12 results on '"L. M. Howes"'
Search Results
2. Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way
- Author
-
P. Pietrukowicz, Radosław Poleski, Martin Asplund, David Yong, Andrzej Udalski, Michael S. Bessell, Andrew R. Casey, Michał K. Szymański, Jan Skowron, Christopher Owen, Melissa Ness, G. S. Da Costa, L. M. Howes, Stefan Keller, Grzegorz Pietrzyński, David M. Nataf, Karin Lind, Patrick Tisserand, Igor Soszyński, Chiaki Kobayashi, S. Kozlowski, Brian P. Schmidt, Krzysztof Ulaczyk, P. Mróz, and Łukasz Wyrzykowski
- Subjects
Physics ,Multidisciplinary ,COSMIC cancer database ,Spiral galaxy ,Milky Way ,FOS: Physical sciences ,Astronomy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Bulge ,Astrophysics of Galaxies (astro-ph.GA) ,Thick disk ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that the most metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon., Published in Nature on 11/11/15, see http://dx.doi.org/10.1038/nature15747
- Published
- 2015
3. Estimating stellar ages and metallicities from parallaxes and broadband photometry - successes and shortcomings
- Author
-
Thomas Bensby, Lennart Lindegren, Ross P. Church, L. M. Howes, and Sofia Feltzing
- Subjects
Physics ,010308 nuclear & particles physics ,Metallicity ,Milky Way ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy ,Stars ,Photometry (astronomy) ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Galaxy formation and evolution ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Parallax ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Open cluster - Abstract
A deep understanding of the Milky Way galaxy, its formation and evolution requires observations of huge numbers of stars. Stellar photometry, therefore, provides an economical method to obtain intrinsic stellar parameters. With the addition of distance information - deriving reliable ages from photometry is a possibility. We have developed a Bayesian method that generates 2D probability maps of a star's age and metallicity from photometry and parallax using isochrones. Our synthetic tests show that including a near-UV passband enables us to break the degeneracy between a star's age and metallicity for certain evolutionary stages. It is possible to find well-constrained ages and metallicities for turn-off and sub-giant stars with colours including a U band and a parallax with uncertainty less than ~20%. Metallicities alone are possible for the main sequence and giant branch. We find good agreement with the literature when we apply our method to the Gaia benchmark stars, particularly for turn-off and young stars. Further tests on the old open cluster NGC 188, however, reveal significant limitations in the stellar isochrones. The ages derived for the cluster stars vary with evolutionary stage, such that turn-off ages disagree with those on the sub-giant branch, and metallicities vary significantly throughout. Furthermore, the parameters vary appreciably depending on which colour combinations are used in the derivation. We identify the causes of these mismatches and show that improvements are needed in the modelling of giant branch stars and in the creation and calibration of synthetic near-UV photometry. Our results warn against applying isochrone fitting indiscriminately. In particular, the uncertainty on the stellar models should be quantitatively taken into account. Further efforts to improve the models will result in significant advancements in our ability to study the Galaxy., Comment: Accepted for publication in A&A. 22 pages, 19 figures (+ 6 pages of appendix). Abstract abridged for the arXiv
- Published
- 2018
- Full Text
- View/download PDF
4. Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way
- Author
-
Krzysztof Ulaczyk, Daisuke Suzuki, J. M. Pawlak, Igor Soszyński, Masayuki Nagakane, Jennifer A. Johnson, L. M. Howes, A. Wyrzykowski, Jennifer C. Yee, Thomas Bensby, P. J. Tristram, Takahiro Sumi, Jan Skowron, Jorge Melendez, Yuki Hirao, P. Mróz, Aparna Bhattacharya, Andrzej Udalski, Michał K. Szymański, Sara Lucatello, P. Pietrukowicz, Yuichiro Asakura, Radosław Poleski, Naoki Koshimoto, Fumio Abe, Andrew Gould, Andrew McWilliam, S. Kozlowski, Martin Asplund, Ian A. Bond, Sofia Feltzing, David P. Bennett, ITA, USA, GBR, FRA, DEU, and SWE
- Subjects
Physics ,010308 nuclear & particles physics ,Star formation ,Metallicity ,Milky Way ,Galactic Center ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Space and Planetary Science ,Bulge ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Thick disk ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,10. No inequality ,ABUNDÂNCIA ESTELAR ,010303 astronomy & astrophysics ,Red clump ,Astrophysics::Galaxy Astrophysics - Abstract
We present a detailed elemental abundance study of 90 F and G dwarf, turn-off and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y and Ba) have been determined. We find that the Galactic bulge has a wide metallicity distribution with significant peaks at [Fe/H]=-1.09, -0.63, -0.20, +0.12, +0.41. We also find a high fraction of intermediate-age to young stars: at [Fe/H]>0 more than 35 % are younger than 8 Gyr. For [Fe/H], Comment: Accepted for publication in A&A
- Published
- 2017
5. Using the Multi-Object Adaptive Optics demonstrator RAVEN to observe metal-poor stars in and towards the Galactic Centre
- Author
-
Masayuki Akiyama, Shin Oya, Carlos Correia, Martin Asplund, Azadeh Fattahi, Kate Jackson, Yutaka Hayano, Colin Bradley, G. Suzuki, Olivier Lardière, Matthew Shetrone, Hiroshi Terada, D. Andersen, Celia Blain, K. A. Venn, Masen Lamb, K. Youakim, L. M. Howes, Yoshito Ono, Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Proper motion ,stars: abundances ,Infrared ,Metallicity ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,instrumentation: adaptive optics ,01 natural sciences ,010309 optics ,Bulge ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Astrophysics::Galaxy Astrophysics ,Physics ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Astronomy ,Astronomy and Astrophysics ,Galaxy: centre ,Abundance of the chemical elements ,Stars ,globular clusters: individual: M22 ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Globular cluster ,Halo ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,techniques: spectroscopic - Abstract
The chemical abundances for five metal-poor stars in and towards the Galactic bulge have been determined from H-band infrared spectroscopy taken with the RAVEN multi-object adaptive optics science demonstrator and the IRCS spectrograph at the Subaru 8.2-m telescope. Three of these stars are in the Galactic bulge and have metallicities between -2.1 < [Fe/H] < -1.5, and high [alpha/Fe] ~+0.3, typical of Galactic disk and bulge stars in this metallicity range; [Al/Fe] and [N/Fe] are also high, whereas [C/Fe] < +0.3. An examination of their orbits suggests that two of these stars may be confined to the Galactic bulge and one is a halo trespasser, though proper motion values used to calculate orbits are quite uncertain. An additional two stars in the globular cluster M22 show [Fe/H] values consistent to within 1 sigma, although one of these two stars has [Fe/H] = -2.01 +/- 0.09, which is on the low end for this cluster. The [alpha/Fe] and [Ni/Fe] values differ by 2 sigma, with the most metal-poor star showing significantly higher values for these elements. M22 is known to show element abundance variations, consistent with a multi-population scenario (i.e. Marino et al. 2009, 2011; Alves-Brito et al. 2012) though our results cannot discriminate this clearly given our abundance uncertainties. This is the first science demonstration of multi-object adaptive optics with high resolution infrared spectroscopy, and we also discuss the feasibility of this technique for use in the upcoming era of 30-m class telescope facilities., 23 pages, 11 figures, Accepted to MNRAS
- Published
- 2016
6. The EMBLA survey - metal-poor stars in the Galactic bulge
- Author
-
Andrew R. Casey, L. M. Howes, Anna F. Marino, Christopher Owen, Michael S. Bessell, Brian P. Schmidt, David Yong, Anna Frebel, Alan Alves-Brito, Martin Asplund, Gary S. Da Costa, Luca Casagrande, David M. Nataf, Stefan Keller, Austin Hays, P. Tisserand, Karin Lind, Casey, Andrew [0000-0003-0174-0564], Apollo - University of Cambridge Repository, and MIT Kavli Institute for Astrophysics and Space Research
- Subjects
Population II [stars] ,stars: abundances ,Metallicity ,K-type main-sequence star ,bulge [Galaxy] ,FOS: Physical sciences ,Fotometria estelar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Metalicidade ,01 natural sciences ,Galaxy: bulge ,Formacao de galaxias ,evolution [Galaxy] ,Astronomi, astrofysik och kosmologi ,Bulge ,0103 physical sciences ,Galaxy formation and evolution ,Cinemática ,Astronomy, Astrophysics and Cosmology ,Astrophysics::Solar and Stellar Astrophysics ,010306 general physics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Physics ,Galaxy: evolution ,Spiral galaxy ,Astronomy ,Astronomy and Astrophysics ,stars: Population II ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,abundances [stars] ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Bojos de galaxias ,Halo ,Astrophysics::Earth and Planetary Astrophysics - Abstract
Cosmological models predict the oldest stars in the Galaxy should be found closest to the centre of the potential well, in the bulge. The EMBLA Survey successfully searched for these old, metal-poor stars by making use of the distinctive SkyMapper photometric filters to discover candidate metal-poor stars in the bulge. Their metal-poor nature was then confirmed using the AAOmega spectrograph on the AAT. Here we present an abundance analysis of 10 bulge stars with -2.8, Comment: 20 pages, 16 figures. Accepted to Monthly Notices of the Royal Astronomical Society. Online tables can be found at http://www.astro.lu.se/~louise/data
- Published
- 2016
- Full Text
- View/download PDF
7. The Gaia-ESO Survey: the selection function of the Milky Way field stars
- Author
-
Rodolfo Smiljanic, Luca Sbordone, Carmela Lardo, G. Ruchti, A. C. Lanzafame, Sofia Feltzing, Elena Pancino, L. Morbidelli, Sergey E. Koposov, Gerard Gilmore, Georges Kordopatis, Thomas Bensby, Tomaž Zwitter, E. Stonkute, Andrew R. Casey, James R. Lewis, Sofia Randich, Clare Worley, G. G. Sacco, L. M. Howes, Lorenzo Monaco, Laura Magrini, M. T. Costado, Angela Bragaglia, E. Franciosini, A. Hourihane, Paula Jofre, Grazina Tautvaisiene, Andreas Korn, Stonkute E., Koposov S.E., Howes L.M., Feltzing S., Worley C.C., Gilmore G., Ruchti G.R., Kordopatis G., Randich S., Zwitter T., Bensby T., Bragaglia A., Smiljanic R., Costado M.T., Tautvaisiene G., Casey A.R., Korn A.J., Lanzafame A.C., Pancino E., Franciosini E., Hourihane A., Jofre P., Lardo C., Lewis J., Magrini L., Monaco L., Morbidelli L., Sacco G.G., Sbordone L., Koposov, Sergey [0000-0003-2644-135X], Worley, Clare [0000-0001-9310-2898], Gilmore, Gerard [0000-0003-4632-0213], Casey, Andrew [0000-0003-0174-0564], and Apollo - University of Cambridge Repository
- Subjects
Galactic astronomy ,astro-ph.GA ,Milky Way ,Techniques: spectroscopic ,FOS: Physical sciences ,Star count ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Surveys ,01 natural sciences ,evolution [Galaxy] ,surveys ,Bulge ,spectroscopi [Techniques] ,0103 physical sciences ,Galaxy formation and evolution ,Survey ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Selection (genetic algorithm) ,QC ,Astrophysics::Galaxy Astrophysics ,QB ,Physics ,Galaxy: evolution ,Very Large Telescope ,general [Stars] ,010308 nuclear & particles physics ,techniques: spectroscopic, surveys, stars: general, Galaxy: evolution ,Astronomy ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Stars ,13. Climate action ,Space and Planetary Science ,Stars: general ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,astro-ph.IM - Abstract
The Gaia-ESO Survey was designed to target all major Galactic components (i.e., bulge, thin and thick discs, halo and clusters), with the goal of constraining the chemical and dynamical evolution of the Milky Way. This paper presents the methodology and considerations that drive the selection of the targeted, allocated and successfully observed Milky Way field stars. The detailed understanding of the survey construction, specifically the influence of target selection criteria on observed Milky Way field stars is required in order to analyse and interpret the survey data correctly. We present the target selection process for the Milky Way field stars observed with VLT/FLAMES and provide the weights that characterise the survey target selection. The weights can be used to account for the selection effects in the Gaia-ESO Survey data for scientific studies. We provide a couple of simple examples to highlight the necessity of including such information in studies of the stellar populations in the Milky Way., ES, LH, SF, GRR and TB acknowledge support from the project grant ‘The New Milky Way’ from the Knut and Alice Wallenberg Foundation. RS acknowledges support from NCN/Poland through grant 2014/15/B/ST9/03981. AJK acknowledges support by the Swedish National Space Board. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. These data products have been processed by the CASU at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the GaiaESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council. This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell’ Istruzione, dell’ Universita’` e della Ricerca (MIUR) in the form of the grant ‘Premiale VLT 2012’. The results presented here benefit from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. Based on observations obtained as part of the VHS, ESO Program, 179.A-2010 (PI: McMahon). Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science., This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/mnras/stw1011
- Published
- 2016
8. The detailed chemical composition of the terrestrial planet host Kepler-10
- Author
-
Martin Asplund, David Yong, David L. Lambert, Ivan Ramirez, Ian U. Roederer, Thomas Bensby, Fan Liu, Bengt Gustafsson, Jorge Melendez, and L. M. Howes
- Subjects
010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,ESTRELAS ,01 natural sciences ,Astrobiology ,Planet ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Planetary migration ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Secondary atmosphere ,Astronomy and Astrophysics ,Planetary system ,Earth analog ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Terrestrial planet ,Astrophysics::Earth and Planetary Astrophysics ,Primary atmosphere ,Planetary mass ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Chemical abundance studies of the Sun and solar twins have demonstrated that the solar composition of refractory elements is depleted when compared to volatile elements, which could be due to the formation of terrestrial planets. In order to further examine this scenario, we conducted a line-by-line differential chemical abundance analysis of the terrestrial planet host Kepler-10 and fourteen of its stellar twins. Stellar parameters and elemental abundances of Kepler-10 and its stellar twins were obtained with very high precision using a strictly differential analysis of high quality CFHT, HET and Magellan spectra. When compared to the majority of thick disc twins, Kepler-10 shows a depletion in the refractory elements relative to the volatile elements, which could be due to the formation of terrestrial planets in the Kepler-10 system. The average abundance pattern corresponds to ~ 13 Earth masses, while the two known planets in Kepler-10 system have a combined ~ 20 Earth masses. For two of the eight thick disc twins, however, no depletion patterns are found. Although our results demonstrate that several factors (e.g., planet signature, stellar age, stellar birth location and Galactic chemical evolution) could lead to or affect abundance trends with condensation temperature, we find that the trends give further support for the planetary signature hypothesis., 12 pages, 11 figures, accepted for publication in MNRAS
- Published
- 2015
9. The thick disc according to Gaia-ESO
- Author
-
Thomas Bensby and L. M. Howes
- Subjects
Physics ,010308 nuclear & particles physics ,Space and Planetary Science ,0103 physical sciences ,Astronomy ,Astronomy and Astrophysics ,Disc ,010303 astronomy & astrophysics ,01 natural sciences - Abstract
In the era of large spectroscopic surveys, it is vital that selection effects are taken into account when making conclusions about the stellar populations of the Galaxy. Here we use the Galactic disc sample of stars from the Gaia-ESO Survey internal data release 4 (GES iDR4), applying the published selection function to characterise the vertical extent of the chemically defined thick and thin discs.
- Published
- 2017
10. Ultra-deep catalog of X-ray groups in the Extended Chandra Deep Field South
- Author
-
Franz E. Bauer, Viola Allevato, Catherine Heymans, Michael C. Cooper, Andrea Comastri, D. Wilman, Peter Capak, Alexis Finoguenov, Günther Hasinger, B. Luo, V. Mainieri, L. M. Howes, John S. Mulchaey, John D. Silverman, Piero Ranalli, W. N. Brandt, P. Rosati, Christian Schmid, Yongquan Xue, Paola Popesso, F. Ziparo, Masayuki Tanaka, Ami Choi, Paolo Tozzi, Nico Cappelluti, Finoguenov, A., Tanaka, M., Cooper, M., Allevato, V., Cappelluti, N., Choi, A., Heymans, C., Bauer, F. E., Ziparo, F., Ranalli, P., Silverman, J., Brandt, W. N., Xue, Y. Q., Mulchaey, J., Howes, L., Schmid, C., Wilman, D., Comastri, A., Hasinger, G., Mainieri, V., Luo, B., Tozzi, P., Rosati, P., Capak, P., Popesso, P., ITA, and USA
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Large-scale structure of Universe ,Astrophysics::High Energy Astrophysical Phenomena ,Gravitational lensing: weak ,X-rays: galaxies: clusters ,Astronomy and Astrophysics ,Flux ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Luminosity ,NO ,Scaling ,Weak gravitational lensing ,Astrophysics::Galaxy Astrophysics ,Luminosity function (astronomy) ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Astronomy and Astrophysic ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,galaxies: cluster [X-rays] ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Chandra Deep Field South ,Astrophysics - High Energy Astrophysical Phenomena ,weak [Gravitational lensing] ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Ultra-deep observations of ECDF-S with Chandra and XMM-Newton enable a search for extended X-ray emission down to an unprecedented flux of $2\times10^{-16}$ ergs s$^{-1}$ cm$^{-2}$. We present the search for the extended emission on spatial scales of 32$^{\prime\prime}$ in both Chandra and XMM data, covering 0.3 square degrees and model the extended emission on scales of arcminutes. We present a catalog of 46 spectroscopically identified groups, reaching a redshift of 1.6. We show that the statistical properties of ECDF-S, such as logN-logS and X-ray luminosity function are broadly consistent with LCDM, with the exception that dn/dz/d$\Omega$ test reveals that a redshift range of $0.2, Comment: 20 pages, 21 figures, 3 tables, to match the journal version
- Published
- 2015
11. HIP 10725: The First Solar Twin/Analogue Field Blue Straggler
- Author
-
Marcelo Tucci Maia, Maria Lugaro, Matthieu Castro, L. M. Howes, José Dias do Nascimento, Martin Asplund, Jorge Melendez, Marcos A. Faria, Lucas Schirbel, David Yong, Ivan Ramirez, and Amanda I. Karakas
- Subjects
Metallicity ,chemistry.chemical_element ,FOS: Physical sciences ,Context (language use) ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Spectral line ,Blue straggler ,Sun - abundances ,Asymptotic giant branch ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Physics ,Blue stragglers ,ASTROFÍSICA ESTELAR ,Astronomy and Astrophysics ,Stars - abundances ,Radial velocity ,Astrophysics - Solar and Stellar Astrophysics ,chemistry ,Space and Planetary Science ,Globular cluster ,Astrophysics::Earth and Planetary Astrophysics ,Beryllium ,Stars - fundamental parameters - Abstract
[Context]. Blue stragglers are easy to identify in globular clusters, but are much harder to identify in the field. Here we present the serendipitous discovery of one field blue straggler, HIP 10725, that closely matches the Sun in mass and age, but with a metallicity slightly lower than the Sun's. [Methods]. We employ high resolution (R $\sim 10^5$) high S/N (330) VLT/UVES spectra to perform a differential abundance analysis of the solar analogue HIP 10725. Radial velocities obtained by other instruments were also used to check for binarity. We also study its chromospheric activity, age and rotational velocity. [Results]. We find that HIP 10725 is severely depleted in beryllium ([Be/H], A&A in press
- Published
- 2015
- Full Text
- View/download PDF
12. The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge
- Author
-
Alejandra Recio-Blanco, David M. Nataf, Sofia Randich, Karin Lind, A. Hourihane, Carmela Lardo, Sofia Feltzing, G. G. Sacco, Martin Asplund, C. C. Worley, Paula Jofre, Andreas Korn, David Yong, C. Allende Prieto, L. M. Howes, G. S. Da Costa, Enrico Maiorca, Manuela Zoccali, Francesco Damiani, L. Morbidelli, Vanessa Hill, Maria Bergemann, Ulrike Heiter, Andrew R. Casey, Rodolfo Smiljanic, Gerard Gilmore, Stefan Keller, Michael S. Bessell, Dante Minniti, Patrick Tisserand, Laura Magrini, Anna F. Marino, Brian P. Schmidt, Antonella Vallenari, Thomas Masseron, Luca Casagrande, Ettore Flaccomio, P. de Laverny, Elena Pancino, Thomas Bensby, Christopher Owen, M. T. Costado, Howes L.M., Asplund M., Casey A.R., Keller S.C., Yong D., Gilmore G., Lind K., Worley C., Bessell M.S., Casagrande L., Marino A.F., Nataf D.M., Owen C.I., Da Costa G.S., Schmidt B.P., Tisserand P., Randich S., Feltzing S., Vallenari A., Allende Prieto C., Bensby T., Flaccomio E., Korn A.J., Pancino E., Recio-Blanco A., Smiljanic R., Bergemann M., Costado M.T., Damiani F., Heiter U., Hill V., Hourihane A., Jofre P., Lardo C., de Laverny P., Magrini L., Maiorca E., Masseron T., Morbidelli L., Sacco G.G., Minniti D., and Zoccali M.
- Subjects
010504 meteorology & atmospheric sciences ,Evolution ,Metallicity ,K-type main-sequence star ,Milky Way ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Bulge ,0103 physical sciences ,Galaxy formation and evolution ,Population II-Galaxy ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,Physics ,Spiral galaxy ,Bulge-Galaxy ,Astronomy ,Astronomy and Astrophysics ,Stars ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Abundances-star ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Earth and Planetary Astrophysics - Abstract
We present the first results of the EMBLA survey (Extremely Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge, where the oldest stars should now preferentially reside. EMBLA utilises SkyMapper photometry to pre-select metal-poor candidates, which are subsequently confirmed using AAOmega spectroscopy. We describe the discovery and analysis of four bulge giants with -2.72, Comment: 7 pages, 5 figures. Accepted for publication by MNRAS
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.