Showing papers by "Philip W. Lucas published in 2014"
University of California, Berkeley1, University of Hawaii2, Ames Research Center3, Harvard University4, California Institute of Technology5, Yale University6, Pennsylvania State University7, Aarhus University8, National Center for Atmospheric Research9, University of Birmingham10, University of Copenhagen11, Massachusetts Institute of Technology12, University of Washington13, University of Texas at Austin14, Las Cumbres Observatory Global Telescope Network15, Northwestern University16, Planetary Science Institute17, University of Chicago18, University of California, Santa Cruz19, University of Hertfordshire20, San Diego State University21, University of Sydney22, University of Amsterdam23, Max Planck Society24, Iowa State University25, Space Science Institute26, Carnegie Institution for Science27, Lawrence Hall of Science28, Villanova University29, University of Notre Dame30, Institut d'Astrophysique de Paris31, Centre national de la recherche scientifique32, Aix-Marseille University33, University of Porto34, Spanish National Research Council35
TL;DR: In this paper, the masses, sizes, and orbits of the planets orbiting 22 Kepler stars were reported, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars.
Abstract: We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm(-3), suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than similar to 2 R-circle plus. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).
565 citations
TL;DR: In this article, the masses, sizes, and orbits of the planets orbiting 22 Kepler stars were reported, including 49 candidates detected through transits and 7 revealed by precise Doppler measurements of the host stars.
Abstract: We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities for all of the transiting planets (41 of 42 have a false-positive probability under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than 3X the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify 6 planets with densities above 5 g/cc, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than ~2 R_earth. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).
528 citations
University of California, Berkeley1, University of Hawaii2, Ames Research Center3, Harvard University4, California Institute of Technology5, Yale University6, Pennsylvania State University7, Aarhus University8, National Center for Atmospheric Research9, University of Birmingham10, University of Copenhagen11, Massachusetts Institute of Technology12, University of Washington13, University of Texas at Austin14, Las Cumbres Observatory Global Telescope Network15, Northwestern University16, Planetary Science Institute17, University of Chicago18, University of California, Santa Cruz19, University of Hertfordshire20, San Diego State University21, University of Sydney22, University of Amsterdam23, Max Planck Society24, Iowa State University25, Space Science Institute26, Carnegie Institution for Science27, Lawrence Hall of Science28, Villanova University29, University of Notre Dame30, Centre national de la recherche scientifique31, Institut d'Astrophysique de Paris32, Aix-Marseille University33, University of Porto34, Spanish National Research Council35
TL;DR: The National Aeronautics and Space Administration (NEASA) participated in the Kepler Participating Scientist Program (KSP) NNX12AC76G as discussed by the authors.
Abstract: National Aeronautics and Space Administration (Kepler Participating Scientist Program NNX12AC76G)
313 citations
Millennium Institute1, Valparaiso University2, Aryabhatta Research Institute of Observational Sciences3, University of Alicante4, Pontifical Catholic University of Chile5, Universidade Federal do Rio Grande do Sul6, University of Concepción7, University of Cincinnati8, European Southern Observatory9, University of Hertfordshire10, Saint Mary's University11, Catholic University of the North12, Universidade Federal de Sergipe13
TL;DR: The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the GalaxyAims The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge.
Abstract: Context VISTA Variables in the Via Lactea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA) The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the GalaxyAims The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulgeMethods Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JH K S color images to select new cluster candidates on the basis of apparent overdensities DR1, DR2, CASU, and point spread function photometry of 10 × 10 arcmin fields centered on each candidate cluster were used to construct color–magnitude and color–color diagrams Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their natureResults We report the discovery of 58 new infrared cluster candidates Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters
68 citations
Valparaiso University1, Millennium Institute2, Aryabhatta Research Institute of Observational Sciences3, University of Alicante4, Pontifical Catholic University of Chile5, Universidade Federal do Rio Grande do Sul6, University of Concepción7, University of Cincinnati8, European Southern Observatory9, University of Hertfordshire10, Saint Mary's University11, Catholic University of the North12, Universidade Federal de Sergipe13
TL;DR: The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy as mentioned in this paper.
Abstract: VISTA Variables in the V\'ia L\'actea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy.
The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge. Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JHKs color images to select new cluster candidates on the basis of apparent overdensities. DR1, DR2, CASU, and PSF photometry of 10x10 arcmin fields centered on each candidate cluster were used to construct color-magnitude and color-color diagrams. Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their nature.
We report the discovery of 58 new infrared cluster candidates. Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters.
41 citations
TL;DR: In this article, the authors investigated the color-magnitude diagram of the Milky Way bulge, which shows a red giant clump of core He burning stars that is split into two color components, with a mean color difference of (Z − K s ) = 0.55 mag.
Abstract: The new generation of IR surveys are revealing and quantifying Galactic features that provide an improved 3D interpretation of our own Galaxy. We present an analysis of the global distribution of dust clouds in the bulge using the near-IR photometry of 157 million stars from the VVV survey. We investigate the color−magnitude diagram of the Milky Way bulge, which shows a red giant clump of core He burning stars that is split into two color components, with a mean color difference of (Z − K s ) = 0.55 mag that is equivalent to A V = 2.0 mag. We conclude that there is an optically thick dust lane at intermediate latitudes above and below the plane that stretches across several square degrees from l = −10° to l = +10°. We call this feature the great dark lane. Although its exact distance is uncertain, it is located in front of the bulge. The evidence for a large-scale great dark lane within the Galactic bulge is important for constraining models of the barred Milky Way bulge and for comparing our galaxy with external barred galaxies in which these types of features are prominent. We discuss two other potential implications of the great dark lane for microlensing and bulge stellar populations studies.
19 citations
TL;DR: In this article, the authors present an analysis of the global distribution of dust clouds in the Milky Way bulge using the near-IR photometry of 157 million stars from the VVV Survey.
Abstract: The new generation of IR surveys are revealing and quantifying Galactic features, providing an improved 3-D interpretation of our own Galaxy. We present an analysis of the global distribution of dust clouds in the bulge using the near-IR photometry of 157 million stars from the VVV Survey. We investigate the color magnitude diagram of the Milky Way bulge which shows a red giant clump of core He burning stars that is split in two color components, with a mean color difference of (Z-Ks)=0.55 magnitudes equivalent to A_V=2.0 magnitudes. We conclude that there is an optically thick dust lane at intermediate latitudes above and below the plane, that runs across several square degrees from l=-10 deg to l=+10 deg. We call this feature the "Great Dark Lane". Although its exact distance is uncertain, it is located in front of the bulge. The evidence for a large-scale great dark lane within the Galactic bulge is important in order to constrain models of the barred Milky Way bulge and to compare our galaxy with external barred galaxies, where these kinds of features are prominent. We discuss two other potential implications of the presence of the Great Dark Lane for microlensing and bulge stellar populations studies.
12 citations
Journal Article•
TL;DR: Hempel et al. as mentioned in this paper described the Milky Way Millennium Nucleus as the "world's largest and most active galaxy" and showed that it is composed of millions of stars.
Abstract: Fil: Hempel, Maren. Pontificia Universidad Catolica de Chile; Chile. The Milky Way Millennium Nucleus; Chile
5 citations
TL;DR: In this article, the authors present the results of a H− and K−band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster.
Abstract: We present the results of a H− and K−band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2-m Subaru telescope and ISLE on the 1.88-m telescope of Okayama Astronomical Observatory. Eight out of twelve spectra show strong water absorptions and we confirm that their effective temperatures are ≤ 3000 K (spectral type ≥ M6) from a chi-square fit to synthetic spectra. We plot our sources on an HR diagram overlaid with theoretical isochrones of low-mass objects and identify three new young brown dwarf candidates. One of the three new candidates is a cool object near the brown dwarf and planetary mass boundary. Based on our observations and those of previous studies, we determine the stellar (0.08< M/M⊙ < 1) to substellar (0.03< M/M⊙ < 0.08) mass number ratio in the outer regions of the Orion nebular cluster to be 3.5± 0.8. In combination with the number ratio reported for the central region (3.3+0.8 −0.7), this result suggests the number ratio does not simply change with the distance from the center of the Orion nebular cluster.
3 citations
Posted Content•
TL;DR: The VISTA Variables in the VIA L\'actea (VVV) survey is one of the public ESO surveys, and is now in its 4th year of observing as discussed by the authors.
Abstract: The VISTA Variables in the V\'ia L\'actea (VVV) survey is one of six public ESO surveys, and is now in its 4th year of observing. Although far from being complete, the VVV survey has already delivered many results, some directly connected to the intended science goals (detection of variables stars, microlensing events, new star clusters), others concerning more exotic objects, e.g. novae. Now, at the end of the fourth observing period, and comprising roughly 50% of the proposed observations, the actual status of the survey, as well some of the results based on the VVV data, are presented.