low-mass pre-main sequence binary stars are formed by multiple fragmentation or via stellar capture. If binaries form preferentially by fragmentation, we expect their disks to be co-planar. On the other hand, the capture scenario will lead to a random distribution of disk orientations. We performed near-infrared polarization measurements of 49 young close binary stars in the K band with SOFI at the NTT. The near-infrared excess radiation of the targets mostly point to the presence of disks. For a major fraction of the sample, evidence for disks is also obvious from other features (outflows, jets, Herbig-Haro objects). We derived the disk orientation from the orientation of the polarization vector of both components of each binary. This statistical study allows to test which hypothesis (co-planarity, random orientation) is consistent with the observed distribution of polarimetric position angles. We find evidence that the disks are preferentially aligned.

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“…However, several studies (Ghez et al 1997;White & Ghez 2001;Cieza et al 2009;Duchêne 2010;Kraus et al 2012) have found protoplanetary disk fractions are lower for young ( 5 Myr) binary systems with a<50 au than for single stars or wider binaries. With the exception of Kraus et al (2012), these studies were not sensitive to the tight binary systems to which our study was especially sensitive.…”

Section: Sample Sensitivity To Companionsmentioning

confidence: 99%

Searching for Spectroscopic Binaries Within Transition Disk Objects*

Kohn

Shkolnik

Weinberger

et al. 2016

ApJ

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Transition disks (TDs) are intermediate stage circumstellar disks characterized by an inner gap within the disk structure. To test whether these gaps may have been formed by closely orbiting, previously undetected stellar companions, we collected high-resolution optical spectra of 31 TD objects to search for spectroscopic binaries (SBs). Twenty-four of these objects are in Ophiuchus and seven are within the Coronet, Corona Australis, and Chameleon I star-forming regions. We measured radial velocities for multiple epochs, obtaining a median precision of 400 ms −1 . We identified double-lined SB SSTc2d J163154.7-250324 in Ophiuchus, which we determined to be composed of a K7(±0.5) and a K9(±0.5) star, with orbital limits of a<0.6 au and P<150 days. This results in an SB fraction of -+ 0.04 0.03 0.12 in Ophiuchus, which is consistent with other spectroscopic surveys of non-TD objects in the region. This similarity suggests that TDs are not preferentially sculpted by the presence of close binaries and that planet formation around close binaries may take place over similar timescales to that around single stars.

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The Multiplicity of Pre–Main‐Sequence Stars in Southern Star‐forming Regions

Cited by 216 publications

References 24 publications

Search for associations containing young stars (SACY)

Search for associations containing young stars (SACY)

Pre-Main Sequence Binaries with Aligned Disks?

Searching for Spectroscopic Binaries Within Transition Disk Objects*

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