Results 1 to 10 of about 94 (78)

Fast rotating blue stragglers prefer loose clusters. [PDF]

Nat Commun, 2023
Blue stragglers are anomalously luminous core hydrogen-burning stars formed through mass-transfer in binary/triple systems and stellar collisions. Their physical and evolutionary properties are largely unknown and unconstrained.
Ferraro FR, Mucciarelli A, Lanzoni B, Pallanca C, Cadelano M, Billi A, Sills A, Vesperini E, Dalessandro E, Beccari G, Monaco L, Mateo M.   +11 more
europepmc   +2 more sources

A binary-related origin mediated by environmental conditions for blue straggler stars. [PDF]

Nat Commun
Blue stragglers are anomalously massive core hydrogen-burning stars that, according to the theory of single star evolution, should not exist. They are suspected to form in mass-enhancement processes, involving binary evolution or stellar collisions.
Ferraro FR, Lanzoni B, Vesperini E, Dalessandro E, Cadelano M, Pallanca C, Beccari G, Nardiello D, Libralato M, Piotto G.   +9 more
europepmc   +2 more sources

On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856

The Astrophysical Journal, 2023
The detection of split main sequences (MSs) associated with young clusters (≲600 Myr) has attracted a lot of attention. A prevailing scenario is that a bimodality of stellar rotation distribution drives the bifurcation of the MS. Nevertheless, the origin
Li Wang, Chengyuan Li, Long Wang, Chenyu He, Chen Wang   +4 more
doaj   +1 more source

Fast-rotating Blue Straggler Stars in the Globular Cluster NGC 3201

The Astrophysical Journal, 2023
We used high-resolution spectra acquired with the Magellan Telescope to measure radial and rotational velocities of approximately 200 stars in the Galactic globular cluster NGC 3201.
Alex Billi, Francesco R. Ferraro, Alessio Mucciarelli, Barbara Lanzoni, Mario Cadelano, Lorenzo Monaco, Mario Mateo, John I. Bailey III, Megan Reiter, Edward W. Olszewski   +9 more
doaj   +1 more source

Variable Blue Straggler Stars in the Open Cluster NGC 6819 Observed in the Kepler “Superstamp” Field

The Astronomical Journal, 2023
NGC 6819 is an open cluster of age 2.4 Gyr that was in the NASA Kepler spacecraft’s field of view from 2009 to 2013. The central part of the cluster was observed in a 200 × 200 pixel “superstamp” during these four years in 30 minute cadence photometry ...
Joyce A. Guzik, Andrzej S. Baran, Sachu Sanjayan, Péter Németh, Anne M. Hedlund, Jason Jackiewicz, Lori R. Dauelsberg   +6 more
doaj   +1 more source

Empirical Measurement of the Dynamical Ages of Three Globular Clusters and Some Considerations on the Use of the Dynamical Clock

The Astrophysical Journal, 2023
We have used the “dynamical clock” to measure the level of dynamical evolution reached by three Galactic globular clusters (namely, NGC 3201, NGC 6316, and NGC 6440).
Francesco R. Ferraro, Barbara Lanzoni, Enrico Vesperini, Mario Cadelano, Dan Deras, Cristina Pallanca   +5 more
doaj   +1 more source

M67 Blue Stragglers with High-resolution Infrared Spectroscopy

The Astronomical Journal, 2023
We report on the first detailed infrared chemical analysis of five binary members (S277, S997, S975, S1031, and S1195) in the open cluster M67 (NGC 2682).
K. E. Brady, C. Sneden, C. A. Pilachowski, Melike Afşar, G. N. Mace, D. T. Jaffe, N. M. Gosnell, R. Seifert   +7 more
doaj   +1 more source

A Wide Metallicity Range for Gyr-old Stars in the Nuclear Star Cluster

The Astrophysical Journal Letters, 2023
We report metallicities for three ∼Gyr-old stars in the Milky Way nuclear star cluster (NSC) using high-resolution near-infrared spectroscopy. We derive effective temperatures from a calibration with Sc line strength, which yields results in good ...
B. Thorsbro, R. Forsberg, G. Kordopatis, A. Mastrobuono-Battisti, R. P. Church, R. M. Rich, N. Ryde, M. Schultheis, S. Nishiyama   +8 more
doaj   +1 more source

On the Variability of Blue Straggler Stars in the Globular Cluster M53 [PDF]

Journal of Astronomy and Space Sciences, 1998
We present the results of a search for photometric variable blue straggler stars (BSSs) in the globular cluster M53. Six of the 151 probable BSSs are identified as variable candidates based on the robust variable star detection technique of Welch ...
Soo-Chang Rey, Young-Wook Lee, Yong-Ik Byun   +2 more
doaj  

UOCS-IX. AstroSat/UVIT Study of the Open Cluster NGC 2818: Blue Stragglers, Yellow Stragglers, Planetary Nebula, and their Membership

The Astrophysical Journal, 2023
We present the first far-UV (FUV) imaging results of the intermediate-age Galactic open cluster NGC 2818 that has a planetary nebula (PN) within the field using images taken from the Ultra Violet Imaging Telescope (UVIT) aboard AstroSat.
Sharmila Rani, Gajendra Pandey, Annapurni Subramaniam, N. Kameswara Rao   +3 more
doaj   +1 more source