Results 1 to 10 of about 141 (117)

Fast rotating blue stragglers prefer loose clusters [PDF]

Nature Communications, 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.
Francesco R. Ferraro, Alessio Mucciarelli, Barbara Lanzoni, Cristina Pallanca, Mario Cadelano, Alex Billi, Alison Sills, Enrico Vesperini, Emanuele Dalessandro, Giacomo Beccari, Lorenzo Monaco, Mario Mateo   +11 more
doaj   +2 more sources

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

Nature Communications
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.
Francesco R. Ferraro, Barbara Lanzoni, Enrico Vesperini, Emanuele Dalessandro, Mario Cadelano, Cristina Pallanca, Giacomo Beccari, Domenico Nardiello, Mattia Libralato, Giampaolo Piotto   +9 more
doaj   +2 more sources

Are Blue Straggler Stars a Hidden Clue? Intriguing Discovery in Pityriasis Rubra Pilaris Under UV-Induced Fluorescence Dermoscopy [PDF]

Dermatology Practical & Conceptual
Divya Madonna Dsouza, Jacintha Martis, Ramesh Bhat M, Michelle Serene Fernandes, Rochelle Cheryl Monteiro, Jyothi Jayaraman   +5 more
doaj   +2 more sources

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

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

WOCS 4540: Detailed Analysis of a very Long Orbital Period Blue Straggler

The Astrophysical Journal, 2023
WOCS 4540 is the longest orbital period ( P _orb = 3030 days) blue straggler star (BSS)—white dwarf (WD) pair in the old open cluster NGC 188. It also contains one of the most luminous BSS in the cluster.
Meng Sun, Robert D. Mathieu
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

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

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

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