- ID:
- ivo://CDS.VizieR/J/ApJ/792/30
- Title:
- NEOWISE magnitudes for near-Earth objects
- Short Name:
- J/ApJ/792/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft has been brought out of hibernation and has resumed surveying the sky at 3.4 and 4.6 {mu}m. The scientific objectives of the NEOWISE reactivation mission are to detect, track, and characterize near-Earth asteroids and comets. The search for minor planets resumed on 2013 December 23, and the first new near-Earth object (NEO) was discovered 6 days later. As an infrared survey, NEOWISE detects asteroids based on their thermal emission and is equally sensitive to high and low albedo objects; consequently, NEOWISE-discovered NEOs tend to be large and dark. Over the course of its three-year mission, NEOWISE will determine radiometrically derived diameters and albedos for ~2000 NEOs and tens of thousands of Main Belt asteroids. The 32 months of hibernation have had no significant effect on the mission's performance. Image quality, sensitivity, photometric and astrometric accuracy, completeness, and the rate of minor planet detections are all essentially unchanged from the prime mission's post-cryogenic phase.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/784/110
- Title:
- NEOWISE observations of 105 near-Earth objects
- Short Name:
- J/ApJ/784/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Only a very small fraction of the asteroid population at size scales comparable to the object that exploded over Chelyabinsk, Russia has been discovered to date, and physical properties are poorly characterized. We present previously unreported detections of 105 close approaching near-Earth objects (NEOs) by the Wide-field Infrared Survey Explorer (WISE) mission's NEOWISE project. These infrared observations constrain physical properties such as diameter and albedo for these objects, many of which are found to be smaller than 100m. Because these objects are intrinsically faint, they were detected by WISE during very close approaches to the Earth, often at large apparent on-sky velocities. We observe a trend of increasing albedo with decreasing size, but as this sample of NEOs was discovered by visible light surveys, it is likely that selection biases against finding small, dark NEOs influence this finding.
- ID:
- ivo://CDS.VizieR/J/AJ/152/63
- Title:
- NEOWISE reactivation mission: 2nd yr data
- Short Name:
- J/AJ/152/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids (NEAs) and 8885 other asteroids. Of the NEAs, 84% NEAs did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within +/-~20% and +/-~40%, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large (>100m), and have low albedos.
- ID:
- ivo://CDS.VizieR/J/ApJ/814/117
- Title:
- NEOWISE Reactivation mission: 1st yr data
- Short Name:
- J/ApJ/814/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or "NEOWISE" thermal measurements. Diameters are determined to an accuracy of ~20% or better. If good-quality H magnitudes are available, albedos can be determined to within ~40% or better.
- ID:
- ivo://CDS.VizieR/J/AJ/154/168
- Title:
- NEOWISE: thermal model fits for NEOs and MBAs
- Short Name:
- J/AJ/154/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Near-Earth ObjectWide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6 {mu}m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1{sigma}) of previously measured values. Diameters for the MBAs are within 17% (1{sigma}). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.
1926. NEP deep survey at 11um
- ID:
- ivo://CDS.VizieR/J/PASJ/59/S529
- Title:
- NEP deep survey at 11um
- Short Name:
- J/PASJ/59/S529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the properties of 11um selected sources detected in the early data of the North Ecliptic Pole Deep (NEP-Deep) Survey of AKARI. The data set covers 6 wavelength bands from 2.5 to 11um, with exposure times of 10-20 minutes. This field lies within the CFHT survey with four filter bands (g', r', i', z'), enabling us to establish nearly continuous spectral energy distributions (SEDs) for wavelengths ranging from 0.4 to 11um. The main sample studied here consists of 72 sources whose 11um AB magnitudes are equal to or brighter than 18.5 (144uJy), which is complete to more than 90%. The 11um band has an advantage of sampling star-forming galaxies with low-to-medium redshifts, since the prominent PAH feature shifts into this band. As expected, we find that the majority (71%) of 11um bright sources are star-forming galaxies at 0.2~<z~<0.7 with L_IR_~10^10^-10^12^~L_{sun}_ based on detailed modelling of the SEDs. We also find four AGNs lying at various redshifts in the main sample. In addition, we discuss a few sources that have non-typical SEDs of the main sample, including a brown-dwarf candidate, a steep power-law source, a flat-spectrum object, and an early-type galaxy at moderate redshift.
1927. NEP source catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/172/583
- Title:
- NEP source catalog
- Short Name:
- J/ApJS/172/583
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a five-band (u* g' r' i' z') optical photometry catalog of the sources in the North Ecliptic Pole (NEP) region based on deep observations made with MegaCam at CFHT. The source catalog covers about 2 square degree area centered at the NEP and reaches depths of about 26mag for u*, g', r' bands, about 25mag for i' band, and about 24mag for z' band (4{sigma} detection over a 1" aperture). The total number of cataloged sources brighter than r'=23mag is about 56000 including both point sources and extended sources. From the investigation of photometric properties using the color- magnitude diagrams and color-color diagrams, we have found that the colors of extended sources are mostly (u*-r')<3.0 and (g'-z')>0.5. This can be used to separate the extended sources from the point sources reliably, even for the faint source domain where typical morphological classification schemes hardly work efficiently. We have derived an empirical color-redshift relation of the red sequence galaxies using the Sloan Digital Sky Survey data. By applying this relation to our photometry catalog and searching for any spatial overdensities, we have found two galaxy clusters and one nearby galaxy group.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1067
- Title:
- New beta Lyrae and Algol candidates in NSVS
- Short Name:
- J/AJ/136/1067
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have classified 409 objects in the Northern Sky Variability Survey (NSVS) as new beta Lyrae or Algol-type eclipsing binaries. These candidates have outside of eclipse magnitudes of ~10-13. Through automated Fourier analysis routines and some manual inspection, we list the period, eclipse depths, coordinates, an estimate of the time of primary eclipse, and the 2MASS colors for these candidates. This list of new beta Lyrae type candidates greatly increases the number of known systems of this type. We have also identified 37 candidate low-mass, main-sequence pairs (M_1,2_<1M_{sun}_,T<5500K) in the NSVS database. If confirmed, these systems will greatly increase the number of such low-mass systems known as well as help constrain atmospheric models for these types of stars.
- ID:
- ivo://CDS.VizieR/J/AJ/154/195
- Title:
- New binaries in the {epsilon} Cha association
- Short Name:
- J/AJ/154/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Adaptive Optics-aided speckle observations of 47 young stars in the {epsilon} Cha association made at the 4 m Southern Astrophysical Research Telescope in the I-band. We resolved 10 new binary pairs, 5 previously known binaries, and 2 triple systems, also previously known. In the separation range between 4 and 300 au, the 30 association members of spectral types G0 and later host 6 binary companions, leading to the raw companion frequency of 0.010+/-0.04 per decade of separation, comparable to the main sequence dwarfs in the field. On the other hand, all five massive association members of spectral types A and B have companions in this range. We discuss the newly resolved and known binaries in our sample. Observed motions in the triple system {epsilon} Cha, composed of three similar B9V stars, can be described by tentative orbits with periods 13 and ~900 years and a large mutual inclination.
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/903
- Title:
- New brown dwarf discs in Upper Scorpius
- Short Name:
- J/MNRAS/429/903
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour-magnitude and colour-colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19%) lack excess at 3.4 and 4.6{mu}m and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars. We estimate that the time-scale for a typical transition from class II to class III is less than 0.4Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5-10Myr and a disc clearing time-scale significantly shorter than 1Myr.
