367 citations · 6.1k across the 116 of their papers we have counts for
38 papers · 1 filter
Revisiting the Evidence for Double Sequences of Blue Straggler Stars in Globular Clusters
Gourav Kumawat, Craig O. Heinke, Alison Sills +5
Blue straggler stars (BSSs) are believed to form through mass transfer in binary systems or stellar collisions. The reported presence of double BSS sequences in some globular clust…
Massive interacting binaries as an enrichment source for multiple populations in star clusters
Michelle Nguyen, Alison Sills
We present a suite of binary evolution models with massive primaries (10 M 40 M) and periods and mass ratios chosen such that the systems undergo non-cons…
Fast rotating Blue Stragglers prefer loose clusters
Francesco R. Ferraro, Alessio Mucciarelli, Barbara Lanzoni +9
Blue stragglers are anomalously luminous core hydrogen-burning stars formed through mass-transfer in binary/triple systems and stellar collisions. Their physical and evolutionary p…
Implementing Primordial Binaries in Simulations of Star Cluster Formation with a Hybrid MHD and Direct N-Body Method
Claude Cournoyer-Cloutier, Aaron Tran, Sean Lewis +6
The fraction of stars in binary systems within star clusters is important for their evolution, but what proportion of binaries form by dynamical processes after initial stellar acc…
Chemical abundances along the 1G sequence of the chromosome maps: The Globular Cluster NGC 3201
A. F. Marino, A. P. Milone, A. Sills +10
The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the "chromosome map" (ChM) diagnosti…
Constraining Mass Transfer Histories of Blue Straggler Stars with COS Spectroscopy of White Dwarf Companions
Natalie M. Gosnell, Emily M. Leiner, Robert D. Mathieu +4
Recent studies show that the majority of blue straggler stars (BSSs) in old open clusters are formed through mass transfer from an evolved star onto a main-sequence companion, resu…
Discovery of a double Blue Straggler sequence in M15: new insight into the core-collapse process
Giacomo Beccari, Francesco R. Ferraro, Emanuele Dalessandro +8
In this paper we report on the discovery of a double blue straggler star (BSS) sequence in the core of the core-collapsed cluster M15 (NGC 7078). We performed a detailed photometri…
Observations of Spin-Down in Post-Mast-Transfer Stars and the Possibility for Blue Straggler Gyrochronology
Emily Leiner, Robert Mathieu, Natalie Gosnell +1
Blue stragglers and other mass transfer/collision products are likely born with rapid rotation rates due to angular momentum transfer during mass-transfer, merger or collisional fo…
Constraints on blue straggler formation mechanisms in Galactic globular clusters from proper motion velocity distributions
N. W. C. Leigh, T. Panurach, M. Simunovic +10
For a sample of 38 Galactic globular clusters (GCs), we confront the observed distributions of blue straggler (BS) proper motions and masses (derived from isochrone fitting) from t…
On the Origin of Sub-subgiant Stars. I. Demographics
Aaron M. Geller, Emily M. Leiner, Andrea Bellini +8
Sub-subgiants are stars observed to be redder than normal main-sequence stars and fainter than normal subgiant (and giant) stars in an optical color-magnitude diagram. The red stra…
On the Origin of Sub-subgiant Stars. III. Formation Frequencies
Aaron M. Geller, Emily M. Leiner, Sourav Chatterjee +3
Sub-subgiants are a new class of stars that are optically redder than normal main-sequence stars and fainter than normal subgiant stars. Sub-subgiants, and the possibly related red…
Observational constraints on star cluster formation theory - I. The mass-radius relation
S. Pfalzner, H. Kirk, A. Sills +5
Stars form predominantly in groups usually denoted as clusters or associations. The observed stellar groups display a broad spectrum of masses, sizes and other properties, so it is…
Implications for the Formation of Blue Straggler Stars from HST Ultraviolet Observations of NGC 188
Natalie M. Gosnell, Robert D. Mathieu, Aaron M. Geller +3
We present results of a Hubble Space Telescope far-ultraviolet (FUV) survey searching for white dwarf (WD) companions to blue straggler stars (BSSs) in open cluster NGC 188. The ma…
The state of globular clusters at birth II: primordial binaries
Nathan W. C. Leigh, Mirek Giersz, Michael Marks +5
(abridged) In this paper, we constrain the properties of primordial binary populations in Galactic globular clusters using the MOCCA Monte Carlo code for cluster evolution. Our res…
The Blue Straggler Star Population in NGC 1261: Evidence for a Post-Core-Collapse Bounce State
Mirko Simunovic, Thomas H. Puzia, Alison Sills
We present a multi-passband photometric study of the Blue Straggler Star (BSS) population in the Galactic globular cluster (GC) NGC\,1261, using available space- and ground-based s…
Models of Individual Blue Stragglers
Alison Sills
This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all…
Detection of white dwarf companions to blue stragglers in the open cluster NGC 188: direct evidence for recent mass transfer
Natalie M. Gosnell, Robert D. Mathieu, Aaron M. Geller +3
Several possible formation pathways for blue straggler stars have been developed recently, but no one pathway has yet been observationally confirmed for a specific blue straggler.…
Double Blue Straggler sequences in GCs: the case of NGC 362
E. Dalessandro, F. R. Ferraro, D. Massari +8
We used high-quality images acquired with the WFC3 on board the HST to probe the blue straggler star (BSS) population of the Galactic globular cluster NGC 362. We have found two di…
Overview of the Massive Young Star-Forming Complex Study in Infrared and X-ray (MYStIX) Project
Eric D. Feigelson, Leisa K. Townsley, Patrick S. Broos +16
MYStIX (Massive Young Star-Forming Complex Study in Infrared and Xray) seeks to characterize 20 OB-dominated young clusters and their environs at distances d < 4 kpc using imaging…
The state of globular clusters at birth: emergence from the gas-embedded phase
Nathan W. C. Leigh, Mirek Giersz, Jeremy J. Webb +4
In this paper, we discuss the origin of the observed correlation between cluster concentration c and present-day mass function (PDMF) slope α reported by De Marchi, Paresce & Pulon…
The radius discrepancy in low mass stars: single vs. binaries
F. Spada, P. Demarque, Y. -C. Kim +1
A long-standing issue in the theory of low mass stars is the discrepancy between predicted and observed radii and effective temperatures. In spite of the increasing availability of…
Modifying two-body relaxation in N-body systems by gas accretion
Nathan W. C. Leigh, Alison Sills, Torsten Boker
We consider the effects that accretion from the interstellar medium onto the particles of an N-body system has on the rate of two-body relaxation. To this end, we derive an accreti…
Mock Observations of Blue Stragglers in Globular Cluster Models
Alison Sills, Evert Glebbeek, Sourav Chatterjee +1
We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters, and then used observational methods to determine the number of blue stragglers…
Stellar Collisions and Blue Straggler Stars in Dense Globular Clusters
Sourav Chatterjee, Frederic A. Rasio, Alison Sills +1
Blue straggler stars (BSS) are abundantly observed in all Galactic globular clusters (GGC) where data exist. However, observations alone cannot reveal the relative importance of va…