Publications related to Chemically peculiar star

HD 213258: A new rapidly oscillating, super slowly rotating, strongly magnetic Ap star in a spectroscopic binary

We report on HD 213258, an Ap star that we recently identified as presenting a unique combination of rare, remarkable properties. Our study of this star is based on ESPaDOnS Stokes I and V data obtained at seven epochs spanning a time interval slightly sho ...

EDP SCIENCES S A2023

Analysis of accretion disc structure and stability using open code for vertical structure

Pascale Jablonka

Detailed chemical abundances of very metal-poor (VMP; [Fe/H] < -2) stars are important for better understanding the first stars, early star formation, and chemical enrichment of galaxies. Big on-going and coming high-resolution spectroscopic surveys provid ...

OXFORD UNIV PRESS2023

HD 60431, the CP2 star with the shortest rotational period Physical parameters and period analysis

Pierre North

Context. CP2 stars show periodic photometric, spectroscopic, and magnetic variations with the rotational period. They are generally slow rotators, with rotational periods exceeding half a day, except for the late B-type star HD 60431, which has an unusuall ...

EDP SCIENCES S A2022

The first generations of stars in the Local Group

Romain Ely Roland Lucchesi

The different projects of this thesis contribute to improving our understanding of the early chemical evolution of the galaxies. The standard cosmological model states an hierarchical formation of the galaxies, the dwarf galaxies being the first stellar sy ...

EPFL2022

Discovery of a Binary-origin Classical Cepheid in a Binary System with a 59 day Orbital Period

Richard Irving Anderson

We report the discovery of a surprising binary configuration of the double-mode Cepheid OGLE-LMC-CEP-1347 pulsating in the first (P-1= 0.690 days) and second-overtone (P-2= 0.556 days) modes. The orbital period (P-orb= 59 days) of the system is five times ...

Iop Publishing Ltd2022

Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy

Pascale Jablonka, Yves Revaz

Stellar prolate rotation in dwarf galaxies is rather uncommon, with only two known galaxies in the Local Group showing such feature (Phoenix and And II). Cosmological simulations show that in massive early-type galaxies prolate rotation likely arises from ...

OXFORD UNIV PRESS2021

Kinematic and metallicity properties of the Aquarius dwarf galaxy from FORS2 MXU spectroscopy

Pascale Jablonka

Context. Dwarf galaxies found in isolation in the Local Group (LG) are unlikely to have interacted with the large LG spirals, and therefore environmental effects such as tidal and ram-pressure stripping should not be the main drivers of their evolution. Ai ...

EDP SCIENCES S A2020

Spectroscopic Orbits Of Three Dwarf Barium Stars

Pierre North

Barium stars are thought to result from binary evolution in systems wide enough to allow the more massive component to reach the asymptotic giant branch and eventually become a CO white dwarf. While Ba stars were initially known only among giant or subgian ...

OBSERVATORY2020

Impact of a companion and of chromospheric emission on the shape of chromosome maps for globular clusters

Carmela Lardo

Context. Globular clusters (GCs) host multiple populations of stars that are well-separated in a photometric diagram - the chromosome map - built from specific Hubble Space Telescope (HST) filters. Stars from different populations feature at various locati ...

EDP SCIENCES S A2020

VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy

Pascale Jablonka

We present detailed chemical abundances for 99 red-giant branch stars in the centre of the Sculptor dwarf spheroidal galaxy, which have been obtained from high-resolution VLT/FLAMES spectroscopy. The abundances of Li, Na, alpha-elements (O, Mg, Si, Ca Ti), ...

EDP Sciences2019

Tracing the formation of the Milky Way through ultra metal-poor stars

Pascale Jablonka, Nicolas Lawrence Etienne Longeard

We use Gaia DR2 astrometric and photometric data, published radial velocities and MESA models to infer distances, orbits, surface gravities, and effective temperatures for all ultra metal-poor stars ([Fe/H] < -4.0 dex) available in the literature. Assuming ...

OXFORD UNIV PRESS2019

The Pristine survey - V. A bright star sample observed with SOPHIE

Pascale Jablonka, Carmela Lardo

With the aim of probing the properties of the bright end of the Pristine survey and its effectiveness in selecting metal-poor stars, we selected a sample of bright candidate metal-poor stars combining Pristine CaHK photometry with APASS gi photometry, befo ...

OXFORD UNIV PRESS2019

The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

Jean-Paul Richard Kneib, Anand Stéphane Raichoor, Timothée Guy Olivier Delubac, Zheng Zheng, Michael James Henry Smith, Yang Gao, Cheng Zhao, Johan Comparat, David Schlegel, John Wilson, Chao Liu, Yuting Wang, Ginevra Favole, Amy Jones, Chen Li, Yuguang Chen, Pierre Laurent, Cheng Li, Guillaume Blanc, Jiayi Sun, Meng Yang, Yu Liang

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in 2014 July. It pursues three core programs: the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2), Mapping Nearby Galaxies at APO (MaNGA), and the Extend ...

Iop Publishing Ltd2017

The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii

Jean-Paul Richard Kneib, Yue Shen

The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of similar to 220,000 optically variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a ...

Iop Publishing Ltd2016

The early days of the Sculptor dwarf spheroidal galaxy

Pascale Jablonka, Pierre North, Yves Revaz

We present the high-resolution spectroscopic study of five -3.9

Edp Sciences S A2015

The Tenth Data Release Of The Sloan Digital Sky Survey: First Spectroscopic Data From The Sdss-Iii Apache Point Observatory Galactic Evolution Experiment

Jean-Paul Richard Kneib, Timothée Guy Olivier Delubac, Zheng Zheng, Johan Comparat, David Schlegel, Ginevra Favole, Yue Shen, Arnaud Borde, Bo Ma

The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Obser ...

Iop Publishing Ltd2014

VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy

Pascale Jablonka

Context. Fornax is one of the most massive dwarf spheroidal galaxies in the Local Group. The Fornax field star population is dominated by intermediate age stars but star formation was going on over almost its entire history. It has been proposed that Forna ...

EDP Sciences2014

Manganese evolution in Omega Centauri: a clue to the cluster formation mechanisms?

We model the evolution of manganese relative to iron in the progenitor system of the globular cluster Omega Centauri by means of a self-consistent chemical evolution model. We use stellar yields that already reproduce the measurements of [Mn/Fe] versus [Fe ...

Blackwell Publishing Ltd, Oxford2011

The CORALIE survey for southern extrasolar planets XVI. Discovery of a planetary system around HD 147018 and of two long period and massive planets orbiting HD 171238 and HD 204313

We report the detection of a double planetary system around HD 140718 as well as the discovery of two long period and massive planets orbiting HD 171238 and HD 204313. Those discoveries were made with the CORALIE Echelle spectrograph mounted on the 1.2-m E ...

2010

Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor, and Sextans

Pascale Jablonka, Pierre North, Martin Tafelmeyer

We present the results of a dedicated search for extremely metal-poor stars in the Fornax, Sculptor, and Sextans dSphs. Five stars were selected from two earlier VLT/Giraffe and HET/HRS surveys and subsequently followed up at high spectroscopic resolution ...

2010