- ID:
- ivo://CDS.VizieR/J/A+A/521/A61
- Title:
- Stars associated to Eagle Nebula (M16=NGC6611)
- Short Name:
- J/A+A/521/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive star-forming regions are characterized by intense ionizing fluxes, strong stellar winds and, occasionally, supernovae explosions, all of which have important effects on the surrounding media, on the star-formation process and on the evolution of young stars and their circumstellar disks. We present a multiband study of the massive young cluster NGC 6611 and its parental cloud (the Eagle Nebula) with the aim of studying how OB stars affect the early stellar evolution and the formation of other stars. We search for evidence of triggering of star formation by the massive stars inside NGC 6611 on a large spatial scale (~10 parsec) and ongoing disk photoevaporation in NGC 6611 and how its efficiency depends on the mass of the central stars.
Number of results to display per page
Search Results
6352. Stars in M13 core
- ID:
- ivo://CDS.VizieR/J/AJ/113/669
- Title:
- Stars in M13 core
- Short Name:
- J/AJ/113/669
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the dense core of the globular cluster Messier 13 (NGC 6205) using pre-refurbishment Planetary Camera-I images obtained with the Hubble Space Telescope. Short exposures (60s) through the F555W and F785LP filters (similar to Johnson V and I, respectively) have been used to obtain V and I photometry of 2877 stars brighter than V~20 in a 1.25arcmin^2^ region of the cluster including its core and extending out to r~66arcsec (2.3pc) from its center. The sample is complete to V~=18.3 (the main sequence turnoff) and the 1{sigma} photometric error is about 0.1mag. We find 15 blue straggler star candidates and 10 other possible blue stragglers in this region of M13. Their specific frequency is in the range F_(BSS)=0.04-0.07, comparable to what is observed near the centers of other dense clusters. A comparison between M13's observed V band stellar luminosity function and a theoretical model (Bergbusch & Vandenberg, 1992ApJS...81..163B) for the luminosity function of an old, metal-poor cluster shows that the model predicts too few of the brightest red giants (V~12.5-15) by a factor of two relative to subgiants/turnoff stars (>6{sigma} effect). The radial distributions of red giants, blue stragglers, and subgiants are consistent with one another, and are well fit by a King profile of core radius r_(core)_=38+/-6arcsec (90% confidence limits) or 1.3pc. Stars in the blue horizontal branch of M13, however, appear to be centrally depleted relative to other stellar types. We combine data from three dense ``King model clusters,'' M13, M3, and 47 Tuc, and two post core collapse clusters, M30 and M15, and compare the distributions of various stellar types as a function of (r/r_(half light)_) and (r/r_(core)_). The horizontal branch stars in the combined sample appear to be centrally depleted relative to the giants (97% significance), this depletion is only a 1-2{sigma} effect in each of the clusters taken individually. The blue stragglers in the combined sample are centrally concentrated relative to the giants. (Copyright) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2677
- Title:
- Stars in the Carina dSph galaxy field
- Short Name:
- J/AJ/130/2677
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The question of the existence of active and prominent tidal disruption around various Galactic dwarf spheroidal (dSph) galaxies remains controversial. That debate often centers on the nature (bound vs. unbound) of extended populations of stars claimed to lie outside the bounds of single King profiles fitted to the density distributions of dSph centers. However, the more fundamental issue of the very existence of the previously reported extended populations is still contentious. We present a critical evaluation of the debate centering on one particular dSph, Carina, for which claims both for and against the existence of stars beyond the King limiting radius have been made.
- ID:
- ivo://CDS.VizieR/J/A+A/272/235
- Title:
- Stars in the dark cloud L1251
- Short Name:
- J/A+A/272/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distance of the dark cloud L1251 was estimated from observations made at the Konkoly Observatory between 1985 and 1991. The spectral classification and the H{alpha} emission features were measured on objective-prism plates taken with the 60/80/180 Schmidt telescope; the photometry was derived from observations made on photographic plates with emulsion-filter combinations giving magnitudes in the Johnson photometric system. The distance of the cloud was found to be 300+/-50pc.
- ID:
- ivo://CDS.VizieR/J/AJ/115/2397
- Title:
- Stars in the solar region
- Short Name:
- J/AJ/115/2397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several samples of nearby stars with the most accurate astrometric and photometric parameters are searched for clues to their evolutionary history. The main samples are (1) the main-sequence stars with b-y between 0.29 and 0.59mag (F3 to K1) in the Yale parallax catalog, (2) a group of high-velocity subgiants studied spectroscopically by Ryan & Lambert (1995AJ....109.2068R), and (3) high-velocity main-sequence stars in the extensive investigation by Norris, Bessel, & Pickles (1985ApJS...58..463N). The major conclusions are as follows: (1) The oldest stars (halo), t>=10-12Gyr, have V-velocities (in the direction of Galactic rotation and referred to the Sun) in the range from about -50 to -800km/s and have a heavy-element abundance [Fe/H] of less than about -0.8dex. The age range of these objects depends on our knowledge of globular cluster ages, but if age is correlated with V-velocity, the youngest may be M22 and M28 (V~-50km/s) and the oldest NGC 3201 (V~-500km/s) and assorted field stars. (2) The old disk population covers the large age range from about 2Gyr (Hyades, NGC 752) to 10 or 12Gyr (Arcturus group, 47 Tuc), but the lag (V) velocity is restricted to less than about 120km/s and [Fe/H]>=-0.8 or -0.9dex. The [Fe/H]~-0.8dex division between halo and old disk, near t~10-12Gyr, is marked by a change in the character of the CN index (Cm) and of the blanketing parameter K of the DDO photometry. (3) The young disk population, t<2Gyr, is confined exclusively to a well-defined area of the (U, V) velocity plane. The age separating young and old disk stars is also that separating giant evolution of the Hyades (near main-sequence luminosity) and M67 (degenerate helium cores and a large luminosity rise) kinds. The two disk populations are also separated by such indexes as the g-index of Geveva photometry. There appears to be no obvious need to invoke exogeneous influences to understand the motion and heavy-element abundance distributions of the best-observed stars near the Sun. Individual stars of special interest include the parallax star HD 55575, which may be an equal-component binary, and the high-velocity star HD 220127, with a well-determined space velocity near 1000km/s.
- ID:
- ivo://CDS.VizieR/J/AJ/155/161
- Title:
- Stars nearby Robo-AO Kepler planetary candidates
- Short Name:
- J/AJ/155/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the overall statistical results from the Robo-AO Kepler planetary candidate survey, comprising of 3857 high-angular resolution observations of planetary candidate systems with Robo-AO, an automated laser adaptive optics system. These observations reveal previously unknown nearby stars blended with the planetary candidate host stars that alter the derived planetary radii or may be the source of an astrophysical false positive transit signal. In the first three papers in the survey, we detected 440 nearby stars around 3313 planetary candidate host stars. In this paper, we present observations of 532 planetary candidate host stars, detecting 94 companions around 88 stars; 84 of these companions have not previously been observed in high resolution. We also report 50 more-widely separated companions near 715 targets previously observed by Robo-AO. We derive corrected planetary radius estimates for the 814 planetary candidates in systems with a detected nearby star. If planetary candidates are equally likely to orbit the primary or secondary star, the radius estimates for planetary candidates in systems with likely bound nearby stars increase by a factor of 1.54, on average. We find that 35 previously believed rocky planet candidates are likely not rocky due to the presence of nearby stars. From the combined data sets from the complete Robo-AO KOI survey, we find that 14.5+/-0.5% of planetary candidate hosts have a nearby star with 4", while 1.2% have two nearby stars, and 0.08% have three. We find that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of Jupiter-sized planet candidates have detected nearby stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/507
- Title:
- Stars of Lyman break galaxies at z~5
- Short Name:
- J/ApJ/693/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectral energy distribution (SED) fitting analysis for Lyman break galaxies (LBGs) at z~5 in the Great Observatories Origins Deep Survey North (GOODS-N) and its flanking fields (the GOODS-FF). With the publicly available Infrared Array Camera (IRAC) images in the GOODS-N and IRAC data in the GOODS-FF, we constructed the rest-frame UV to optical SEDs for a large sample (~100) of UV-selected galaxies at z~5. Comparing the observed SEDs with model SEDs generated with a population synthesis code, we derived a best-fit set of parameters (stellar mass, age, color excess, and star formation rate) for each of the sample LBGs. The derived stellar masses range from 10^8^ to 10^11^M_{sun}_ with a median value of 4.1x10^9^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3027
- Title:
- Statisical study of galaxy dust emissions
- Short Name:
- J/MNRAS/421/3027
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Herschel-ATLAS survey to conduct the first large-scale statistical study of the submillimetre properties of optically selected galaxies. Using ~80000 r-band selected galaxies from 126deg^2^ of the GAMA survey, we stack into submillimetre imaging at 250, 350 and 500um to gain unprecedented statistics on the dust emission from galaxies at z<0.35. We find that low-redshift galaxies account for 5 per cent of the cosmic 250-um background (4 per cent at 350um; 3 per cent at 500um), of which approximately 60 per cent comes from 'blue' and 20 per cent from 'red' galaxies (rest-frame g-r).
- ID:
- ivo://CDS.VizieR/J/ApJ/809/25
- Title:
- Stellar and planet properties for K2 candidates
- Short Name:
- J/ApJ/809/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The extended Kepler mission, K2, is now providing photometry of new fields every three months in a search for transiting planets. In a recent study, Foreman-Mackey and collaborators presented a list of 36 planet candidates orbiting 31 stars in K2 Campaign 1. In this contribution, we present stellar and planetary properties for all systems. We combine ground-based seeing-limited survey data and adaptive optics imaging with an automated transit analysis scheme to validate 21 candidates as planets, 17 for the first time, and identify 6 candidates as likely false positives. Of particular interest is K2-18 (EPIC 201912552), a bright (K=8.9) M2.8 dwarf hosting a 2.23+/-0.25 R_{earth}_ planet with T_eq_=272+/-15 K and an orbital period of 33 days. We also present two new open-source software packages which enable this analysis. The first, isochrones, is a flexible tool for fitting theoretical stellar models to observational data to determine stellar properties using a nested sampling scheme to capture the multimodal nature of the posterior distributions of the physical parameters of stars that may plausibly be evolved. The second is vespa, a new general-purpose procedure to calculate false positive probabilities and statistically validate transiting exoplanets.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/106
- Title:
- Stellar and substellar members in Coma Berenices
- Short Name:
- J/ApJ/862/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified stellar and substellar members in the nearby star cluster Coma Berenices, using photometry, proper motions, and distances of a combination of 2MASS, UKIDSS, URAT1, and Gaia/DR2 data. Those with Gaia/DR2 parallax measurements provide the most reliable sample to constrain the distance, averaging 86.7pc with a dispersion of 7.1pc, and age of ~800Myr, of the cluster. This age is older than the 400-600 Myr commonly adopted in the literature. Our analysis, complete within 5{deg} of the cluster radius, leads to identification of 192 candidates, among which, after field contamination is considered, about 148 are true members. The members have J~3mag to ~17.5mag, corresponding to stellar masses 2.3-0.06M_{sun}_. The mass function of the cluster peaks around 0.3M_{sun},_ and in the sense of dN/dm=m^-{alpha}^, where N is the number of members and m is stellar mass, with a slope {alpha}~=0.49+/-0.03 in the mass range 0.3-2.3M_{sun}_. This is much shallower than that of the field population in the solar neighborhood. The slope {alpha}=-1.69+/-0.14 from 0.3M_{sun}_ to 0.06M_{sun}_, the lowest mass in our sample. The cluster is mass-segregated and has a shape elongated toward the Galactic plane. Our list contains nine substellar members, including three new discoveries of an M8, an L1, and an L4 brown dwarfs, extending from the previously known coolest members of late-M types to even cooler types.