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PRODID:-//Osservatorio Astronomico di Roma - ECPv6.15.20//NONSGML v1.0//EN
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METHOD:PUBLISH
X-ORIGINAL-URL:https://www.oa-roma.inaf.it
X-WR-CALDESC:Eventi per Osservatorio Astronomico di Roma
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DTSTART:20160327T010000
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DTSTART:20161030T010000
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DTSTART:20170326T010000
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DTSTART:20171029T010000
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DTSTART:20180325T010000
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DTSTART:20181028T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170502T114500
DTEND;TZID=Europe/Rome:20170502T124500
DTSTAMP:20260425T140151
CREATED:20160915T091415Z
LAST-MODIFIED:20160915T091415Z
UID:4689-1493725500-1493729100@www.oa-roma.inaf.it
SUMMARY:The chemical composition of globular clusters throughout the Local Group
DESCRIPTION:I will discuss results from our recent work on the detailed chemistry of GCs in Local Group galaxies. This work is based on a combination of integrated-light spectroscopy at high resolution and resolved imaging with HST in colour combinations that are sensitive to light-element abundance variations. Through the resolved imaging studies\, it is now clear that the abundance anomalies that are the hallmark of multiple stellar populations are not restricted to old GCs\, but are also found in LMC/SMC clusters as young as 2 Gyrs. This rules out formation mechanisms that were unique to the high redshift Universe. More generally\, we find that GCs in dwarfs are\, on average\, more metal-poor than those in larger galaxies\, although no clusters more metal-poor than [Fe/H]\approx-2.5 have been found so far. Overall\, a large fraction of the most metal-poor stars in dwarf galaxies tend to belong to GCs. This has important implications for scenarios that invoke heavy cluster mass loss to account for the large fractions of enriched “second-generation” stars in GCs\, as well as for globular cluster disruption and its contribution to the field star populations in halos in general.
URL:https://www.oa-roma.inaf.it/event/seminario-7-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170502T114500
DTEND;TZID=Europe/Rome:20170502T124500
DTSTAMP:20260425T140151
CREATED:20160915T091415Z
LAST-MODIFIED:20160915T091415Z
UID:1547-1493725500-1493729100@www.oa-roma.inaf.it
SUMMARY:The chemical composition of globular clusters throughout the Local Group
DESCRIPTION:I will discuss results from our recent work on the detailed chemistry of GCs in Local Group galaxies. This work is based on a combination of integrated-light spectroscopy at high resolution and resolved imaging with HST in colour combinations that are sensitive to light-element abundance variations. Through the resolved imaging studies\, it is now clear that the abundance anomalies that are the hallmark of multiple stellar populations are not restricted to old GCs\, but are also found in LMC/SMC clusters as young as 2 Gyrs. This rules out formation mechanisms that were unique to the high redshift Universe. More generally\, we find that GCs in dwarfs are\, on average\, more metal-poor than those in larger galaxies\, although no clusters more metal-poor than [Fe/H]\approx-2.5 have been found so far. Overall\, a large fraction of the most metal-poor stars in dwarf galaxies tend to belong to GCs. This has important implications for scenarios that invoke heavy cluster mass loss to account for the large fractions of enriched “second-generation” stars in GCs\, as well as for globular cluster disruption and its contribution to the field star populations in halos in general.
URL:https://www.oa-roma.inaf.it/event/seminario-7/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170508T114500
DTEND;TZID=Europe/Rome:20170508T124500
DTSTAMP:20260425T140151
CREATED:20170101T102934Z
LAST-MODIFIED:20170101T102934Z
UID:4702-1494243900-1494247500@www.oa-roma.inaf.it
SUMMARY:A review in mixed-chemistry of low-mass evolved stars
DESCRIPTION:During the late stages of their evolution\, Sun-like stars bring the products of nuclear burning to the surface. There is a chemical dichotomy between oxygen-rich and carbon-rich evolved stars\, however\, in the last three decades\, a few stars have been shown to display both carbon-and oxygen-rich material in their circumstellar envelopes. These phenomena is seen in both Galactic Disk and Bulge planetary nebulae. For the Galactic Disk objects the mixed chemistry phenomenon is best explained through a recent dredge-up of carbon produced by nucleosynthesis inside the star during the Asymptotic Giant Branch that changed the surface chemistry of the star. On the contrary\, the mixed chemistry phenomenon occurring in the Galactic Bulge planetary nebulae is best explained through hydrocarbon chemistry in an ultraviolet (UV)-irradiated\, dense torus.
URL:https://www.oa-roma.inaf.it/event/seminario-lizette-guzman-ramirez-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170508T114500
DTEND;TZID=Europe/Rome:20170508T124500
DTSTAMP:20260425T140151
CREATED:20170101T102934Z
LAST-MODIFIED:20170101T102934Z
UID:2249-1494243900-1494247500@www.oa-roma.inaf.it
SUMMARY:A review in mixed-chemistry of low-mass evolved stars
DESCRIPTION:During the late stages of their evolution\, Sun-like stars bring the products of nuclear burning to the surface. There is a chemical dichotomy between oxygen-rich and carbon-rich evolved stars\, however\, in the last three decades\, a few stars have been shown to display both carbon-and oxygen-rich material in their circumstellar envelopes. These phenomena is seen in both Galactic Disk and Bulge planetary nebulae. For the Galactic Disk objects the mixed chemistry phenomenon is best explained through a recent dredge-up of carbon produced by nucleosynthesis inside the star during the Asymptotic Giant Branch that changed the surface chemistry of the star. On the contrary\, the mixed chemistry phenomenon occurring in the Galactic Bulge planetary nebulae is best explained through hydrocarbon chemistry in an ultraviolet (UV)-irradiated\, dense torus.
URL:https://www.oa-roma.inaf.it/event/seminario-lizette-guzman-ramirez/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170516T114500
DTEND;TZID=Europe/Rome:20170516T124500
DTSTAMP:20260425T140151
CREATED:20170505T121806Z
LAST-MODIFIED:20170505T121806Z
UID:2931-1494935100-1494938700@www.oa-roma.inaf.it
SUMMARY:Orbital evolution of AMXP in the context of non-conservative mass transfer
DESCRIPTION:In this seminar I present:\n1) a detailed discussion of the orbital evolution of SAXJ1808.4-3658 and other Accreting Millisecond Pulsar in the context of the Applegate & Shaham mechanism.\n2) a discussion of the orbital evolution of AMXP in the context of\nnon-conservative accretion models\, and in particular of the so called\nRadio-Ejection hypothesis (Burderi et al. 2001\, ApJ; Di Salvo et al. 2008\, ApJ).\nIn particular I will apply these models to the orbital evolution of\nthe accreting millisecond pulsar SAXJ1808.
URL:https://www.oa-roma.inaf.it/event/orbital-evolution-of-amxp-in-the-context-of-non-conservative-mass-transfer/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170516T114500
DTEND;TZID=Europe/Rome:20170516T124500
DTSTAMP:20260425T140151
CREATED:20170505T121806Z
LAST-MODIFIED:20170505T121806Z
UID:4711-1494935100-1494938700@www.oa-roma.inaf.it
SUMMARY:Orbital evolution of AMXP in the context of non-conservative mass transfer
DESCRIPTION:In this seminar I present:\n1) a detailed discussion of the orbital evolution of SAXJ1808.4-3658 and other Accreting Millisecond Pulsar in the context of the Applegate & Shaham mechanism.\n2) a discussion of the orbital evolution of AMXP in the context of\nnon-conservative accretion models\, and in particular of the so called\nRadio-Ejection hypothesis (Burderi et al. 2001\, ApJ; Di Salvo et al. 2008\, ApJ).\nIn particular I will apply these models to the orbital evolution of\nthe accreting millisecond pulsar SAXJ1808.
URL:https://www.oa-roma.inaf.it/event/orbital-evolution-of-amxp-in-the-context-of-non-conservative-mass-transfer-2/
LOCATION:Aula Gratton
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170523T114500
DTEND;TZID=Europe/Rome:20170523T124500
DTSTAMP:20260425T140151
CREATED:20170208T081112Z
LAST-MODIFIED:20170208T081112Z
UID:2440-1495539900-1495543500@www.oa-roma.inaf.it
SUMMARY:What process(es) produced  barium in the Early Universe?
DESCRIPTION:In the last years our group has found that many chemical anomalies\nobserved in very metal-poor halo stars in the light elements suggest\nthat the first stellar generations were fast rotators\n(spinstars). Recently\, theoretical computations have found that\nspinstars can also play a role in the chemical enrichment of neutron\ncapture elements providing a early contribution of s-process. By means\nof a stochastic chemical evolution model\, it is possible to identify\nthe spinstars s-process contribution as the missing component\nresponsible for the spread in the ratio between light (Sr) to heavy\n(Ba) neutron capture elements. A specific distribution is predicted\nfor the isotopic ratio of Ba in halo stars and this imprint could be\nthe smoking gun of the role played by spinstars in the spread of\n[Sr/Ba] ratio.  In this context\, regarding the still unknown origin of\nthe complementary r-process component\, I present new constraints on\nthe rate and time scales of r-process events\, based on the recent\ndiscovery of the r-process rich stars in the ultra faint galaxy\nReticulum 2.
URL:https://www.oa-roma.inaf.it/event/talk-by-gabriele-cescutti/
LOCATION:RM
CATEGORIES:Seminari
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Rome:20170523T114500
DTEND;TZID=Europe/Rome:20170523T124500
DTSTAMP:20260425T140151
CREATED:20170208T081112Z
LAST-MODIFIED:20170208T081112Z
UID:4706-1495539900-1495543500@www.oa-roma.inaf.it
SUMMARY:What process(es) produced  barium in the Early Universe?
DESCRIPTION:In the last years our group has found that many chemical anomalies\nobserved in very metal-poor halo stars in the light elements suggest\nthat the first stellar generations were fast rotators\n(spinstars). Recently\, theoretical computations have found that\nspinstars can also play a role in the chemical enrichment of neutron\ncapture elements providing a early contribution of s-process. By means\nof a stochastic chemical evolution model\, it is possible to identify\nthe spinstars s-process contribution as the missing component\nresponsible for the spread in the ratio between light (Sr) to heavy\n(Ba) neutron capture elements. A specific distribution is predicted\nfor the isotopic ratio of Ba in halo stars and this imprint could be\nthe smoking gun of the role played by spinstars in the spread of\n[Sr/Ba] ratio.  In this context\, regarding the still unknown origin of\nthe complementary r-process component\, I present new constraints on\nthe rate and time scales of r-process events\, based on the recent\ndiscovery of the r-process rich stars in the ultra faint galaxy\nReticulum 2.
URL:https://www.oa-roma.inaf.it/event/talk-by-gabriele-cescutti-2/
LOCATION:RM
CATEGORIES:Seminari
END:VEVENT
END:VCALENDAR