bluuebunny/crossref_metadata_2025 huggingface dataset:
Household food security is associated with growth of infants and young children in rural Bangladesh
Authors: Saha Kuntal K , Frongillo Edward A , Alam Dewan S , Arifeen Shams E , Persson Lars Å , Rasmussen Kathleen M
Published: February 2009

Objective

Despite a strong relationship between household food security and the health and nutritional status of adults and older children, the association of household food security with the growth of infants and young children has not been adequately studied, particularly in developing countries. We examined the association between household food security and subsequent growth of infants and young children in rural Bangladesh.

Design

We followed 1343 children from birth to 24 months of age who were born in the Maternal and Infant Nutrition Intervention in Matlab (MINIMat) study in rural Bangladesh. A food security scale was created from data collected on household food security from the mothers during pregnancy. Data on weight and length were collected monthly in the first year and quarterly in the second year of life. Anthropometric indices were calculated relative to the 2006 WHO child growth standards. Growth trajectories were modelled using multilevel models for change controlling for possible confounders.

Results

Household food security was associated (P < 0·05) with greater subsequent weight and length gain in this cohort. Attained weight, length and anthropometric indices from birth to 24 months were higher (P < 0·001) among those who were in food-secure households. Proportions of underweight and stunting were significantly (P < 0·05) lower in food-secure households.

Conclusions

These results suggest that household food security is a determinant of child growth in rural Bangladesh, and that it may be necessary to ensure food security of these poor rural households to prevent highly prevalent undernutrition in this population and in similar settings elsewhere in the world.
Height differences and the associations between food insecurity, percentage body fat and BMI among men and women
Authors: Tayie Francis A , Zizza Claire A
Published: February 2009

Objective

The present study examined the associations between adult food insecurity (FI) and percentage body fat (%BF) and BMI, stratified by height (HT).

Design, setting and subjects

%BF, HT and BMI of 2117 men and 1909 women in the National Health and Nutrition Examination Survey 1999–2002 were analysed in relation to adult food security status using multiple regression procedures.

Results

Compared with the fully food-secure, men’s %BF, BMI and HT were lower as FI intensified. Marginal food security among women was associated with 1·3 cm shorter HT, P = 0·016. Marginal food security among women who were below median HT was associated with about 2·0 kg/m2 higher BMI, P = 0·042. %BF was not associated with FI among women.

Conclusions

FI is associated with shorter HT and lower %BF and BMI in men. Women’s HT should be considered in the reported associations between FI and higher BMI.
Vitamin D deficiency in early childhood: prevalent in the sunny South Pacific
Authors: Grant Cameron C , Wall Clare R , Crengle Sue , Scragg Robert
Published: February 2009

Objective

To estimate the prevalence of and risk factors for vitamin D deficiency in young urban children in Auckland, New Zealand, where there is no routine vitamin D supplementation.

Design

A random sample of urban children. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D <27·5 nmol/l (<11 ng/ml). Logistic regression analysis was used to calculate odds ratios and, from these, relative risks (RR) and 95 % confidence intervals were estimated.

Setting

Auckland, New Zealand (36°52′S), where the daily vitamin D production by solar irradiation varies between summer and winter at least 10-fold.

Subjects

Children aged 6 to 23 months enrolled from 1999 to 2002.

Results

Vitamin D deficiency was present in forty-six of 353 (10 %; 95 % CI 7, 13 %). In a multivariate model there was an increased risk of vitamin D deficiency associated with measurement in winter or spring (RR = 7·24, 95 % CI 1·55, 23·58), Pacific ethnicity (RR = 7·60, 95 % CI 1·80, 20·11), not receiving any infant or follow-on formula (RR = 5·69, 95 % CI 2·66, 10·16), not currently receiving vitamin supplements (RR = 5·32, 95 % CI 2·04, 11·85) and living in a more crowded household (RR = 2·36, 95 % CI 1·04, 4·88).

Conclusions

Vitamin D deficiency is prevalent in early childhood in New Zealand. Prevalence varies with season and ethnicity. Dietary factors are important determinants of vitamin D status in this age group. Vitamin D supplementation should be considered as part of New Zealand’s child health policy.
Screen time and adiposity in adolescents in Mexico
Authors: Lajous Martín , Chavarro Jorge , Peterson Karen E , Hernández-Prado Bernardo , Cruz-Valdéz Aurelio , Hernández-Ávila Mauricio , Lazcano-Ponce Eduardo
Published: February 2009

Objective

To assess the association of time spent viewing television, videos and video games with measures of fat mass (BMI) and distribution (triceps and subscapular skinfold thicknesses (TSF, SSF)).

Design

Cross-sectional validated survey, self-administered to students to assess screen time (television, videos and video games) and lifestyle variables. Trained personnel obtained anthropometry. The association of screen time with fat mass and distribution, stratified by sex, was modelled with multivariable linear regression analysis, adjusting for potential confounders and correlation of observations within schools.

Setting

State of Morelos, Mexico.

Subjects

Males (n3519) and females (n5613) aged 11 to 18 years attending urban and rural schools in Morelos.

Results

In males, screen time of >5 h/d compared with <2 h/d was significantly associated with a 0·13 (95 % CI 0·04, 0·23) higher BMIZ-score, 0·73 mm (95 % CI 0·24, 1·22) higher SSF and 1·08 mm (95 % CI 0·36, 1·81) higher TSF. The positive association of screen time with SSF was strongest in males aged 11–12 years. Sexual maturity appeared to modify the association in females; a positive association between screen time and SSF was observed in those who had not undergone menarche (Pfor trend = 0·04) but not among sexually mature females (Pfor trend = 0·75).

Conclusion

Screen time is associated with fat mass and distribution among adolescent males in Mexico. Maturational tempo appears to affect the relationship of screen time with adiposity in boys and girls. Findings suggest that obesity preventive interventions in the Mexican context should explore strategies to reduce screen time among youths in early adolescence.
Search for Transiting Exoplanets with HATNet
Authors: Bakos G. Á. , Noyes R. W. , Kovács G. , Latham D. W. , Torres G. , Sasselov D. , Pál A. , Sipőcz B. , Kovács Gábor
Published: February 2009

HATNet is a network of six identical, fully automated wide field telescopes, four of which are located in Arizona, and two at Hawaii. The purpose of the network is to search for transiting extrasolar planets around relatively bright stars (8 <I< 12). The longitudinal coverage of 3.5 hours greatly enhances transit detection efficiency. HATNet has been operational since 2004, and has taken more than 1/2 million science frames at 5-min integrations, covering about 7% of the sky. Photometric precision reaches 3mmag rms at 5.5 min cadence atI≈ 8, and is 1% atI≈ 11.3. Hundreds of transitcandidateshave been detected in the data, and have been subject to vigorous follow-up by various 1m-class facilities, both spectroscopy and follow-up photometry. A fraction of the candidates that have survived these steps as not being false alarms have been observed by high resolution and precision spectrographs (primarily Keck/HIRES), to confirm their planetary nature and characterize their properties. So far nine transiting planets have been reported, making HATNet a very successful survey.
Transits against Fainter Stars: The Power of Image Deconvolution
Authors: Sackett Penny D. , Gillon Michaël , Bayliss Daniel D. R. , Weldrake David T. F. , Tingley Brandon
Published: February 2009

Compared to bright star searches, surveys for transiting planets against fainter (V = 12–18) stars have the advantage of much higher sky densities of dwarf star primaries, which afford easier detection of small transiting bodies. Furthermore, deep searches are capable of probing a wider range of stellar environments. On the other hand, for a given spatial resolution and transit depth, deep searches are more prone to confusion from blended eclipsing binaries. We present a powerful mitigation strategy for the blending problem that includes the use of image deconvolution and high-resolution imaging. The techniques are illustrated with Lupus-TR-3 and very recent IR imaging with PANIC on Magellan. The results are likely to have implications for the CoRoT and KEPLER missions designed to detect transiting planets of terrestrial size.
Predicting the Yields of Photometric Surveys for Transiting Planets
Authors: Beatty Thomas G.
Published: February 2009

Observing extrasolar planetary transits is one of the only ways that we may infer the masses and radii of planets outside the Solar System. As such, the detections made by photometric transit surveys are one of the only foreseeable ways that the areas of planetary interiors, system dynamics, migration, and formation will acquire more data. Predicting the yields of these surveys therefore serves as a useful statistical tool. Predictions allows us to check the efficiency of transit surveys (“are we detecting all that we should?”) and to test our understanding of the relevant astrophysics (“what parameters affect predictions?”). Furthermore, just the raw numbers of how many planets will be detected by a survey can be interesting in its own right. Here, we look at two different approaches to modeling predictions (forward and backward), and examine three different transit surveys (TrES, XO, and Kepler). In all cases, making predictions provides valuable insight into both extrasolar planets and the surveys themselves, but this must be tempered by an appreciation of the uncertainties in the statistical cut-offs used by the transit surveys.
Searching for the secondary eclipse of CoRoT-Exo-2b and its transit timing variations
Authors: Alonso Roi , Aigrain Suzanne , Pont Frédéric , Mazeh Tsevi ,   the CoRoT Exoplanet Science Team
Published: February 2009

With more than 80 transits observed in the CoRoT lightcurve with a cadence of 32 s, CoRoT-Exo-2b provides an excellent case to search for the secondary eclipse of the planet, with an expected signal of less than 10−4 in relative flux. The activity of the star causes a modulation on the flux that makes the detection of this signal challenging. We describe the technique used to seek for the secondary eclipse, that leads to a tentative 2.5σ detection of a 5.5×10−5 eclipse. If the effect of the spots are not taken into account, the times of transit centers will also be affected. They could lead to an erroneous detection of periodic transit timing variations of ~20 s and with a 7.45 d period. By measuring the transit central times at different depths of the transit (transit bisectors), we show that there are no such periodic variations in the CoRoT-Exo-2b O-C residuals larger than ~10 s.
Towards the Albedo of an Exoplanet: MOST Satellite Observations of Bright Transiting Exoplanetary Systems
Authors: Rowe Jason F. , Matthews Jaymie M. , Seager Sara , Sasselov Dimitar , Kuschnig Rainer , Guenther David B. , Moffat Anthony F. J. , Rucinski Slavek M. , Walker Gordon A. H. , Weiss Werner W.
Published: February 2009

The Canadian MOST satellite is a unique platform for observations of bright transiting exoplanetary systems. Providing nearly continuous photometric observations for up to 4 weeks, MOST can produce important observational data to help us learn about the properties of exosolar planets. We review our current observations of HD 209458 and HD 189733 with implications for the albedo and our progress towards detecting reflected light from an exoplanet.
What to Expect from Transiting Multiplanet Systems
Authors: Fabrycky Daniel C.
Published: February 2009

So far radial velocity measurements have discovered ~25 stars to host multiple planets. The statistics imply that many of the known hosts of transiting planets should have additional planets, yet none have been solidly detected. They will be soon, via complementary search methods of RV, transit-time variations of the known planet, and transits of the additional planet. When they are found, what can transit measurements add to studies of multiplanet dynamical evolution? First, mutual inclinations become measurable, for comparison to the solar system's disk-like configuration. Such measurements will give important constraints to planet-planet scattering models, just as the radial velocity measurements of eccentricity have done. Second, the Rossiter-McLaughlin effect measures stellar obliquity, which can be modified by two-planet dynamics with a tidally evolving inner planet. Third, transit-time variations are exquisitely sensitive to planets in mean motion resonance. Two planets differentially migrating in the disk can establish such resonances, and tidal evolution of the planets can break them, so the configuration and frequency of these resonances as a function of planetary parameters will constrain these processes.
Transits and secondary eclipses of HD 189733 with Spitzer
Authors: Agol Eric , Cowan Nicolas B. , Bushong James , Knutson Heather , Charbonneau David , Deming Drake , Steffen Jason H.
Published: February 2009

We present limits on transit timing variations and secondary eclipse depth variations at 8 microns with the Spitzer Space Telescope IRAC camera. Due to the weak limb darkening in the infrared and uninterrupted observing, Spitzer provides the highest accuracy transit times for this bright system, in principle providing sensitivity to secondary planets of Mars mass in resonant orbits. Finally, the transit data provides tighter constraints on the wavelength-dependent atmospheric absorption by the planet.
Planetary Transits and Tidal Evolution
Authors: Jackson Brian , Barne Rory , Greenberg Richard
Published: February 2009

Transiting planets are generally close enough to their host stars that tides may govern their orbital and thermal evolution. We present calculations of the tidal evolution of recently discovered transiting planets and discuss their implications. The tidal heating that accompanies this orbital evolution can be so great that it controls the planet's physical properties and may explain the large radii observed in several cases, including, for example, TrES-4. Also, since a planet's transit probability depends on its orbit, it evolves due to tides. Current values depend sensitively on the physical properties of the star and planet, as well as on the system's age. As a result, tidal effects may introduce observational biases in transit surveys, which may already be evident in current observations. Transiting planets tend to be younger than non-transiting planets, an indication that tidal evolution may have destroyed many close-in planets. Also the distribution of the masses of transiting planets may constrain the orbital inclinations of non-transiting planets.
The extrasolar planet atmosphere and exosphere: Emission and transmission spectroscopy
Authors: Tinetti Giovanna , Beaulieu Jean-Philippe
Published: February 2009

We have now entered a phase of extrasolar planets characterization: probing their atmospheres for molecules, constraining their horizontal and vertical temperature profiles and estimating the contribution of clouds and hazes. We review here the current situation with ground-based and space-based observations, and present the transmission spectra of HD189733b in the spectral range 0.5-24 microns.
Spectrum and atmosphere models of irradiated transiting giant planets
Authors: Hubeny Ivan , Burrows Adam
Published: February 2009

We show that a consistent fit to observed secondary eclipse data for several strongly irradiated transiting planets demands a temperature inversion (stratosphere) at altitude. Such a thermal inversion significantly influences the planet/star contrast ratios at the secondary eclipse, their wavelength dependences, and, importantly, the day-night flux contrast during a planetary orbit. The presence of the thermal inversion/stratosphere seems to roughly correlate with the stellar flux at the planet. Such temperature inversions might be caused by an upper-atmosphere absorber whose exact nature is still uncertain.
The Atmospheres of Extrasolar Super-Earths
Authors: Miller-Ricci Eliza , Seager Sara , Sasselov Dimitar
Published: February 2009

Extrasolar super-Earths (1-10 M⊕) are likely to exist with a wide range of atmospheres. While a number of these planets have already been discovered through radial velocities and microlensing, it will be the discovery of the firsttransitingsuper-Earths that will open the door to a variety of follow-up observations aimed at characterizing their atmospheres. Super-Earths may fill a large range of parameter space in terms of their atmospheric composition and mass. Specifically, some of these planets may have high enough surface gravities to be able to retain large hydrogen-rich atmosphseres, while others will have lost most of their hydrogen to space over the planet's lifetime, leaving behind an atmosphere more closely resembling that of Earth or Venus. The resulting composition of the super-Earth atmosphere will therefore depend strongly on factors such as atmospheric escape history, outgassing history, and the level of stellar irradiation that it receives. Here we present theoretical models of super-Earth emission and transmission spectra for a variety of possible outcomes of super-Earth atmospheric composition ranging from hydrogen-rich to hydrogen-poor. We focus on how observations can be used to differentiate between the various scenarios and constrain atmospheric composition.
Radiative Hydrodynamical Studies of Irradiated Atmospheres
Authors: Dobbs-Dixon Ian
Published: February 2009

Transiting planets provide a unique opportunity to study the atmospheres of extra-solar planets. Radiative hydrodynamical models of the atmosphere provide a crucial link between the physical characteristics of the atmosphere and the observed properties. Here I present results from 3D simulations which solve the full Navier-Stokes equations coupled to a flux-limited diffusion treatment of radiation transfer. Variations in opacity amongst models leads to a variation in the temperature differential across the planet, while atmospheric dynamics becomes much more variable at longer orbital periods. I also present 3D radiative simulations illustrating the importance of distinguishing between optical and infrared opacities.
KEPLER: Search for Earth-Size Planets in the Habitable Zone
Authors: Borucki William , Koch David , Batalha Natalie , Caldwell Douglas , Christensen-Dalsgaard Jorgen , Cochran William D. , Dunham Edward , Gautier Thomas N. , Geary John , Gilliland Ronald , Jenkins Jon , Kjeldsen Hans , Lissauer Jack J. , Rowe Jason
Published: February 2009

TheKepler Missionis a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.

This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.
The NASA EPOXI mission of opportunity to gather ultraprecise photometry of known transiting exoplanets
Authors: Christiansen Jessie L. , Charbonneau David , A'Hearn Michael F. , Deming Drake , Holman Matthew J. , Ballard Sarah , Weldrake David T. F. , Barry Richard K. , Kuchner Marc J. , Livengood Timothy A. , Pedelty Jeffrey , Schultz Alfred , Hewagama Tilak , Sunshine Jessica M. , Wellnitz Dennis D. , Hampton Don L. , Lisse Carey M. , Seager Sara , Veverka Joseph F.
Published: February 2009

The NASA Discovery mission EPOXI, utilizing the Deep Impact flyby spacecraft, comprises two phases: EPOCh (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation). With EPOCh, we use the 30-cm high resolution visible imager to obtain ultraprecise photometric light curves of known transiting planet systems. We will analyze these data for evidence of additional planets, via transit timing variations or transits; for planetary moons or rings; for detection of secondary eclipses and the constraint of geometric planetary albedos; and for refinement of the system parameters. Over a period of four months, EPOCh observed four known transiting planet systems, with each system observed continuously for several weeks. Here we present an overview of EPOCh, including the spacecraft and science goals, and preliminary photometry results.
Measurements of Stellar Properties through Asteroseismology: A Tool for Planet Transit Studies
Authors: Kjeldsen Hans , Bedding Timothy R. , Christensen-Dalsgaard Jørgen
Published: February 2009

Oscillations occur in stars of most masses and essentially all stages of evolution. Asteroseismology is the study of the frequencies and other properties of stellar oscillations, from which we can extract fundamental parameters such as density, mass, radius, age and rotation period. We present an overview of asteroseismic analysis methods, focusing on how this technique may be used as a tool to measure stellar properties relevant to planet transit studies. We also discuss details of the Kepler Asteroseismic Investigation – the use of asteroseismology on the Kepler mission in order to measure basic stellar parameters. We estimate that applying asteroseismology to stars observed by Kepler will allow the determination of stellar mean densities to an accuracy of 1%, radii to 2–3%, masses to 5%, and ages to 5–10% of the main-sequence lifetime. For rotating stars, the angle of inclination can also be determined.
The WHAT Project
Authors: Shporer A. , Bakos G. Á. , Mazeh T. , Kovács G. , Sipőcz B.
Published: February 2009

WHAT is a small-aperture short focal length automated telescope with an 8.2° × 8.2° field of view, located at the Wise Observatory, Israel. The system is similar to the HATNet telescopes and is aimed at searching for transiting extrasolar planets and variable objects. Operational since 2004, WHAT has accumulated ~100000 exposures of several fields and was part of the discovery of the transiting planet HD147506b. Further description of WHAT can be found at: http://wise-obs.tau.ac.il/~what.
TEST The Tautenburg Exoplanet Search Telescope
Authors: Eigmüller Philipp , Eislöffel Jochen
Published: February 2009

The Tautenburg Exoplanet Search Telescope (TEST) is a robotic telescope system. The telescope uses a folded Schmidt Camera with a 300mm main mirror. The focal length is 940mm and it gives a 2.2° × 2.2° field of view. Dome, mount, and CCD cameras are controlled by a software bundle made by Software Bisque. The automation of the telescope includes selection of the night observing program from a given framework, taking darks and skyflats, field identification, guiding, data taking, and archiving. For the search for transiting exoplanets and variable stars an automated psf photometry based on IRAF and a lightcurve analysis based on ESO-Midas are conducted. The images and the results are managed using a PostgreSQL database.
HAT-South: A Global Network of Southern Hemisphere Automated Telescopes to Detect Transiting Exoplanets
Authors: Bakos G. , Afonso C. , Henning T. , Jordán A. , Holman M. , Noyes R. W. , Sackett P. D. , Sasselov D. , Kovács Gábor , Csubry Z. , Pál A.
Published: February 2009

HAT-South is a network of six identical, fully automated wide field telescopes, to be located at three sites (Chile: Las Campanas, Australia: Siding Springs, and Namibia: HESS site) in the Southern hemisphere. The primary purpose of the network is to detect and characterize a large number of extra-solar planets transiting nearby bright stars, and to explore their diversity. Operation of HAT-South is a collaboration among the Harvard-Smithsonian Center for Astrophysics (CfA), Max Planck Institute for Astronomy (MPIA) and the Australian National University (ANU). The network is expected to be ready for initial science operations in 2009. The three sites will permit near round-the-clock monitoring of selected fields, and the continuous data-stream will greatly enhance recovery of transits. HAT-South will be sensitive to planetary transits down to R≈14 across a 128 square-degrees combined field of view, thereby targeting a large number of dwarfs with feasible confirmation-mode follow-up. We anticipate a yearly detection rate of approximately 25 planets transiting bright stars.
Transit Detection of Radial Velocity Planets
Authors: Kane Stephen R. , von Braun Kaspar
Published: February 2009

The orbital parameters of extra-solar planets have a significant impact on the probability that the planet will transit the host star. This was recently demonstrated by the transit detection of HD 17156b whose favourable eccentricity and argument of periastron dramatically increased its transit likelihood. We present a study which provides a quantitative analysis of how these two orbital parameters affect the geometric transit probability as a function of period. Further, we apply these results to known radial velocity planets and show that there are unexpectedly high transit probabilities for planets at relatively long periods. For a photometric monitoring campaign which aims to determine if the planet indeed transits, we calculate the significance of a null result and the subsequent constraints that may be applied to orbital parameters.
Transiting exo-planets search for MOA-I data
Authors: Fukui A. , Abe F. , Bond I. A. , Furusawa K. , Hearnshow J. B. , Itow Y. , Kamiya K. , Kilmartin P. M. , Masuda K. , Matsubara Y. , Miyake N. , Muraki Y. , Nagaya M. , Noda S. , Ohnishi K. , Saito T. , Sako T. , Sato S. , Sullivan D. J. , Sumi T. , Tristram P. J. , Yanagisawa T. , Yock P. C. M.
Published: February 2009

The Microlensing Observations in Astrophysics (MOA) is a microlensing survey conducted at Mt. John Observatory in New Zealand. We searched transiting planet candidates from the MOA-I Galactic bulge data, which have been obtained with a 61cm B&C telescope from 2000 to 2005 for a microlensing search. Although this survey data were dedicated to microlensing, they are also quite useful for searching transiting objects because of the large number of stars monitored (~7 million) and the long span of the survey (~6 years). From our analysis, we found 58 transiting planet candidates. We are planning to follow up these candidates with high-precision spectroscopic and photometric observations for further selection, toward the detection of planets by radial velocity observations.
De-Trending Time Series Data for Variability Surveys
Authors: Kim Dae-Won , Protopapas Pavlos , Dave Rahul
Published: February 2009

We present an algorithm for the removal of trends in time series data. The trends could be caused by various systematic and random noise sources such as cloud passages, change of airmass or CCD noise. In order to determine the trends, we select template stars based on a hierarchical clustering algorithm. The hierarchy tree is constructed using the similarity matrix of light curves of stars whose elements are the Pearson correlation values. A new bottom-up merging algorithm is developed to extract clusters of template stars that are highly correlated among themselves, and may thus be used to identify the trends. We then use the multiple linear regression method to de-trend all individual light curves based on these determined trends. Experimental results with simulated light curves which contain artificial trends and events are presented. We also applied our algorithm to TAOS (Taiwan-American Occultation Survey) wide field data observed with a 0.5m f/1.9 telescope equipped with 2k by 2k CCD. With our approach, we successfully removed trends and increased signal to noise in TAOS light curves.
Application of the TRUFAS detection algorithm to the first two runs of CoRoT
Authors: Régulo Clara , Almenara Jose M. , Deeg Hans J.
Published: February 2009

TRUFAS is a wavelet-based algorithm developed for the rapid detection of planetary transits in the frame of the COROT space mission. We present the application of this algorithm to the first two observing fields of CoRoT data. In these, CoRoT has observed a total of about 20000 stars. The first CoRoT observing run, IRa01, covers 2 months, February and March 2007, followed by the 5-months long run LRc01. TRUFAS is a very fast algorithm delivering reliable detections. Here we show the results when TRUFAS was applied to these first two sets of data. In the first run, IRa01, TRUFAS found 10 planet candidates and 143 eclipsing binaries and in the LRc01 10 planet candidates and 124 binaries, with a processing that lasted only one night.
Identifying Transiting Circumbinary Planets
Authors: Ofir Aviv
Published: February 2009

Transiting planets manifest themselves by a periodic dimming of their host star by a fixed amount. On the other hand, light curves of transiting circumbinary (CB) planets are expected to be neither periodic nor to have a single depth while in transit, making the Box-Least-Squares (BLS) transit detection method almost ineffective. Therefore, a modified version for the identification of CB planets was developed - CB-BLS. We show that using CB-BLS it is possible to find CB planets in the residuals of light curves of eclipsing binaries (EBs) that have noise levels of 1% or more. Using CB-BLS will allow us to use the massive ground- and space-based photometric surveys to look for these objects. Detecting transiting CB planets is expected to have a wide range of implications. For instance, the frequency of CB planets depends on the planetary formation mechanism - and planets in close pairs of stars provide a most restrictive constraint on planet formation models. Furthermore, understanding very high precision light curves is limited by stellar parameters - and since for EBs the stellar parameters are much better determined, the resultant planetary structure models will have significantly smaller error bars, maybe even small enough to challenge theory.
An algorithm for the detection of transits of planets around eclipsing binaries in CoRoT
Authors: Almenara Jose Manuel , Deeg Hans J. , Lázaro Carlos , Arévalo María Jesús
Published: February 2009

We present a matched filter algorithm to detect transits of planets that orbit both components of close eclipsing binaries in CoRoT targets. The formation of binary systems surrounded by disks is one of the most common outcomes of stellar formation; their detection would therefore constitute an important discovery. In an eclipsing binary system, the binary-planet alignment gives raised transit probabilities and the special transit shapes from circumbinary planets provide a unique identifier for their planetary nature; the problems of false alarms are largely avoided. CoRoT data have unprecedented time coverage and photometric precision that make them especially suitable for the search of transits of planets across eclipsing binaries. No reliable detections of circumbinary planets have been reported yet, and their discovery would constitute a new class of planets.
UTM, a universal simulator for lightcurves of transiting systems
Authors: Deeg Hans
Published: February 2009

The Universal Transit Modeller (UTM) is a light-curve simulator for all kinds of transiting or eclipsing configurations between arbitrary numbers of several types of objects, which may be stars, planets, planetary moons, and planetary rings. Applications of UTM to date have been mainly in the generation of light-curves for the testing of detection algorithms. For the preparation of such test for the Corot Mission, a special version has been used to generate multicolour light-curves in Corot's passbands. A separate fitting program, UFIT (Universal Fitter) is part of the UTM distribution and may be used to derive best fits to light-curves for any set of continuously variable parameters. UTM/UFIT is written in IDL code and its source is released in the public domain under the GNU General Public License.
Analytic approximations for transit light curve observables and uncertainties
Authors: Carter Joshua A. , Yee Jennifer C. , Eastman Jason , Gaudi B. Scott , Winn Joshua N.
Published: February 2009

The light curve of an exoplanetary transit can be used to estimate the planetary radius and other parameters of interest. Because accurate parameter estimation is a non-analytic and computationally intensive problem, it is often useful to have analytic approximations for the parameters as well as their uncertainties and covariances. Here we give such formulas, for the case of an exoplanet transiting a star with a uniform brightness distribution. When limb darkening is significant, our parameter sets are still useful, although our analytic formulas underpredict the covariances and uncertainties.
Analysis of the light and radial velocity curves of transiting extra-solar planets
Authors: Giménez Alvaro
Published: February 2009

Several approaches have been followed for the analysis of the light curves of transiting extra-solar planets. From simple approximate algorithms and synthetic models to semi-analytical complete solutions. The different alternatives are discussed with their strengths and weaknesses. Analytical expressions can also provide a deeper insight into the main system parameters from the measurement of a few strategic points describing the shape of the light curve.
Co-ordinated Follow-Up of Transiting Planet Candidates with Robotic Telescope Facilities
Authors: Street R. A. , Lister T. A.
Published: February 2009

There are now several large photometric surveys scanning millions of stellar light-curves for signs of planetary transits. All produce large candidate lists with a high false alarm rate, so that further observations are required to confirm new detections. One such survey, SuperWASP, produced ~150 candidates during the 2007–2008 season. Here we describe our campaign to follow-up 86 of these candidates using the robotic facilities of Las Cumbres Observatory Global Telescope Network and the Tenagra-II robotic telescope in Arizona. The aim of these observations was to eliminate false positives as far as possible ahead of spectroscopic follow-up and to provide additional photometry to help characterise the surviving targets.
Burrell-Optical-Kepler Survey (BOKS): A Variability Search in the Kepler Field
Authors: Proctor Amanda L. , Howell Steve B. , Sherry William H. , von Braun Kaspar , Everett Mark E. , Feldmeir John J. , Ciardi David R.
Published: February 2009

We present the results of eighteen non-continuous nights of time series photometric observations of a 1.25 deg2 field in Cygnus centered on the NASA Kepler Mission field of view. Using the Case Western Burrell Schmidt telescope we gathered a dataset containing light curves of roughly 30,000 stars with 14 < r < 19. We have statistically examined each light curve to test for variability, periodicity, and unusual light curve trends, including exoplanet transits. We present a summary of our photometric project including a characterization of the level and content of stellar variability in this field. We will also discuss our potential exoplanet candidates.
HD 17156 : a progress report
Authors: Barbieri Mauro , Alonso Roi , Cecconi M. , Claudi R. U. , Desidera S. , Endl M. , Fiorenzano A. F. Martinez , Gratton R.
Published: February 2009

We present an analysis of the HD planetary system based on a photometric transit dataset and radial velocities obtained on 3 December 2007. We also present limits on the presence of close stellar companions based on high resolution images.
Determination of stellar, orbital and planetary parameters using complete Monte-Carlo analysis – the case of HAT-P-7b
Authors: Pál András , Bakos Gáspár Á. , Noyes Robert W. , Torres Guillermo
Published: February 2009

The recently discovered transiting very hot Jupiter, HAT-P-7b, a planet detected by the telescopes of HATNet, turned out to be among the ones subjected to the highest irradiation from the parent star. In order to best characterize this particular planet, we carried out an analysis based on a complete and simultaneous Monte-Carlo solution using all available data. We included the discovery light curves, partial follow-up light curves, the radial velocity data, and we used the stellar evolution models to infer the stellar properties.

This self-consistent way of modeling provides the most precise estimate of the a posteriori distributions of all of the system parameters of interest, and avoids making assumptions on the values and uncertainties of any of the internally derived variables describing the system. This analysis demonstrates that even partial light curve information can be valuable. This may become very important for future discoveries of planets with longer periods – and therefore longer transit durations – where the chance of observing a full event is small.
Observations of the transiting planet TrES-2 with the AIU Jena telescope in Großschwabhausen
Authors: Raetz S. , Mugrauer M. , Schmidt T. O. B. , Roell T. , Eisenbeiss T. , Hohle M. , Seifahrt A. , Koeltzsch A. , Vaňko M. , Broeg Ch. , Koppenhoefer J. , Neuhäuser R.
Published: February 2009

We have started high precision photometric monitoring observations at the AIU Jena observatory in Großschwabhausen near Jena in fall 2006. We used a 25.4cm Cassegrain telescope equipped with a CCD-camera mounted piggyback on a 90cm telescope. To test the attainable photometric precision, we observed stars with known transiting planets. We could recover all planetary transits observed by us.

We observed the parent star of the transiting planet TrES-2 over a longer period in Großschwabhausen. Between March and November 2007 seven different transits and almost a complete orbital period were analyzed. Overall, in 31 nights of observation 3423 exposures (in total 57.05h of observation) of the TrES-2 parent star were taken. Here, we present our methods and the resulting light curves. Using our observations we could improve the orbital parameters of the system.
Transit observation at the observatory in Großschwabhausen: XO-1b and TrES-1
Authors: Vaňko M. , Raetz S. , Mugrauer M. , Schmidt T. O. B. , Roell T. , Eisenbeiss T. , Hohle M. , Seifahrt A. , Koeltzsch A. , Broeg C. , Koppenhoefer J. , Neuhäuser R.
Published: February 2009

We report on observations of transit events of the transiting planets XO-1b and TrES-1 with the AIU Jena telescope in Großschwabhausen. Based on our (IR) photometry (in March 2007) and available transit timings (SuperWASP, XO and TLC-project-data) we improved the orbital period of XO-1b (P = 3.941497 ± 0.000006) and TrES-1 (P = 3.0300737 ± 0.000006), respectively. The new ephemeris for the both systems are presented.
Optical Follow up Photometry of the Transiting Extrasolar Planet XO-2
Authors: Fernandez Jose M. , Holman Matthew J. , Winn Joshua N.
Published: February 2009

We present three full z-band transit light curves for the extrasolar planet XO-2 obtained with KeplerCam and the FLWO 1.2m telescope. The system parameters were determined fitting the data to transit models using a Markov Chain Monte Carlo simulation (MCMC). The main results presented in this poster are revised values for the parameters Rp/Rs, a/Rs and b.
Observing exoplanets from Brazil: the first try
Authors: Saito Roberto , Silva Paulo Henrique , Kanaan Antonio , Schoenell William , Fraga Luciano , Bruch Albert
Published: February 2009

This project consists in mapping a 4-square-degree region searching for exoplanets using the transit method. This “mini-survey” will be the first use of the 16″ robotic telescope developed by Universidade Federal de Santa Catarina (UFSC-Brazil) and Laboratório Nacional de Astrofísica (LNA/MCT-Brazil). The chosen region is over the Columba constellation and our first observations have shown that we have enough signal-to-noise ratio to search for transits on about 20,000 stars with ~13 < I < 16 mag, a magnitude range between the OGLE and HAT projects. In this star sample we expect to find about a dozen planets with transits duration of 1-3 hours and magnitude depth from 0.001 to 0.010 mag. As for other projects, all information will became public as a VO service.
Radio cyclotron emission from extra-solar planets
Authors: Smith Alexis , Cameron Andrew , Greaves Jane , Jardine Moira , Langston Glen , Backer Donald
Published: February 2009

We present results from an attempt to detect radio emission from the interaction between a transiting extra-solar planet and its host star. We determine a new upper limit of 47 mJy on the radio flux density from HD 189733b, in the frequency range 327–347 MHz.
MOST Spacebased Photometry of HD 189733: Precise Timing Measurements for Transits Across an Active Star
Authors: Miller-Ricci E. , Rowe J. F. , Sasselov D. , Matthews J. M. , Kuschnig R. , Croll B. , Guenther D. B. , Moffat A. F. J. , Rucinski S. , Walker G. A. H , Weiss W. W.
Published: February 2009

We have measured transit times for HD 189733 passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband photometry of this system was obtained with the MOST (Microvariability & Oscillations of STars) space telesope during 21 days in August 2006, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. We find no variations above the level of ±45 s, ruling out planets in the Earth-to-Neptune mass range in a number of resonant orbits. We find that a number of complications can arise in measuring transit times for a planet transiting an active star with large star spots. However, such transiting systems are also useful in that they can help to constrain and test spot models. This has implications for the large number of transiting systems expected to be discovered by the CoRoT and Kepler missions.
Preliminary Results on HAT-P-4, TrES-3, XO-2, and GJ 436 from the NASA EPOXI Mission
Authors: Ballard Sarah , Charbonneau David , A'Hearn Michael F. , Deming Drake , Holman Matthew J. , Christiansen Jessie L. , Weldrake David T. F. , Barry Richard K. , Kuchner Marc J. , Livengood Timothy A. , Pedelty Jeffrey , Schultz Alfred , Hewagama Tilak , Sunshine Jessica M. , Wellnitz Dennis D. , Hampton Don L. , Lisse Carey M. , Seager Sara , Veverka Joseph F.
Published: February 2009

EPOXI (EPOCh + DIXI) is a NASA Discovery Program Mission of Opportunity using the Deep Impact flyby spacecraft. The EPOCh (Extrasolar Planet Observation and Characterization) Science Investigation will gather photometric time series of known transiting exoplanet systems from January through August 2008. Here we describe the steps in the photometric extraction of the time series and present preliminary results of the first four EPOCh targets.
Toward a homogeneous set of transiting planet parameters
Authors: Torres Guillermo , Winn Joshua N. , Holman Matthew J.
Published: February 2009

With 40 or more transiting exoplanets now known, the time is ripe to seek patterns and correlations among their observed properties, which may give important insights into planet formation, structure, and evolution. This task is made difficult by the widely different methodologies that have been applied to measure their properties in individual cases. Furthermore, in many systems our knowledge of the planet properties is limited by the knowledge of the properties of the parent stars. To address these difficulties we have undertaken the first comprehensive analysis of the data for 23 transiting planets using a uniform methodology. We revisit several of the recently proposed correlations, and find new ones involving the metallicity of the parent stars.
Eccentric Planets & Transit Time Variation
Authors: Kipping David M. , Ribas Ignasi , Font-Ribera Andreu
Published: February 2009

For an extrasolar planet on an eccentric orbit, the orbital velocity is constantly changing, even during a planetary transit. This changing orbital velocity will, in general, cause lightcurve assymetry. The asymmetry causes the mid-transit time to be slightly off-centre from the halfway point between transit ingress and egress. For GJ436b, we estimate that the mid-transit time is shifted by 20 seconds. In the case of a system experiencing secular changes, this difference will lead to a long period transit time variation (L-TTV) signal, under the typical definition of the mid-transit time. In this work, we describe the origins of the effect and evaluate it in the case of GJ436b experiencing hypothetical secular changes. We predict L-TTV could be used to map secular changes in such systems.
A Search for Exotrojans in Transiting Exoplanetary systems
Authors: Madhusudhan N. , Winn Joshua N.
Published: February 2009

We present a search for Trojan companions to 25 transiting exoplanets. We use the technique of Ford & Gaudi, in which a difference is sought between the observed transit time and the transit time that is calculated by fitting a two-body Keplerian orbit to the radial-velocity data. This technique is sensitive to the imbalance of mass at the L4/L5 points of the planet-star orbit. No companions were detected. The median 2σ upper limit is 60 M⊕, and the most constraining limit is 2.5 M⊕ for the case of GJ 436.
Astro-comb: revolutionizing precision spectroscopy in astrophysics
Authors: Cramer Claire E. , Li Chih-Hao , Benedick Andrew J. , Glenday Alexander G. , Kärtner Franz X. , Phillips David F. , Sasselov Dimitar , Szentgyorgyi Andrew , Walsworth Ronald L.
Published: February 2009

Searches for extrasolar planets using the periodic Doppler shift of stellar spectral lines have recently achieved a precision better than 60cm/s. To find a 1-Earth mass planet in an Earth-like orbit, a precision of 5cm/s is necessary. The combination of a laser frequency comb with a Fabry-Perot filtering cavity has been suggested as a promising approach to achieve such Doppler shift resolution via improved spectrograph wavelength calibration. Here we report the fabrication of such a filtered laser comb with up to 40 GHz (~1 Angstrom) line spacing, generated from a 1 GHz repetition-rate source, without compromising long-term stability, reproducibility or spectral resolution. This wide-line-spacing comb (astro-comb) is well matched to the resolving power of high-resolution astrophysical spectrographs. The astrocomb should allow a precision as high as 1cm/s in astronomical readial velocity measurements.