- ID:
- ivo://CDS.VizieR/J/ApJ/767/95
- Title:
- Improved stellar parameters of smallest KIC stars
- Short Name:
- J/ApJ/767/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the optical and near-infrared photometry from the Kepler Input Catalog to provide improved estimates of the stellar characteristics of the smallest stars in the Kepler target list. We find 3897 dwarfs with temperatures below 4000K, including 64 planet candidate host stars orbited by 95 transiting planet candidates. We refit the transit events in the Kepler light curves for these planet candidates and combine the revised planet/star radius ratios with our improved stellar radii to revise the radii of the planet candidates orbiting the cool target stars. We then compare the number of observed planet candidates to the number of stars around which such planets could have been detected in order to estimate the planet occurrence rate around cool stars. We find that the occurrence rate of 0.5-4R_{oplus}_ planets with orbital periods shorter than 50 days is 0.90_0.03_^0.04^ planets per star. The occurrence rate of Earth-size (0.5-1.4R_{oplus}_) planets is constant across the temperature range of our sample at 0.51_0.05_^0.06^ Earth-size planets per star, but the occurrence of 1.4-4R_{oplus}_ planets decreases significantly at cooler temperatures. Our sample includes two Earth-size planet candidates in the habitable zone, allowing us to estimate that the mean number of Earth-size planets in the habitable zone is 0.15_0.06_^0.13^ planets per cool star. Our 95% confidence lower limit on the occurrence rate of Earth-size planets in the habitable zones of cool stars is 0.04 planets per star. With 95% confidence, the nearest transiting Earth-size planet in the habitable zone of a cool star is within 21pc. Moreover, the nearest non-transiting planet in the habitable zone is within 5pc with 95% confidence.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2029
- Title:
- Initial masses of W UMa type contact binaries
- Short Name:
- J/MNRAS/430/2029
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- W UMa type binaries have two defining characteristics. These are (i) the effective temperatures of both components are very similar, and (ii) the secondary (currently less massive) component is overluminous for its current mass. We consider the latter to be an indication of its mass before the mass transfer event. For these stars, we define a mass difference ({delta}M) between the mass determined from its luminosity and the present mass determined from fitting the binary orbit. We compare the observed values of the mass difference to stellar models with mass-loss. The range of initial secondary masses that we find for observed W UMa type binaries is 1.3-2.6M_{sun}_. We discover that the A- and the W-subtype contact binaries have different ranges of initial secondary masses. Binary systems with an initial mass higher than 1.8+/-0.1M_{sun}_ become A-subtype while systems with initial masses lower than this become W-subtype. Only 6 per cent of systems violate this behaviour. We also obtain the initial masses of the primaries using the following constraint for the reciprocal of the initial mass ratio: 0<1/q_i_<1. The range of initial masses we find for the primaries is 0.2-1.5M_{sun}_, except for two systems. Finally in comparing our models to observed systems, we find evidence that the mass transfer process is not conservative. We find that only 34 per cent of the mass from the secondary is transferred to the primary. The remainder is lost from the system.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/121
- Title:
- Investigating Tully-Fisher relation with KMOS^3D^
- Short Name:
- J/ApJ/842/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the stellar mass and baryonic mass Tully-Fisher relations (TFRs) of massive star-forming disk galaxies at redshift z~2.3 and z~0.9 as part of the KMOS^3D^ integral field spectroscopy survey. Our spatially resolved data allow reliable modeling of individual galaxies, including the effect of pressure support on the inferred gravitational potential. At fixed circular velocity, we find higher baryonic masses and similar stellar masses at z~2.3 as compared to z~0.9. Together with the decreasing gas-to-stellar mass ratios with decreasing redshift, this implies that the contribution of dark matter to the dynamical mass on the galaxy scale increases toward lower redshift. A comparison to local relations reveals a negative evolution of the stellar and baryonic TFR zero points from z=0 to z~0.9, no evolution of the stellar TFR zero point from z~0.9 to z~2.3, and a positive evolution of the baryonic TFR zero point from z~0.9 to z~2.3. We discuss a toy model of disk galaxy evolution to explain the observed nonmonotonic TFR evolution, taking into account the empirically motivated redshift dependencies of galactic gas fractions and the relative amount of baryons to dark matter on galaxy and halo scales.
- ID:
- ivo://CDS.VizieR/J/ApJ/694/546
- Title:
- IR dust bubbles. II. YSOs model parameters
- Short Name:
- J/ApJ/694/546
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of late-O/early-B-powered, parsec-sized bubbles and associated star formation using Two Micron All Sky Survey, GLIMPSE, MIPSGAL, and MAGPIS surveys. Three bubbles were selected from the Churchwell et al. catalog (2007, Cat. J/ApJ/670/428). We confirm that the structure identified in Watson et al. (2008ApJ...681.1341W) holds in less energetic bubbles, i.e., a photodissociated region, identified by 8um emission due to polycyclic aromatic hydrocarbons surrounding hot dust, identified by 24um emission and ionized gas, and identified by 20cm continuum. We estimate the dynamical age of two bubbles by comparing bubble sizes to numerical models of Hosokawa and Inutsuka. We also identify and analyze candidate young stellar objects using spectral energy distribution (SED) fitting and identify sites of possible triggered star formation. Lastly, we identify likely ionizing sources for two sources based on SED fitting.
- ID:
- ivo://CDS.VizieR/J/A+A/420/507
- Title:
- Isolated massive white dwarfs catalog
- Short Name:
- J/A+A/420/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of 112 massive isolated white dwarfs, both magnetic and nonmagnetic, with masses M>0.8M_{sun}_. Mass determinations and other parameters of white dwarfs were compiled from the available literature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/1034
- Title:
- IZJHKL' photometry of NGC 6611
- Short Name:
- J/MNRAS/392/1034
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 6611 is the massive young cluster (2-3Myr) that ionizes the Eagle Nebula. We present very deep photometric observations of the central region of NGC 6611 obtained with the Hubble Space Telescope and the following filters: ACS/WFC F775W and F850LP and NIC2 F110W and F160W, loosely equivalent to ground-based IZJH filters. This survey reaches down to I~26mag. We construct the initial mass function (IMF) from ~1.5M_{sun}_ well into the brown dwarf regime (down to ~0.02M_{sun}_). We have detected 30-35 brown dwarf candidates in this sample. The low-mass IMF is combined with a higher-mass IMF constructed from the ground-based catalogue from Oliveira et al. We compare the final IMF with those of well-studied star-forming regions: we find that the IMF of NGC 6611 more closely resembles that of the low-mass star-forming region in Taurus than that of the more massive Orion Nebula Cluster. We conclude that there seems to be no severe environmental effect in the IMF due to the proximity of the massive stars in NGC 6611.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/4150
- Title:
- JCMT Gould Belt Survey: W40 complex
- Short Name:
- J/MNRAS/460/4150
- Date:
- 14 Jan 2022 11:14:19
- Publisher:
- CDS
- Description:
- We present SCUBA-2 450{mu}m and 850{mu}m observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, {beta}=1.8, and a beam convolution kernel to achieve a common 14.8-arcsec resolution. We identify 82 clumps ranging between 10 and 36K with a mean temperature of 20+/-3K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 10^5^cm^-3^. 13 of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70{mu}m images. From JCMT HARP observations of the ^12^CO 3-2 line, we find contamination of the 850{mu}m band of up to 20 per cent. We investigate the free-free contribution to SCUBA-2 bands from large-scale and ultracompact HII regions using archival VLA data and find the contribution is limited to individual stars, accounting for 9 per cent of flux per beam at 450{mu}m or 12 per cent at 850{mu}m in these cases. We conclude that radiative heating has potentially influenced the formation of stars in the Dust Arc sub-region, favouring Jeans stable clouds in the warm east and fragmentation in the cool west.
- ID:
- ivo://CDS.VizieR/J/PASJ/58/L29
- Title:
- JHK photometry of low-mass stars in BRC 14
- Short Name:
- J/PASJ/58/L29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a deep near-infrared survey of a bright-rimmed molecular cloud, BRC 14 (IC 1848A). The 10{sigma} limiting magnitude of the survey is 17.7mag at the K-band. Seventy-four sources are classified as young stellar object (YSO) candidates based on a near-infrared color-color diagram. The faintest YSO candidates may have masses on the order of tenths of the solar mass, assuming an age of 1Myr. We examined three values as indicators of star formation: fraction of the YSO candidates, extinctions of all sources, and near-infrared excesses of the YSO candidates. All indicators increase from outside of the rim to the center of the molecular cloud, which suggests that the formation of the low-mass stars in the BRC 14 region proceeds from outside to the center of the cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/612/L6
- Title:
- j-M law from dwarf to massive spirals
- Short Name:
- J/A+A/612/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a {LAMBDA} CDM Universe, the specific stellar angular momentum (j*) and stellar mass (M*) of a galaxy are correlated as a consequence of the scaling existing for dark matter haloes (jh{prop.to}2/3). The shape of this law is crucial to test galaxy formation models, which are currently discrepant especially at the lowest masses, allowing to constrain fundamental parameters, such as, for example, the retained fraction of angular momentum. In this study, we accurately determine the empirical j*-M* relation (Fall relation) for 92 nearby spiral galaxies (from S0 to Irr) selected from the Spitzer Photometry and Accurate Rotation Curves (SPARC) sample in the unprecedented mass range 7<~logM*/M_{sun}_<~11.5. We significantly improve all previous estimates of the Fall relation by determining j* profiles homogeneously for all galaxies, using extended HI rotation curves, and selecting only galaxies for which a robust j* could be measured (converged j*(<R) radial profile). We find the relation to be well described by a single, unbroken power-law j*{alpha}M*^{alpha}^ over the entire mass range, with {alpha}=0.55+/-0.02 and orthogonal intrinsic scatter of 0.17+/-0.01dex. We finally discuss some implications of this fundamental scaling law for galaxy formation models and, in particular, the fact that it excludes models in which discs of all masses retain the same fraction of the halo angular momentum.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A79
- Title:
- J-PLUS white dwarf atmospheric parameters
- Short Name:
- J/A+A/658/A79
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), which provides 12 photometric optical passbands over 2176deg^2^. We analyzed 5926 white dwarfs with r<19.5mag in common between a white dwarf catalog defined from Gaia EDR3 and J-PLUS DR2. We performed a Bayesian analysis by comparing the observed J-PLUS photometry with theoretical models of hydrogen- and helium-dominated atmospheres. We estimated the probability distribution functions for effective temperature (Teff), surface gravity, parallax, and composition; and the probability of having a H-dominated atmosphere (p_H_) for each source. We applied a prior in parallax, using Gaia EDR3 measurements as a reference, and derived a self-consistent prior for the atmospheric composition as a function of Teff. We described the fraction of white dwarfs with a He-dominated atmosphere (f_He_) with a linear function of the effective temperature at 5000<Teff<30000K. We find f_He_=0.24+/-0.01 at Teff=10000K, a change rate along the cooling sequence of 0.14+/-0.02 per 10kK, and a minimum He-dominated fraction of 0.08+/-0.02 at the high-temperature end. We tested the obtained p_H_ by comparison with spectroscopic classifications, finding that it is reliable. We estimated the mass distribution for the 351 sources with distance d<100pc, mass M>0.45M_{sun}_, and Teff>6000K. The result for H-dominated white dwarfs agrees with previous studies, with a dominant M=0.59M_{sun}_ peak and the presence of an excess at M~0.8M_{sun}_. This high-mass excess is absent in the He-dominated distribution, which presents a single peak. The J-PLUS optical data provide a reliable statistical classification of white dwarfs into H- and He-dominated atmospheres. We find a 21+/-3% increase in the fraction of He-dominated white dwarfs from Teff=20000K to Teff=5000K.
