- ID:
- ivo://CDS.VizieR/J/AJ/146/34
- Title:
- Infrared photometry of DA white dwarfs from LAMOST
- Short Name:
- J/AJ/146/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of ~640000 objects from the LAMOST pilot survey have been publicly released. In this work, we present a catalog of DA white dwarfs (DAWDs) from the entire pilot survey. We outline a new algorithm for the selection of white dwarfs (WDs) by fitting Sersic profiles to the Balmer H{beta}, H{gamma}, and H{delta} lines of the spectra, and calculating the equivalent width of the CaII K line. Two thousand nine hundred sixty-four candidates are selected by constraining the fitting parameters and the equivalent width of the CaII K line. All the spectra of candidates are visually inspected. We identify 230 DAWDs (59 of which are already included in the Villanova and SDSS WD catalogs), 20 of which are DAWDs with non-degenerate companions. In addition, 128 candidates are classified as DAWDs/subdwarfs, which means the classifications are ambiguous. The result is consistent with the expected DAWD number estimated based on the LEGUE target selection algorithm.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/396/1915
- Title:
- Infrared photometry of Galactic and MC PN
- Short Name:
- J/MNRAS/396/1915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mid-infrared (MIR) photometry for 367 Galactic disc, bulge and Large Magellanic Cloud (LMC) planetary nebulae (PNe), determined using data acquired with the Spitzer Space Telescope, and through the Legacy Programs GLIMPSE II (Galactic Legacy Infrared Mid-plane Survey Extraordinaire II) and SAGE (Surveying the Agents of the Galaxy's Evolution). This has permitted us to make a comparison between the luminosity functions of bulge and LMC PNe, and between the MIR colours of all three categories of source. It is determined that whilst the 3.6 {mu}m luminosity functions of the LMC and bulge sources are likely to be closely similar, the [3.6]-[5.8] and [5.8]-[8-0] indices of LMC nebulae are different from those of their disc and bulge counterparts. This may arise because of enhanced 6.2{mu}m polycyclic aromatic hydrocarbon emission within the LMC sources, and/or as a result of further, and more radical differences between the spectra of LMC and Galactic PNe. We also determine that the more evolved disc sources listed in the Macquarie/AAO/Strasbourg (MASH) catalogues of Parker et al. (2006MNRAS.373...79P) and Miszalski et al. (2008MNRAS.384..525M), Cat. V/127, have similar colours to those of the less evolved (and higher surface brightness) sources in the catalogue of Acker et al. (Cat. V/84), a result which appears at variance with previous studies of these sources.
- ID:
- ivo://CDS.VizieR/J/AJ/137/4072
- Title:
- Infrared photometry of G216-2.5 YSOs
- Short Name:
- J/AJ/137/4072
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The giant molecular cloud G216-2.5, also known as Maddalena's cloud or the Maddalena-Thaddeus cloud, is distinguished by an unusual combination of high gas mass (1-6x10^5^_M{sun}), low kinetic temperatures (10K), and the lack of bright far-IR emission. Although star formation has been detected in neighboring satellite clouds, little evidence for star formation has been found in the main body of this cloud. Using a combination of mid-IR observations with the IRAC and Multiband Imaging Photometer for Spitzer instruments onboard the Spitzer Space Telescope, and near-IR images taken with the Flamingos camera on the KPNO 2.1m telescope, we identify a population of 41 young stars with disks and 33 protostars in the center of the cloud. Most of the young stellar objects are coincident with a filamentary structure of dense gas detected in CS (2->1). These observations show that the main body of G216 is actively forming stars, although at a low stellar density comparable to that found in the Taurus cloud.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1574
- Title:
- Infrared photometry of IC348 members
- Short Name:
- J/AJ/131/1574
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near- and mid-infrared photometry obtained with the Spitzer Space Telescope of 300 known members of the IC 348 cluster. We merge this photometry with existing ground-based optical and near-infrared photometry in order to construct optical-infrared spectral energy distributions (SEDs) for all the cluster members and present a complete atlas of these SEDs.
- ID:
- ivo://CDS.VizieR/J/AJ/144/42
- Title:
- Infrared photometry of 90 KOIs
- Short Name:
- J/AJ/144/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- All transiting planets are at risk of contamination by blends with nearby, unresolved stars. Blends dilute the transit signal, causing the planet to appear smaller than it really is, or produce a false-positive detection when the target star is blended with eclipsing binary stars. This paper reports on high spatial-resolution adaptive optics images of 90 Kepler planetary candidates. Companion stars are detected as close as 0.1" from the target star. Images were taken in the near-infrared (J and Ks bands) with ARIES on the MMT and PHARO on the Palomar Hale 200inch telescope. Most objects (60%) have at least one star within 6" separation and a magnitude difference of 9. Eighteen objects (20%) have at least one companion within 2" of the target star; six companions (7%) are closer than 0.5". Most of these companions were previously unknown, and the associated planetary candidates should receive additional scrutiny. Limits are placed on the presence of additional companions for every system observed, which can be used to validate planets statistically using the BLENDER method. Validation is particularly critical for low-mass, potentially Earth-like worlds, which are not detectable with current-generation radial velocity techniques. High-resolution images are thus a crucial component of any transit follow-up program.
- ID:
- ivo://CDS.VizieR/J/AJ/160/253
- Title:
- Infrared photometry of late-type dwarfs in Kepler Field
- Short Name:
- J/AJ/160/253
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- While it is well-established that giant-planet occurrence rises rapidly with host star metallicity, it is not yet clear if small-planet occurrence around late-type dwarf stars depends on host star metallicity. Using the Kepler Data Release 25 planet candidate list and its completeness data products, we explore planet occurrence as a function of metallicity in the Kepler field's late-type dwarf stellar population. We find that planet occurrence increases with metallicity for all planet radii Rp down to at least Rp~2R{Earth}, and that in the range 2R{Earth}<~Rp<~5R{Earth}, planet occurrence scales linearly with metallicity Z. Extrapolating our results, we predict that short-period planets with Rp<~2R{Earth} should be rare around early-M dwarf stars with [M/H]<~-0.5 or late-M dwarf stars with [M/H]<~+0.0. This dependence of planet occurrence on metallicity observed in the Kepler field emphasizes the need to control for metallicity in estimates of planet occurrence for late-type dwarf stars like those targeted by Kepler's K2 extension and the Transiting Exoplanet Survey Satellite. We confirm the theoretical expectation that the small-planet occurrence-host star metallicity relation is stronger for low-mass stars than for solar-type stars. We establish that the expected solid mass in planets around late-type dwarfs in the Kepler field is comparable to the total amount of planet-making solids in their protoplanetary disks. We argue that this high efficiency of planet formation favors planetesimal accretion over pebble accretion as the origin of the small planets observed by Kepler around late-type dwarf stars.
- ID:
- ivo://CDS.VizieR/J/A+A/488/675
- Title:
- Infrared photometry of mass-losing AGB stars
- Short Name:
- J/A+A/488/675
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asymptotic giant branch (AGB) phases mark the end of the evolution for low- and intermediate-mass stars. Our understanding of the mechanisms through which they eject the envelope and our assessment of their contribution to the mass return to the interstellar medium and to the chemical evolution of Galaxies are hampered by poor knowledge of their luminosities and mass loss rates, both for C-rich and for O-rich sources. We plan to establish criteria permitting a more quantitative determination of luminosities (and subsequently of mass loss rates) for the various types of AGB stars on the basis of infrared fluxes. In this paper, in particular, we concentrate on O-rich and s-element-rich MS, S stars and include a small sample of SC stars. We reanalyze the absolute bolometric magnitudes and colors of MS, S, SC stars on the basis of a sample of intrinsic (single) and extrinsic (binary) long period variables. We derive bolometric corrections as a function of near- and mid-infrared colors, adopting as references a group of stars for which the spectral energy distribution could be reconstructed in detail over a large wavelength range. We determine the absolute HR diagrams, and compare luminosities and colors of S-type giants with those, previously derived, of C-rich AGB stars. Luminosity estimates are also verified on the basis of existing period-luminosity relations valid for O-rich Miras. S star bolometric luminosities are almost indistinguishable from those of C-rich AGB stars. On the contrary, their circumstellar envelopes are thinner and less opaque. Despite this last property the IR wavelengths remain dominant, with the bluest stars having their maximum emission in the H or K(short) bands. Near-to-mid infrared color differences are in any case smaller than for C stars. Based on period-luminosity relations for O-rich Miras and on Magnitude-color relations for the same variables we show how approximate distances (hence intrinsic parameters) for sources of so far unknown parallax can be inferred. We argue that most of the sources have a rather small mass (<2M_{sun}_); dredge-up might then be not effective enough to let the C/O ratio exceed unity.
- ID:
- ivo://CDS.VizieR/J/ApJ/675/1319
- Title:
- Infrared photometry of NGC 3603
- Short Name:
- J/ApJ/675/1319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the initial mass function (IMF) of one of the most massive Galactic star-forming regions NGC 3603 to answer a fundamental question in current astrophysics: is the IMF universal, or does it vary? Using our very deep, high angular resolution JHKSL' images obtained with NAOS-CONICA at the VLT at ESO, we have successfully revealed the stellar population down to the subsolar mass range in the core of the starburst cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/129/656
- Title:
- Infrared photometry of NGC 6791
- Short Name:
- J/AJ/129/656
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep JHK photometry of the old and metal-rich open cluster NGC 6791. The photometry reaches below the main-sequence turnoff to K~16.5mag. We combine our photometry with that from Stetson et al. (2003, Cat. <J/PASP/115/413>) to provide color-magnitude diagrams showing K versus J-K, K versus V-K, and V versus V-K.
- 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.
