Stellar systems and Populations in our Galaxy G. Micela on behalf of the stellar group Istituto Nazionale di Astrofisica Osservatorio Astronomico di Palermo

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 From (solar) stellar X-ray emission to the study of (young) stellar systems and populations of our Galaxy

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona : Space Missions Skylab (1973): breakthrough, first monitoring of the X-ray corona SMM ( ): flares and fine X-ray spectroscopy Yohkoh ( ): monitoring and imaging, flare evolution, hot corona SoHO ( ): EUV spectroscopy and imaging TRACE ( ): high resolution EUV imaging HINODE ( ): high resolution multiband X-ray imaging and UV spectroscopy

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The solar corona Heating mechanisms of the corona Diagnostics: Temperature, Emission Measure, Spatial and thermal structuring Hinode observation of an active region (Reale et al., 2007, Science) Emission Temperature

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The solar corona: CMEs Strong activity starting from SoHO-UVCS spectra (high energy component ) –modeling HPC MHD

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Sun as a star Goal: synthesis of the integrated Sun in order to simulate stellar observations Synthesis of the Sun in several conditions Solar emission measure distribution integrated in space and averaged in time (Argiroffi et al. in preparation)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Perspectives Reinforcing the Hinode collaboration Modeling Stellar extrapolation Involvement in Solar Orbiter (2015)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The stellar coronae: Nearby field stars The Sun has a quiet corona Optical and ‘X-ray’ CM diagram of nearby stars (data from Schmitt et al & Schmitt 1997)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The role of rotation For a given mass, rotation determines the X-ray luminosity level Pluses: field stars Squares: cluster stars (From Pizzolato et al. 2003)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Emission mechanisms and coronal structures Main tool: the spectrum Emission Measure Temperature Density Chemical abundances AD Leo Chandra/LETG spectrum

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Emission mechanisms and coronal structures Emission Measure reconstruction for several stars: Active stars are hotter than quiet stars (Scelsi et al. 2006)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Emission mechanisms and coronal structures Flares are very common in active and young stars Flare frequency of dM stars in Orion (Caramazza et al. 2007)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Emission mechanisms and coronal structures Variability (flares, rotational modulation, eclipses) may constrain the geometry of emitting structures. Modeling of a flare in Prox Cen (Reale et al. 2007)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 LONG TERM VARIABILITY Identification of the X-ray cycle of the moderately active star HD (Favata et al. in preparation)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Perspectives Continuous monitoring with present instruments Next years Relations with optical activity (CoRoT) Next years Hard X-rays, non-thermal emission (Simbol-X) eV resolution spectra (XEUS) >2018

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 X-ray luminosity evolution X-ray luminosity functions for several clusters of different ages Lx depends on rotation Rotation evolves with age  Lx evolves with age

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 X-ray luminosity evolution o Sun during the cycle ● stars from the Sun in time project of Ribas et al. (2005) ―clusters from previous slide X-ray luminosity and coronal temperature decrease with age during the main sequence lifetime (Micela 2003)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Star Forming Regions X-rays allow the discovery of very young stars without disks Stellar populations (  embedded objects  starburst galaxies) “Unbiased” Initial mass function Study of disk frequency and evolution  angular momentum evolution and formation of planetary systems (  the early Sun) Irradiation in the circumstellar environment (  disk evolution and formation of proto- planetary system)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Star Formation regions:Orion X-rays penetrate very deep in the interstellar medium and are very efficient in identifying embedded young stars COUP Project Orion Nebula Cluster: A laboratory to study the role of high energy radiation during the stellar formation

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Other Large Projects on SFRs 19 XMM/Newton fields pointed on formation sites in Taurus (XEST, PI: Guedel) 7 XMM/Newton fields pointed around ONC (PI: Wolk) 500 ksec XMM/Newton pointing on a core of ρ Oph (DROXO, PI: Sciortino) 450 ksec Chandra on NGC 1893 (PI: Micela)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Membership e mass function in several SFRs Star formation in different physical environments NGC 6530: Chandra observation (60 ksec) (Prisinzano et al. 2005)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Next step: toward the edge of the Galaxy: The Chandra/Spitzer observation of NGC kpc from the Galactic Center. The aim is to detect member stars down to 0.8 Msun The IMF in the outer Galaxy: the influence on the environment ~300 stars with IR excess ~1000 X-ray sources Work in progress!! Caramazza et al. in preparation

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Disk frequency in a massive star forming region: NGC 6611 Age 1-3 Myr Dist. 1750pc 56 stars < B5 (with inhomogeneous distribution) >1000 members (in the red area) ~25% disk Spitzer image at 4.5 μ

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 NGC 6611: disk evaporation induced by nearby massive stars Fraction of disks stars as function of the UV flux emitted from the massive stars in the region: Disks tend to evaporate near massive stars (Guarcello et al. 2007)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 PERSPECTIVES Other environments (Arches...) Old clusters Ground based observations (accretion, lithium, rotation, variability..., XSHOOTER 2009) Hard non-thermal emission (SimbolX )

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The young population in the solar neighborhood Lx decreases of 3 orders of magnitude during the main sequence We observe young stars at much larger distances than old stars => Young stars dominate shallow stellar X-ray samples while old stars dominate deep high latitude stellar X-ray samples. Comparisons with stellar galactic models allow us to derive spatial distributions of stellar populations

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 An intermediate survey: the NEP Rosat All Sky Survey: Comparison with the observations (Micela et al. 2007) A significant excess of yellow stars is present Young population identified through optical follow-up

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Chandra and XMM/Newton contribution The high sensitivity allows us to go beyond the scale heights of the youngest stars We may detect all young and intermediate age stars Stellar content of high-latitude deep X-ray surveys is dominated by old low mass stars

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The comparison with the observations: HDFN (Feigelson et al. 2004) The predicted yellow stars are in excess with respect to the observations !!! The opposite than in shallow and intermediate surveys !!! We are looking at old stars, while the previous surveys were dominated by young stars => something of wrong in old star modeling?

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 PERSPECTIVES X-ray deep observations of old clusters Optical High Resolution Spectroscopy GAIA (2011+) Deep surveys (XEUS) X-ray Wide Field Camera ???

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 The Solar Corona The Stellar Coronae Emission mechanisms and Coronal Structures Coronal Evolution Young stars in Open Clusters and Star Forming Regions Initial Mass Function Young stars in the field Star formation history in the solar neighborhood Interaction with the environment

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Interaction with the environment Pre-main sequence phase - interaction star-disk Main sequence stars – interaction star-planetary atmosphere

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Interaction star-disk Solar-like loops but also very long structures, possibly connecting the star with the circumstellar disk (Favata et al. 2005, Flaccomio et al. 2007) Effects on accretion, disk ionization, chemistry l Normal Stars Pre main sequence stars with disks

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Evidence for interaction with the disks: Fluorescence l Emission of X-ray radiation from photo-ionized cold material in the circumstellar disk Best observable line is the FeI K line at 6.4 keV Mainly detections during flares, some cases during the quiescent phase

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Fluorescence line in X-rays FeI K fluorescent line is a tracer of a strong relation between X-rays and cold material Fluorescence observed with XMM in EL29 a PMS star in ρ Oph (Giardino et al. 2007) From DROXO program

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 X-rays heat significantly planetary atmospheres (Cecchi Pestellini et al. 2006) Planetary Mass loss induced by X-rays at very small orbital distance for different istance and density (Penz et al. 2007) Interaction star-planet 1 M jup 1 M nept

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Interaction star-planet Final planet mass distribution starting from a flat initial mass function (Penz et al. 2007)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Interaction star-planet Final Mass of a hot Neptune orbiting around a dM star at 0.02 AU: the case of G876d (Penz & Micela 2007)

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 PERSPECTIVES X-ray induced fluorescence in IR Modeling of fluorescence Comparison with mass function of unbiased observed samples (CoRoT? Kepler, PLATO) Modeling of EUV-UV contribution

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 RESOURCES staff res. ; postdoc; 3.5 PhD FUNDS (active in 2007): –1.5 UE ToK programs (4 postdoc+2 senior) –1 UE RTN –ASI (data analysis and theory) –PRIN INAF –MIUR Special Program

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 X-ray luminosity evolution Feigelson et al Flaccomio et al Micela et al Casanova et al Randich et al Schmitt 1997 Stern et al Lx depends on rotation Rotation evolves with age  Lx evolves with age

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Next step: toward the edge of the Galaxy NGC 1893, a SFR at 14 kpc from the Galactic Center The aim is to detect member stars down to 0.8 Msun The IMF in the outer Galaxy: the influence on the environment Low density Low radiation field Low metallicity Less supernovae and spiral arms

G. Micela – Stellar Systems and Populations in our Galaxy – Palermo 19/12/2007 Spatial distribution and star formation history in the solar X-ray observations tend to select active and young stars Volume limited Low latitude X-ray surveys High latitude X-ray surveys