ESAC RESEARCH: ISO-ASTRO-F Team

Transcription

1 ESAC RESEARCH: ISO-ASTRO-F Team Anibal García-Hernandez, Pedro García-Lario, Rosario Lorente, Alberto Salama, Eva Verdugo ISO Data Centre Science Operations and Data Systems Division Research and Scientific Support Department ESAC, 7 April 2005

2 ESAC Research ISO-ASTRO-F team 5 people (both ISO and ASTRO-F) Total number of refereed publications by members of the group: 101 of which 45 as 1 st,2 nd or 3 rd authors. Refereed publications in the last two years: 12 Other research activities: conferences, several students, paper reviewing, participation as co-investigators in future missions or instruments, participation to proposal review processes. Wide variety of subjects, wealth of different approaches, many international collaborators Page 2

3 Extended sources study with the ISOCAM CVF R. Lorente in collaboration with F. Boulanger (IAS) Mid-IR spectro-imaging observations with the ISOCAM CVF: final reduction and archive, accepted in A&A CAM spectro-imaging products decontaminated from Zodiacal light and Straylight coming from the uniform illumination. corrected uncorrected M31 11 µm The corrections improve essentially the purity of the spectrum and the spatial structure of faint extended emission fields, leading to detection of spectral features weaker that the Zodiacal emission Page 3

4 Point-source photometry in ISOGAL R. Lorente in collaboration with A. Coulais (IAP), K. Okumura (IAP), J. Blommaert (Leuven) CAM point source photometry is affected by non corrected transients effects A newly developed tool (B. Fouks & A. Coulais) is being adapted to apply the correction to a scientific case: ISOGAL SURVEY New transient correction Old transient correction Point source photometry at 7 and 15 µm detected with ISOCAM in the inner Galaxy Page 4

5 The hidden evolution of AGB stars into Planetary Nebulae. I (P. García-Lario) Search for new objects in the short transition phase AGB PN using infrared data (latest results presented as part of last AVO demo) Multi-wavelength analysis of peculiar transition objects (proto-pne and very young PNe) Search for Diffuse Bands in the circumstellar envelopes of C-rich post- AGB stars of intermediate spectral types (investigating the DIB-PAH connection) Page 5

6 The hidden evolution of AGB stars into Planetary Nebulae. I (P. García-Lario) Atlas of optical/near-ir counterparts of extremely reddened OH/IR stars detected with IRAS (massive progenitors?) Discovery of a new class of sources: infrared Planetary Nebulae with OH masers R H J K Determination of 12C/13C isotopic ratios, lithium and s-process element abundances in massive O-rich AGB s in our Galaxy (searching for hot bottom-burning stars), using VLT (2 nights granted in May 2005) Page 6

7 The hidden evolution of AGB stars into Planetary Nebulae. II (P. García-Lario) ISO s view on the AGB to PN transition phase (classification scheme based on the different chemical evolution of stars as a function of their progenitor mass) O-rich low mass stars (>2 solar masses) C-rich intermediate mass stars (2-4 solar masses) O-rich high mass stars (4-8 solar masses) Spitzer observations of Galactic Bulge PNe (10 hours granted to observe ~60 PNe) Page 7

8 12 C/ 13 C ratio as Hot Bottom Burning indicator in heavily obscured O-rich AGB stars Domingo Anibal Garcia-Hernandez (ESA Research Fellowship) Collaborators: P. Garcia-Lario (IDC-ESAC), B. Plez (GRAAL, France), A. Manchado (IAC, Spain) Massive O-rich AGB stars in our Galaxy go through the Hot Bottom Burning phase (indicated by a Lithium overabundance) but they usually are obscured by their thick circumstellar shells in the optical! their HBB status can be studied by measuring the 12 C/ 13 C ratio from near-ir spectroscopy (H and K bands) Page 8

9 Novae & symbiotic stars A. Salama (in collaboration with A. Evans et al.) Exploitation of ISO data Extensive ISO SWS/LWS database on novae and symbiotics Quasi-simultaneous ground based observations in visible, IR, radio To determine: elemental abundances, masses and physical conditions (density, temperature, velocity) of the ejected material The long-term evolution and composition of dust in dusty novae and symbiotics the physical state of the stellar remnant Involvement in two Spitzer programmes Cas 95, Evans et al (2003) Cru 96, Lyke et al (2003) Page 9

10 Magnetic fields in massive stars E. Verdugo (in collaboration with H. Henrichs & R. Schnerr (Amsterdam), C. Neiner (ESTEC/Meudon), A. Talavera (ESAC) and A.I. Gómez de Castro (UCM)) Many OB stars and A supergiants are suspected to have weak surface magnetic fields on several grounds. The widely observed corotating wind structures are thought to be anchored at the surface of the star, presumably coinciding with magnetic footpoints. Typical wind variability in O (Si IV), early B (CIV) and A-supergiant (Hα) stars Page 10

11 Magnetic fields in massive stars E. Verdugo Discovery of a weak magnetic field in the early B star β Cep (B1 IVe) with the MUSICOS polarimeter at TBL Magnetic data as a function of the UV phase => variable magnetic field with a maximum longitudinal component of Bmax ~ 100 G ± 10 G The phase of minima of the stellar wind absorption (maximum emission; deepest minimum in the EW of CIV line) coincides with the extremes of the magnetic field, and the maximum wind absorption coincides with field strength zero. References: Detection of a weak magnetic field in the pulsating Be star β Cep H. Henrichs et al., 2000 in Magnetic Fields of Chemically Peculiar and Related Stars, Eds.: Yu.V. Glagolevskij, I.I and Romanyuk, p The magnetic field of β Cep a key system towards understanding the Be phenomenon? H. Henrichs et al., A&A, in preparation Possible detection in ν Eri (B2 III). R. Schnerr, E. Verdugo and H. Henrichs, A&A, in preparation No detection yet in O stars and A-supergiants Current results reported in many workshops and conferences Future work: Continuus spectropolarimetric observations of OB and A-supergiant stars: MUSICOS polarimeter at TBL (Pic du Midi, France) SARG polarimeter at TNG (La Palma) Page 11

12 Stellar Physics: Magnetic cycles in cool stars R. Lorente & B. Montesinos (LAEFF) A 2-dim dynamo model has been developed: To reproduce the solar magnetic cycle with its main observed characteristics: Magnetic intensity δ between toroidal and poloidal field To apply it to observed cool stars cycles to predict: Cycle duration Cycles Duration Slow rotators Rapid rotators Hot stars Cold stars Magnetic Intensity related to maximum stable magnetic field in the stellar interior Predicting Magnetic Cycles in Late-Type Stars, to be submitted to ApJ Conference: Cool stars, stellar systems and the Sun, Hamburg, July 2004 A 3-dim magnetic model will be developed to predict temporal evolution of surface spots distribution (butterfly diagrams) Page 12

13 Accretion disks and jets in T-Tauri stars A.I. Gómez de Castro & E. Verdugo IUE observations + observing run with the HST/STIS between September 2000 and April High resolution profiles of the Si III{1883,1892} and C III{1907,1909} lines were obtained for 6 TTSs The profiles are very complex displaying several components. DE Tau: The Si III] profile is symmetric. The C III] profile is broader due to the excess of blueshifted emission at the jet velocity. The lines ratio suggests a density of ~10 8 cm -3 for the jet. RY Tau: The Si III] profile is very broad and asymmetric. This asymmetric component is readily identified in the C III] profile. A.I. Gómez de Castro & Science E. Verdugo, Operations 2001, ApJ, 548, & Data 976. Systems Division Future work: spectra of 4 of the stars still being analyzed. T Tau: The Si III] profile is resolved into two components: the central component associated with the stellar atmosphere and the blueshifted one associated with the jet. RW Aur: The Si III] profile is symmetric and unusually broad. The C III] line is resolved into three components: The central one caused by the stellar atmosphere and two at high velocities produced in a rotating belt alike the detected in other sources of bipolar outflows. A.I. Gómez de Castro & E. Verdugo, 2003, ApJ, 597, 443. A.I. Gómez de Castro & E. Verdugo, 2004, Ap&SS, 2004, 292, 691. RU Lup: The Si III] profile is slightly asymmetric because of the presence of a blueshifted component related to the jet. The C III] emission is very weak pointing out the very high density of the stellar atmosphere. AK Sco: The Si III] and C III] profiles are broad. The similar strength of both lines points out that the electron density is very small compared with typical atmospheric values. Page 13

14 Discoveries on Titan by Infrared Space Observatory (ISO) A. Coustenis, A. Salama, B. Schulz, E. Lellouch, Th. Encrenaz, S. Ott, M. Kessler, Th. De Graauw, the ISO Titan Team Water vapour (Coustenis et al., 1998) Detected also in the giant planets Implies influx of water of a few 10 6 cm -2 s -1 HC 3 N And Benzene (Coustenis et al., 2003) Vertical distributions of C 6 H 6, HC 3 N, C 2 H 2, HC 3 N, C 2 H 6, CO 2 CH 3 D, CH 4 C 6 H 6 D/H ratio from CH 3 D, CH 4 Upper limits of allene, acetonitrile, propionitrile, and other more complex gases First surface albedo spectrum in the 3 micron methane window (Coustenis et al., 2005) Compatible with water ice and additional Research components & Scientific Support Department Surface methane abundance on the order of or less than 3%. Page 14