Protoplanetary discs of isolated VLMOs discovered in the IPHAS survey Luisa Valdivielso (IAC) lalalala Collaborators: E. Martín, H. Bouy, E. Solano, J.Drew, R. Greimel, B. Riaz lval@iac.es 10/09/2009

Aims Search young low mass objects on the IPHAS survey Spectral type (SpT) classification with low resolution spectroscopy of the targets Study the chromosferic/accretion activity measuring the Ha equivalent width NaI doublet (818.3nm, 819.5nm) equivalent width as surface gravity indicator Distance estimation and comparison with known SFR’s Spitzer photometry, SED’s & disc properties 2 lval@iac.es L. Valdivielso

Outline Introduction Data selection & observations Results Conclusions & perspectives lval@iac.es L. Valdivielso

Introduction Very low mass objects and brown dwarfs Many young objects show Ha emission due to accretion processes Search in star formation regions such as Chamaeleon, Oph, Orionis, Serpens, Taurus, Trapezium… Broadband optical surveys have missed strong Halpha emitters as they appear bluer than they are lval@iac.es L. Valdivielso

Introduction: IPHAS Survey Observations with WFC (Wide Field Camera) on Isaac Newton Telescope Filters: r’ (6240 Å), i’ (7743 Å) Sloan, Ha (6568 Å) Magnitude limit r’ ~20 1800º2 in the North of the Milky Way: search very low mass objects out of the best known star forming regions lval@iac.es L. Valdivielso

Data: targets selection Cross-match of IPHAS with 2MASS (The Two Micron All Sky Survey) catalogue using Aladin: r’, i’, Ha, J, H, K photometry of the targets Selection criteria for 2MASS sources: a) 0.7<J-H<1.3 discard strong reddened objects and red giants b) 0.5<H-K<1.1 cool photospheres objects and/or infrared excess IPHAS counterparts: a) 1.1<r’-Ha<3.0 b) 16<i’<18.5 c) 1.2<r’-i’<2.2 d) 2.9<i’-J<3.5 red objects lval@iac.es L. Valdivielso

Data: Observations WHT/ISIS : - Dates: 2006 August 1-2 - 35 targets texp : 700-1800s NOT/ALFOSC : Dates: 2006 October 10-14 56 targets texp : 300-2400s 3m-Shane Telescope/KAST: - Dates: 2007 July 2-5 - 25 targets lval@iac.es L. Valdivielso

Results 116 IPHAS targets observed: 48 real candidates according new IPHAS photometry 42 objects show strong Ha emission (success rate > 80%) 12 objects M5.5-M7 30 between M0-M5.5 lval@iac.es L. Valdivielso

Ha vs SpT Barrado y Navascués & Martín (2003) criteria to study the accretion level of the targets. All objects with Ha emission show accretion lval@iac.es L. Valdivielso

NaI doublet measurements NaI doublet equivalent width measurements between 8172Å and 8207Å Upper-Sco Comparison with field M dwarfs & Upper Sco members (5Myr) Later type objects show lower surface gravity lval@iac.es L. Valdivielso

Spectro-photometric distances Baraffe Nextgen models log g=4 ; age 5Myr and 2Myr to compute distances SIMBAD search within 30arcmin 16 of them located near molecular clouds, star formation regions and young open clusters: Serpens, North American Nebula, Cep IV, IC1396, Cygnus Some objects not located to any known young association (free-floating ejected from sfr? member of unknown nearby assoc?) controversy bd formation;; betapictoris…) 11 lval@iac.es L. Valdivielso

Spitzer photometry Search Spitzer data to compute SED’s Data avaliable for 17 objects Nº objects with 3.6-24 µm: 9 12 lval@iac.es L. Valdivielso

Spitzer photometry Search Spitzer data to compute SED’s Data avaliable for 17 objects Nº objects with 3.6-24 µm: 9 Comparison with –Oph members 13 lval@iac.es L. Valdivielso

Preliminary SED analysis Robitaille SED online-fitting tool for first estimations of disc properties (Robitaille et al. 2007) Stellar age ~2.5Myr Stellar mass ~0.14Msun Stellar radius ~1.16Rsun Stellar Temperature ~3063K Disk mass ~1.63e-4Msun i(deg) ~40-50 SpT M6 14 lval@iac.es L. Valdivielso

CONCLUSIONS VO tools are very efficient to search for very low mass objects and brown dwarfs using large databases IPHAS survey to detect new objects using optical wavelengths We spectroscopically detect very low mass objects in different regions studied until now Most of the objects with Ha emission show evidences of accretion processes and very low surface density indicative of youth Spitzer data show infrared excesses due to protoplanetary discs lval@iac.es L. Valdivielso

PERSPECTIVES Extend this study using the new release of IPHAS Originally the goal was complement optical surveys but our study proved to be complementary to mid-IR surveys (SPITZER) as well Study in more detail the properties of the isolated young VLMOs (kinematics, activity, GAIA, HERSCHEL) This study can be perform in particular regions to see how many objects have been missed (Guieu et al 2009) 16 lval@iac.es L. Valdivielso 16