Two distinct sequences of blue straggler stars in the globular cluster M 30

Ferraro, F. R.; Beccari, G.; Dalessandro, E.; Lanzoni, B.; Sills, Alison; Rood, Robert T.; Pecci, F. Fusi; Karakas, Amanda I.; Miocchi, P.; Bovinelli, S

doi:10.1038/nature08607

Cited by 180 publications

(301 citation statements)

References 26 publications

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“…In particular, the ultradense cores of GCs are very efficient "factories" for generating exotic objects, such as low-mass X-ray binaries (LMXBs), cataclysmic variables, blue stragglers, and MSPs (e.g., Bailyn 1995;Verbunt et al 1997;Ferraro et al 2001a). Indeed, these objects are thought to result from the evolution of various kinds of binary systems originated and/or hardened by stellar interactions (e.g., Clark 1975;Hills & Day 1976;Bailyn 1992;Ivanova et al 2008), and are therefore considered powerful diagnostics of GC dynamical evolution (e.g., Ferraro et al 1995;Goodman & Hut 1989;Hut et al 1992;Meylan & Heggie 1997;Pooley et al 2003;Fregeau 2008;Ferraro et al 2009Ferraro et al , 2012.…”

Section: Introductionmentioning

confidence: 99%

Radio Timing and Optical Photometry of the Black Widow System PSR J1518+0204c in the Globular Cluster M5

Pallanca

Ransom

Ferraro

et al. 2014

ApJ

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We report on the determination of astrometric, spin, and orbital parameters for PSR J1518+0204C, a "black widow" binary millisecond pulsar in the globular cluster (GC) M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/Hubble Space Telescope images, we identified a very faint variable star (m F390W 24.8, m F606W 24.3, m F814W 23.1) located at only 0. 25 from the pulsar's timing position. Due to its strong variability, this star is visible only in a subsample of images. However, the light curve obtained folding the available data with the orbital parameters of the pulsar shows a maximum at the pulsar inferior conjunction and a possible minimum at the pulsar superior conjunction. Furthermore, the shape of the optical modulation indicates a heating process possibly due to the pulsar wind. This is the first identification of an optical companion to a black widow pulsar in the dense stellar environment of a GC.

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Section: Introductionmentioning

confidence: 99%

Radio Timing and Optical Photometry of the Black Widow System PSR J1518+0204c in the Globular Cluster M5

Pallanca

Ransom

Ferraro

et al. 2014

ApJ

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“…Terzan 5 is a Galactic globular cluster (GC) located in the inner Galaxy, at RA 17 h 48 m 04.0 s and Dec -24 • 46 45 (in Galactic coordinates: l 3.8 • , b 1.69 • ), at 5.9 kpc from the Sun (Ferraro et al 2009). Terzan 5 hosts the largest population of millisecond pulsars (msPSRs) detected so far (33, Ransom 2008), and it exhibits the highest central stellar density among Galactic GCs (Lanzoni et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Multi-wavelength environment of the Galactic globular cluster Terzan 5

Clapson

Domainko

Jamrozy

et al. 2011

A&A

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Terzan 5 is a Galactic globular cluster exhibiting prominent X-ray and gamma-ray emission. Following the discovery of extended X-ray emission in this object, we explore here archival data at several wavelengths for other unexpected emission features in the vicinity of this globular cluster. Radio data from the Effelsberg 100-m telescope show several extended structures near Terzan 5, albeit with large uncertainties in the flux estimates and no reliable radio spectral index. In particular, a radio source extending from the location of Terzan 5 to the north-west could result from long-term non-thermal electron production by the large population of milli-second pulsars in this globular cluster. Another prominent radio structure close to Terzan 5 may be explained by ionised material produced by a field O star. As for the diffuse X-ray emission found in Terzan 5, its extension appears to be limited to within 2.5 arcmin of the globular cluster and the available multi-wavelength data is compatible with an inverse Compton scenario but disfavours a nonthermal Bremsstrahlung origin.

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“…There is some evidence that both processes could be active in some clusters (Ferraro et al 2009). There are still open issues concerning the surface chemical abundances of BSSs.…”

Section: Application In the Case Of Blue Straggler Starsmentioning

confidence: 99%

Effects of Rotationally Induced Mixing in Compact Binary Systems With Low-Mass Secondaries and in Single Solar-Type Stars

Chatzopoulos¹,

Robinson²,

Wheeler³

2012

ApJ

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Many population synthesis and stellar evolution studies have addressed the evolution of close binary systems in which the primary is a compact remnant and the secondary is filling its Roche lobe, thus triggering mass transfer. Although tidal locking is expected in such systems, most studies have neglected the rotationally induced mixing that may occur. Here we study the possible effects of mixing in mass-losing stars for a range of secondary star masses and metallicities. We find that tidal locking can induce rotational mixing prior to contact and thus affect the evolution of the secondary star if the effects of the Spruit-Tayler dynamo are included both for angular momentum and chemical transport. Once contact is made, the effect of mass transfer tends to be more rapid than the evolutionary timescale, so the effects of mixing are no longer directly important, but the mass-transfer strips matter to inner layers that may have been affected by the mixing. These effects are enhanced for secondaries of 1-1.2 M and for lower metallicities. We discuss the possible implications for the paucity of carbon in the secondaries of the cataclysmic variable SS Cyg and the black hole candidate XTE J1118+480 and for the progenitor evolution of Type Ia supernovae. We also address the issue of the origin of blue straggler stars in globular and open clusters. We find that for models that include rotation consistent with that observed for some blue straggler stars, evolution is chemically homogeneous. This leads to tracks in the H-R diagram that are brighter and bluer than the non-rotating main-sequence turn-off point. Rotational mixing could thus be one of the factors that contribute to the formation of blue stragglers.

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Two distinct sequences of blue straggler stars in the globular cluster M 30

Cited by 180 publications

References 26 publications

Radio Timing and Optical Photometry of the Black Widow System PSR J1518+0204c in the Globular Cluster M5

Radio Timing and Optical Photometry of the Black Widow System PSR J1518+0204c in the Globular Cluster M5

Multi-wavelength environment of the Galactic globular cluster Terzan 5

Effects of Rotationally Induced Mixing in Compact Binary Systems With Low-Mass Secondaries and in Single Solar-Type Stars

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