- ID:
- ivo://CDS.VizieR/J/ApJ/647/1180
- Title:
- Infrared photometry of Taurus SFR
- Short Name:
- J/ApJ/647/1180
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for new members of the Taurus star-forming region using the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope. With IRAC images of 29.7deg^2^ of Taurus at 3.6, 4.5, 5.8, and 8.0um, we have identified sources with red mid-infrared colors indicative of disk-bearing objects and have obtained optical and infrared spectra of 23 of these candidate members. Through this work, we have discovered 13 new members of Taurus, two of which have spectral types later than M6 and thus are likely to be brown dwarfs, according to the theoretical evolutionary models of Chabrier & Baraffe (2000ApJ...542..464C). This survey indicates that the previous census of Taurus has a completeness of 80% for members with disks. The new members that we have found do not significantly modify the previously measured distributions of Taurus members as a function of position, mass, and extinction. For instance, we find no evidence for a population of highly reddened brown dwarfs ({LAMBDA}_K_~2) that has been missed by previous optical and near-infrared surveys, which suggests that brown dwarf disks are not significantly more flared than disks around stars. In addition to the new members, we also present IRAC photometry for the 149 previously known members that appear within this survey, which includes 27 objects later than M6.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/573/366
- Title:
- Infrared photometry of Trapezium cluster
- Short Name:
- J/ApJ/573/366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the results of a new multiepoch, multiwavelength, near-infrared census of the Trapezium cluster in Orion to construct and analyze the structure of its infrared (K-band) luminosity function. Specifically, we employ an improved set of model luminosity functions to derive this cluster's underlying initial mass function (IMF) across the entire range of mass from OB stars to substellar objects down to near the deuterium-burning limit. The observations were performed at FLWO (Fred Lawrence Whipple Observatory, Smithsonian Astrophysical Observatory), and ESO-NTT (European Southern Observatory, New Technology Telescope), between Dec. 1997 and Marche 2000 (see the "Table 5" section below)
- ID:
- ivo://CDS.VizieR/J/AJ/150/191
- Title:
- Infrared photometry of YSOs in Cygnus-X DR15
- Short Name:
- J/AJ/150/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength study of the young stellar population in the Cygnus-X DR15 region. We studied young stars that were forming or recently formed at and around the tip of a prominent molecular pillar and an infrared dark cloud. Using a combination of ground-based near-infrared, space-based infrared, and X-ray data, we constructed a point source catalog from which we identified 226 young stellar sources, which we classified into evolutionary classes. We studied their spatial distributions across the molecular gas structures and identified several groups that possibly belong to distinct young star clusters. We obtained samples of these groups and constructed K-band luminosity functions that we compared with those of artificial clusters, allowing us to make first order estimates of the mean ages and age spreads of the groups. We used a ^13^CO(1-0) map to investigate the gas kinematics at the prominent gaseous envelope of the central cluster in DR15, and we inferred that the removal of this envelope is relatively slow compared to other cluster regions, in which the gas dispersal timescale could be similar or shorter than the circumstellar disk dissipation timescale. The presence of other groups with slightly older ages, associated with much less prominent gaseous structures, may imply that the evolution of young clusters in this part of the complex proceeds in periods that last 3-5Myr, perhaps after a slow dissipation of their dense molecular cloud birthplaces.
- ID:
- ivo://CDS.VizieR/J/AJ/157/112
- Title:
- Infrared photometry of YSOs in the W4 cloud complex
- Short Name:
- J/AJ/157/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is well known that most of the stars form in rich clusters. However, recent Spitzer observations have shown that a significant number of stars also form in the distributed mode; their origin is not well understood. In this work, we aim to investigate clustered and distributed modes of star formation in the W4 complex. To do so, we identified and characterized the young stellar population associated with the region using homogeneous infrared data sets obtained from the Two Micron All Sky Survey, GLIMPSE, MIPS, and Wide-field Infrared Survey Explorer surveys. We make stellar surface density and minimum spanning tree maps to identify young clusters, and use Spitzer images to identify irradiated structures, such as elephant-trunk-like structures (ETLSs) and pillars in the region. The surface density distribution of the young stellar objects (YSOs) reveals three new clusterings and ~50% distributed protostars in the H II region. The clusters are of low-mass nature but significantly younger than the central cluster IC 1805. We identified ~38 ETLSs in the region, a majority of which consist of one or a few stars at their tips. We find that these stars are low-mass (<2 M_{sun}_) YSOs, located at the outskirts (>17 pc) of the cluster IC 1805 and are part of the scattered distributed population. We argued that the star formation in the ETLSs of W4 is going on possibly due to the triggering effect of the expanding W4 bubble. Although high-resolution photometric and spectroscopic data would be required to confirm the scenario, nonetheless, we discuss the implications of this scenario for our understanding of distributed low-mass star formation in cloud complexes as opposed to other mechanisms such as turbulent fragmentation and dynamical ejection.
- ID:
- ivo://CDS.VizieR/J/A+A/372/245
- Title:
- Infrared properties of barium stars
- Short Name:
- J/A+A/372/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a systematic survey for IRAS associations of barium stars. A total of 155 associations were detected, and IRAS low-resolution spectra exist for 50 barium stars. We use different color-color diagrams from the visual band to 60{mu}m, relations between these colors and the spectral type, the barium intensity, and the IRAS low-resolution spectra to discuss physical properties of barium stars in the infrared. It is confirmed that most barium stars have infrared excesses in the near infrared. However, a new result of this work is that most barium stars have no excesses in the far infrared. This fact may imply that infrared excesses of barium stars are mainly due to the re-emission of energy lost from the Bond-Neff depression. It is also shown that the spectral type and the barium intensity of barium stars are not correlated with infrared colors, but may be correlated with V-K color.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2243
- Title:
- Infrared properties of close pairs of galaxies
- Short Name:
- J/AJ/132/2243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss spectroscopy and IR photometry for a complete sample of ~800 galaxies in close pairs objectively selected from the second Center for Astrophysics redshift survey. We use the Two Micron All Sky Survey to compare near-IR color-color diagrams for our sample with the Nearby Field Galaxy Sample and with a set of IRAS flux-limited pairs from Surace and coworkers. We construct a basic statistical model to explore the physical sources of the substantial differences among these samples. The model explains the spread of near-IR colors and is consistent with a picture in which central star formation is triggered by the galaxy-galaxy interaction before a merger occurs. For 160 galaxies we report new, deep JHK photometry within our spectroscopic aperture, and we use the combined spectroscopic and photometric data to explore the physical conditions in the central bursts.
- ID:
- ivo://CDS.VizieR/J/ApJ/629/288
- Title:
- Infrared sources near AFGL 5142
- Short Name:
- J/ApJ/629/288
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared JHK' and H_2_ v=1-0 S(1) imaging observations of the star-forming region AFGL 5142 are presented. A cluster of young stars is confirmed to be embedded in the dense molecular cloud core. Many point sources are newly detected. The cluster's K'-magnitude distribution and [H-K'] color peak have brighter and redder magnitudes than those outside the cluster. Many of the cluster sources exhibit infrared excesses typical of T Tauri stars, Herbig Ae/Be stars, and protostars. The observations also reveal new H_2_ line emission around the cluster, exhibiting several jets, filaments, and a faint elliptical structure. The jets are associated with the CO outflows in the region. The powering sources of the jets, the CO outflows, and the small faint elliptical structure are identified and analyzed individually. The strong H_2_ jets and faint diffuse emission further confirm that the cluster is in an early stage of evolution.
- ID:
- ivo://CDS.VizieR/J/PASP/115/351
- Title:
- Infrared Southern Cool Carbon Stars
- Short Name:
- J/PASP/115/351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large set of deep, near-IR, objective-prism plates taken along the southern Galactic plane was searched for cool supergiants and carbon stars. Accurate coordinates and charts for 759 carbon stars in two Galactic longitude sectors within 7.5{deg} of the plane, 248{deg}<l<288{deg} and 320{deg}<l<341{deg}, are given, including 289 stars not previously published. Many of the new and known stars are found in the IRAS, DENIS, and 2MASS point-source catalogs. The 2MASS colors and the longitude distribution of cool carbon stars are discussed briefly.
- ID:
- ivo://CDS.VizieR/III/45
- Title:
- Infrared Spectra for 32 Stars
- Short Name:
- III/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Relative fluxes are presented for 46 spectra (30 stars plus the Sun), ranging in spectral type from A0 to M7. Spectra of seven carbon stars are included. Although some spectra cover the wavenumbers from 2500 to 8200, many spectra do not include wavenumbers less than 4000 and there are many gaps as a result of atmospheric absorption.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/45
- Title:
- Infrared spectral properties of M giants
- Short Name:
- J/ApJ/811/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed a sample of 20 M giants with the Infrared Spectrograph on the Spitzer Space Telescope. Most show absorption structure at 6.6-6.8um which we identify as water vapor, and in some cases, the absorption extends from 6.4um into the SiO band at 7.5um. Variable stars show stronger H_2_O absorption. While the strength of the SiO fundamental at 8um increases monotonically from spectral class K0 to K5, the dependence on spectral class weakens in the M giants. As with previously studied samples, the M giants show considerable scatter in SiO band strength within a given spectral class. All of the stars in our sample also show OH band absorption, most noticeably in the 14-17um region. The OH bands behave much like the SiO bands, increasing in strength in the K giants but showing weaker dependence on spectral class in the M giants, and with considerable scatter. An examination of the photometric properties reveals that the V-K color may be a better indicator of molecular band strength than the spectral class. The transformation from Tycho colors to Johnson B-V color is double-valued, and neither B-V nor B_T_-V_T_ color increases monotonically with spectral class in the M giants like they do in the K giants.