- ID:
- ivo://CDS.VizieR/J/AJ/154/134
- Title:
- Planetary-mass brown dwarfs in the Taurus SFR
- Short Name:
- J/AJ/154/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the initial results from a survey for planetary-mass brown dwarfs in the Taurus star-forming region. We have identified brown dwarf candidates in Taurus using proper motions and photometry from several ground- and space- based facilities. Through spectroscopy of some of the more promising candidates, we have found 18 new members of Taurus. They have spectral types ranging from mid-M to early-L, and they include the four faintest known members in extinction-corrected K_s_, which should have masses as low as ~4-5 M_Jup_ according to evolutionary models. Two of the coolest new members (M9.25, M9.5) have mid-IR excesses that indicate the presence of disks. Two fainter objects with types of M9-L2 and M9-L3 also have red mid-IR colors relative to photospheres at =<L0, but since the photospheric colors are poorly defined at >L0, it is unclear whether they have excesses from disks. We also have obtained spectra of candidate members of the IC 348 and NGC 1333 clusters in Perseus that were identified by Luhman et al. Eight candidates are found to be probable members, three of which are among the faintest and least-massive known members of the clusters (~5 M_Jup_).
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/656/A51
- Title:
- Planetary nebulae in Gaia EDR3
- Short Name:
- J/A+A/656/A51
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The Gaia Early Data Release 3 (EDR3), published in December 2020, features improved photometry and astrometry compared to that published in the previous DR2 file and includes a substantially larger number of sources, of the order of 2000 million, making it a paradigm of big data astronomy. Many of the central stars of planetary nebulae (CSPNe) are inherently faint and difficult to identify within the field of the nebula itself. Gaia measurements may be relevant not only in identifying the ionising source of each nebula, but also in the study their physical and evolutionary properties. We demonstrate how Gaia data mining can effectively help to solve the issue of central star misidentification, a problem that has plagued the field since its origin. As we did for DR2, our objective is to present a catalogue of CSPNe with astrometric and photometric information in EDR3. From that catalogue, we selected a sample of stars with high-quality astrometric parameters, on which we carried out a more accurate analysis of CSPNe properties. Gaia GBP-GRP colours allow us to select the sources with sufficient temperatures to ionise the nebula. In order to estimate the real colour of a source, it is important to take into account interstellar extinction and, in the case of compact nebulae, nebular extinction when available. In addition, distances derived from EDR3 parallaxes (combined with consistent literature values) can be used to obtain nebular intrinsic properties from those observed. With this information, CSPNe can be plotted in an Hertzsprung-Russell diagram. From information on the spectral classification of the CS (from the literature) and evolutionary models for post-AGB stars, their evolutionary state can then be analysed. Furthermore, EDR3 high-quality astrometric data enable us to search for objects comoving with CSs in the field of each nebula by detecting sources with parallaxes and proper motions similar to those of the CS. We present a catalogue of 2035 PNe with their corresponding CS identification from among Gaia EDR3 sources. We obtain the distances for those with known parallaxes in EDR3 (1725 PNe). In addition, for a sub-sample (405 PNe) with the most accurate distances, we obtain different nebular properties such as their Galactic distribution, radius, kinematic age, and morphology. Furthermore, for a set of 74 CSPNe, we present the evolutionary state (mass and age) derived from their luminosities and effective temperatures from evolutionary models. Finally, we highlight the detection of several wide binary CSPNe through an analysis of the EDR3 astrometric parameters, and we contribute to shedding some light on the relevance of close binarity in CSPNe.
- ID:
- ivo://CDS.VizieR/J/PASP/122/524
- Title:
- Planetary nebulae in MACHO Galactic Bulge
- Short Name:
- J/PASP/122/524
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have examined central stars of planetary nebulae and symbiotic stars found in the MACHO Galactic bulge database to look for variability. We found four central stars of planetary nebulae and eight symbiotic stars that show variability. We examine the variability and the nature of these objects in detail, as well as reporting on the objects that we did not find to be variable.
- ID:
- ivo://CDS.VizieR/J/A+A/508/1011
- Title:
- Planetary transit of TrES-1 and TrES-2
- Short Name:
- J/A+A/508/1011
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set limits for the presence of additional third bodies. Using the IAC 80cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variations in the difference between observed and calculated (based on a fixed ephemeris) transit times. To model possible transit timing variations, we used polynomials of different orders, simulated O-C diagrams corresponding to a perturbing third mass and sinusoidal fits. For each model we calculated the chi-squared residuals and the False Alarm Probability (FAP). For TrES-1 we can exclude planetary companions (>1M_{earth}_) in the 3:2 and 2:1 MMRs having high FAPs based on our transit observations from ground. Additionally, the presence of a light time effect caused by e.g. a 0.09M_{sun}_ mass star at a distance of 7.8AU is possible. As for TrES-2, we found a better ephemeris of Tc=2453957.63512(28)+2.4706101(18)xEpoch and a good fit for a sine function with a period of 0.2days, compatible with a moon around TrES-2 and an amplitude of 57s, but it was not a uniquely low chi-squared value that would indicate a clear signal. In both cases, TrES-1 and TrES-2, we were able to put upper limits on the presence of additional perturbers masses. We also conclude that any sinusoidal variations that might be indicative of exomoons need to be confirmed with higher statistical significance by further observations, noting that TrES-2 is in the field-of-view of the Kepler Space Telescope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/408/1494
- Title:
- Planetary transits of TrES-2 and TrES-3
- Short Name:
- J/MNRAS/408/1494
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first extrasolar planet observations from the 10.4-m Gran Telescopio Canarias (GTC). We used the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) tunable filter imager on the GTC to acquire high-precision, narrow-band photometry of the transits of the giant exoplanets, TrES-2b and TrES-3b. We obtained near-simultaneous observations in two near-infrared wavelengths (790.2 and 794.4nm). We provide normalized flux ratios for each target, where the flux ratio is defined as the target flux divided by the total combined flux from several non-variable reference stars. The flux ratios have been normalized against the baseline (out-of-transit) flux ratio for each target. We provide normalized flux ratios for each target, where the flux ratio is defined as the target flux divided by the total combined flux from several non-variable reference stars. The flux ratios have been normalized against the baseline (out-of-transit) flux ratio for each target.
- ID:
- ivo://CDS.VizieR/J/ApJ/705/1226
- Title:
- Planet-bearing stars in Spitzer
- Short Name:
- J/ApJ/705/1226
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the MIPS camera on the Spitzer Space Telescope, we have searched for debris disks around 104 stars known from radial velocity studies to have one or more planets. Combining this new data with 42 already published observations of planet-bearing stars, we find that 14 of the 146 systems have IR excess at 24 and/or 70um. Only one star, HD 69830, has IR excess exclusively at 24um, indicative of warm dust in the inner system analogous to that produced by collisions in the solar system's asteroid belt. For the other 13 stars with IR excess the emission is stronger at 70um, consistent with cool dust (<100K) located beyond 10AU, well outside of the orbital location of the known planets.
- ID:
- ivo://CDS.VizieR/J/AJ/155/136
- Title:
- Planets orbiting bright stars in K2 campaigns 0-10
- Short Name:
- J/AJ/155/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since 2014, NASA's K2 mission has observed large portions of the ecliptic plane in search of transiting planets and has detected hundreds of planet candidates. With observations planned until at least early 2018, K2 will continue to identify more planet candidates. We present here 275 planet candidates observed during Campaigns 0-10 of the K2 mission that are orbiting stars brighter than 13 mag (in Kepler band) and for which we have obtained high-resolution spectra (R=44000). These candidates are analyzed using the vespa package in order to calculate their false-positive probabilities (FPP). We find that 149 candidates are validated with an FPP lower than 0.1%, 39 of which were previously only candidates and 56 of which were previously undetected. The processes of data reduction, candidate identification, and statistical validation are described, and the demographics of the candidates and newly validated planets are explored. We show tentative evidence of a gap in the planet radius distribution of our candidate sample. Comparing our sample to the Kepler candidate sample investigated by Fulton et al. (2017, J/AJ/154/109), we conclude that more planets are required to quantitatively confirm the gap with K2 candidates or validated planets. This work, in addition to increasing the population of validated K2 planets by nearly 50% and providing new targets for follow-up observations, will also serve as a framework for validating candidates from upcoming K2 campaigns and the Transiting Exoplanet Survey Satellite, expected to launch in 2018.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A45
- Title:
- Pleiades cluster membership probabilities
- Short Name:
- J/A+A/563/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the advent of deep wide surveys, large photometric and astrometric catalogues of literally all nearby clusters and associations have been produced. The unprecedented accuracy and sensitivity of these data sets and their broad spatial, temporal and wavelength coverage make obsolete the classical membership selection methods that were based on a handful of colours and luminosities. We present a new technique designed to take full advantage of the high dimensionality (photometric, astrometric, temporal) of such a survey to derive self-consistent and robust membership probabilities of the Pleiades cluster. We aim at developing a methodology to infer membership probabilities to the Pleiades cluster from the DANCe multidimensional astro-photometric data set in a consistent way throughout the entire derivation. The determination of the membership probabilities has to be applicable to censored data and must incorporate the measurement uncertainties into the inference procedure. We use Bayes-theorem and a curvilinear forward model for the likelihood of the measurements of cluster members in the colour-magnitude space, to infer posterior membership probabilities. The distribution of the cluster members proper motions and the distribution of contaminants in the full multidimensional astro-photometric space is modelled with a mixture-of-Gaussians likelihood. We analyse several representation spaces composed of the proper motions plus a subset of the available magnitudes and colour indices. We select two prominent representation spaces composed of variables selected using feature relevance determination techniques based in Random Forests, and analyse the resulting samples of high probability candidates. We consistently find lists of high probability (p>0.9975) candidates with ~1000 sources, 4 to 5 times more than obtained in the most recent astro-photometric studies of the cluster. Multidimensional data sets require statistically sound multivariate analysis techniques to fully exploit their scientific information content. Proper motions in particular are, as expected, critical for the correct separation of contaminants. The methodology presented here is ready for application in data sets that include more dimensions, such as radial and/or rotational velocities, spectral indices, and variability.
- ID:
- ivo://CDS.VizieR/J/A+A/299/696
- Title:
- Pleiades field Membership probabilities
- Short Name:
- J/A+A/299/696
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of proper motions and photographic B,V magnitudes for stars up to B=19 mag within a region centered near Alcyone is presented. The catalogue is based on MAMA measurements of 8 plates taken with the Tautenburg Schmidt telescope. The survey includes ca. 14500 stars and covers a total field of about 9 square degrees. Membership probabilities, proper motions and B,V magnitudes are listed for 442 stars up to B=19 mag in the Pleiades field.
- ID:
- ivo://CDS.VizieR/J/MNRAS/313/347
- Title:
- Pleiades low-mass stars and brown dwarfs
- Short Name:
- J/MNRAS/313/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a six-square-degree Pleiades survey in I and Z, which is photometrically complete to approximately I_KP_=19.2mag (I_C_=19.6 in the Pleiades). We remove non-cluster contamination on the basis of proper motions and infrared photometry, and present 339 candidate cluster members, 30 of which are fainter than I_KP_=17.5, and are thus strong brown-dwarf candidates.
