Zobrazeno 1 - 10
of 63
pro vyhledávání: '"Roberto Pallavicini"'
Publikováno v:
Astronomy & Astrophysics. 488:167-179
Aims. We performed a detailed membership selection and studied the accretion properties of low-mass stars in the two apparently very similar young (1-10 Myr) clusters sigma Ori and lambda Ori. Methods. We observed 98 and 49 low-mass (0.2-1.0 M_sun) s
Publikováno v:
Astronomy & Astrophysics. 469:163-172
Determinations of beryllium abundance in stars, together with lithium, provide a key tool to investigate the so far poorly understood extra-mixing processes at work in stellar interiors. We measured Be in three open clusters,complementing existing Be
Publikováno v:
The Astrophysical Journal. 659:L41-L44
We measured lithium in a sample of low-mass stars (~0.1-0.3 M☉) of the Orion Nebula cluster. We find evidence for significant Li depletion in four high-probability members, corresponding to nuclear ages between ~15 and 30 Myr. In two cases, there i
Autor:
Paolo Di Marcantonio, Roberto Pallavicini, Stefano Covino, Antonio de Ugarte Postigo, Paolo Conconi, Filippo Maria Zerbi, Rosario Cosentino, A. Zacchei, Paolo Santin, Marco Riva, Paolo Spanò, Vincenzo De Caprio
Publikováno v:
Chinese Journal of Astronomy and Astrophysics. 6:361-364
X-shooter is a spectrograph designed to feed the Cassegrain focus of the VLT. It may cover in a single exposure the spectral range from the UV to the H band with possible extension to the K band. The instrument is constituted by three arms, blue, vis
Publikováno v:
Astronomy & Astrophysics. 462:L23-L26
Context: Knowledge of the age distribution of stars in young clusters and associations is crucial to constrain models of star formation. HR diagrams of different young clusters and associations suggest the presence of age spreads, but the influence o
Publikováno v:
Advances in Space Research. 38:1509-1519
We discuss observations of open clusters and star forming regions obtained with the RGS and EPIC instruments on board XMM- Newton . These observations provide a powerful tool to investigate the temperature structure, emission measure distribution and
Autor:
Roberto Pallavicini, Sofia Randich
Publikováno v:
Astronomische Nachrichten. 325:462-476
We present the highlights of current observational programs in stellar optical spectroscopy carried out with 8-10 m class telescopes as well as with smaller telescopes. Topics discussed include: 1. light elements abundances and their cosmological imp
Publikováno v:
Astronomy & Astrophysics. 421:715-727
We present XMM-Newton observations of the young (~2-5 Myr) cluster around the hot (O9.5V) star sigma Orionis AB, aimed at obtaining a high resolution RGS spectrum of the hot star as well as EPIC imaging data for the whole field. We show that the RGS
Autor:
Roberto Pallavicini
Publikováno v:
Advances in Space Research. 32:885-894
I discuss the scientific reasons why solar astronomers should be interested in other stars and why Solar Physics should be put in the broader context of Stellar Astrophysics. Selected topics include stellar interiors and helioseismology, dynamo actio
Publikováno v:
Advances in Space Research. 32:1143-1148
We present observations of stellar clusters obtained with XMM- Newton as part of the Guaranteed Time program. We have obtained EPIC observations of the open clusters Praesepe, a Per, o Ori and Hyades and of the Taurus-Auriga star-forming region. The