- ID:
- ivo://CDS.VizieR/J/ApJ/813/83
- Title:
- Multiple star formation in Ophiuchus
- Short Name:
- J/ApJ/813/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conduct a multiplicity survey of members of the {rho} Ophiuchus cloud complex with high-resolution imaging to characterize the multiple-star population of this nearby star-forming region and investigate the relation between stellar multiplicity and star and planet formation. Our aperture masking survey reveals the presence of five new stellar companions beyond the reach of previous studies, but does not result in the detection of any new substellar companions. We find that 43+/-6% of the 114 stars in our survey have stellar-mass companions between 1.3 and 780 AU, while 7_-5_^+8^% host brown dwarf companions in the same interval. By combining this information with knowledge of disk-hosting stars, we show that the presence of a close binary companion (separation <40AU) significantly influences the lifetime of protoplanetary disks, a phenomenon previously seen in older star-forming regions. At the ~1-2Myr age of our Ophiuchus members ~2/3 of close binary systems have lost their disks, compared to only ~30% of single stars and wide binaries. This has a significant impact on the formation of giant planets, which are expected to require much longer than 1 Myr to form via core accretion and thus planets formed via this pathway should be rare in close binary systems.
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- ID:
- ivo://CDS.VizieR/J/ApJ/731/8
- Title:
- Multiple star formation in Taurus-Auriga
- Short Name:
- J/ApJ/731/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a high-resolution imaging study of the Taurus-Auriga star-forming region in order to characterize the primordial outcome of multiple star formation and the extent of the brown dwarf desert. Our survey identified 16 new binary companions to primary stars with masses of 0.25-2.5M_{sun}_, raising the total number of binary pairs (including components of high-order multiples) with separations of 3-5000AU to 90. We find that ~2/3-3/4 of all Taurus members are multiple systems of two or more stars, while the other ~1/4-1/3 appear to have formed as single stars; the distribution of high-order multiplicity suggests that fragmentation into a wide binary has no impact on the subsequent probability that either component will fragment again. The separation distribution for solar-type stars (0.7-2.5M_{sun}_) is nearly log-flat over separations of 3-5000AU, but lower-mass stars (0.25-0.7M_{sun}_) show a paucity of binary companions with separations of >~200AU. Across this full mass range, companion masses are well described with a linear-flat function; all system mass ratios (q=M_B_/M_A_) are equally probable, apparently including substellar companions. Our results are broadly consistent with the two expected modes of binary formation (free-fall fragmentation on large scales and disk fragmentation on small scales), but the distributions provide some clues as to the epochs at which the companions are likely to form.
- ID:
- ivo://CDS.VizieR/J/AJ/155/160
- Title:
- Multiple systems:relative positions and residuals
- Short Name:
- J/AJ/155/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer component. Such systems could be formed either sequentially (inside-out) by disk fragmentation with subsequent accretion and migration, or by a cascade hierarchical fragmentation of a rotating cloud. Orbits of the outer and inner subsystems are computed or updated in four such hierarchies: LHS 1070 (GJ 2005, periods 77.6 and 17.25 years), HIP 9497 (80 and 14.4 years), HIP 25240 (1200 and 47.0 years), and HIP 78842 (131 and 10.5 years).
- ID:
- ivo://CDS.VizieR/J/AJ/154/184
- Title:
- Multiplicity of RV exoplanet host stars
- Short Name:
- J/AJ/154/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Given the frequency of stellar multiplicity in the solar neighborhood, it is important to study the impacts this can have on exoplanet properties and orbital dynamics. There have been numerous imaging survey projects established to detect possible low-mass stellar companions to exoplanet host stars. Here, we provide the results from a systematic speckle imaging survey of known exoplanet host stars. In total, 71 stars were observed at 692 and 880 nm bands using the Differential Speckle Survey Instrument at the Gemini-north Observatory. Our results show that all but two of the stars included in this sample have no evidence of stellar companions with luminosities down to the detection and projected separation limits of our instrumentation. The mass-luminosity relationship is used to estimate the maximum mass a stellar companion can have without being detected. These results are used to discuss the potential for further radial velocity follow-up and interpretation of companion signals.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/85
- Title:
- Multi-wavelength analysis of the MIR bubble N37
- Short Name:
- J/ApJ/833/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a multi-wavelength analysis of a mid-infrared (MIR) bubble N37 and its surrounding environment. The selected 15'x15' area around the bubble contains two molecular clouds (N37 cloud; V_lsr_~37-43km/s, and C25.29+0.31; V_lsr_~43-48km/s) along the line of sight. A total of seven OB stars are identified toward the bubble N37 using photometric criteria, and two of them are spectroscopically confirmed as O9V and B0V stars. The spectro-photometric distances of these two sources confirm their physical association with the bubble. The O9V star appears to be the primary ionizing source of the region, which is also in agreement with the desired Lyman continuum flux analysis estimated from the 20cm data. The presence of the expanding HII region is revealed in the N37 cloud, which could be responsible for the MIR bubble. Using the ^13^CO line data and photometric data, several cold molecular condensations as well as clusters of young stellar objects (YSOs) are identified in the N37 cloud, revealing ongoing star formation (SF) activities. However, the analysis of ages of YSOs and the dynamical age of the HII region do not support the origin of SF due to the influence of OB stars. The position-velocity analysis of ^13^CO data reveals that two molecular clouds are interconnected by a bridge-like structure, favoring the onset of a cloud-cloud collision process. The SF activities (i.e., the formation of YSO clusters and OB stars) in the N37 cloud are possibly influenced by the cloud-cloud collision.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A141
- Title:
- MUSE-Wide Survey DR1 catalog
- Short Name:
- J/A+A/624/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. The final survey will cover 100x1arcmin^2^ MUSE fields. Each MUSE-Wide pointing has a depth of one hour and hence targets more extreme and more luminous objects over ten times the area of the MUSE-Deep fields (Bacon et al., 2017A&A...608A...1B). The legacy value of MUSE-Wide lies in providing "spectroscopy of everything" without photometric pre-selection. We describe the data reduction, post-processing and PSF characterization of the first 44 CANDELS/GOODS-S MUSE-Wide pointings released with this publication. Using a 3D matched filtering approach we detect 1602 emission line sources, including 479 Lyman-{alpha} (Lya) emitting galaxies with redshifts 2.9<~z<~6.3. We cross-matched the emission line sources to existing photometric catalogs, finding almost complete agreement in redshifts (photometric and spectroscopic) and stellar masses for our low redshift (z<1.5) emitters. At high redshift, we only find ~55% matches to photometric catalogs. We encounter a higher outlier rate and a systematic offset of {Delta}z~=0.2 when comparing our MUSE redshifts with photometric redshifts from the literature. Cross-matching the emission line sources with X-ray catalogs from the Chandra Deep Field South, we find 127 matches, mostly in agreement with the literature redshifts, including ten objects with no prior spectroscopic identification. Stacking X-ray images centered on our Lya emitters yields no signal; the Lya population is not dominated by even low luminosity AGN. Other cross-matches of our emission-line catalog to radio and submm data, yielded far lower numbers of matches, most of which already were covered by the X-ray catalog. A total of 9205 photometrically selected objects from the CANDELS survey lie in the MUSE-Wide footprint, of which we provide optimally extracted 1D spectra. We are able to determine the spectroscopic redshift of 98% of 772 photometrically selected galaxies brighter than 24th F775W magnitude. All the data in the first data release - datacubes, catalogs, extracted spectra, maps - are available on the website https://musewide.aip.de.
- ID:
- ivo://CDS.VizieR/III/254
- Title:
- 2nd Cat. of Radial Velocities with Astrometric Data
- Short Name:
- III/254
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of radial velocities of Galactic stars with high precision astrometric data, 2nd version (CRVAD-2), is the result of a merging of star lists from the All-Sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5, Cat. I/280) with the General Catalogue of Radial Velocities (GCRV, Cat. III/213) and with other recently published radial velocity lists and catalogues. Cross identification of objects was carried out with help of coordinate, magnitude, colour and/or spectral type criteria. Data from the Catalogue of Components of Double and Multiple Stars (CCDM, Cat. I/274) were taken into account for the identification of multiple system components. Altogether 54907 stars from the ASCC-2.5 were identified with 51762 stars from the RV source catalogues, 3085 stars have secondary components and 30 stars have 3rd components in multiple systems. The CRVAD-2 includes accurate J2000 equatorial coordinates, proper motions and trigonometric parallaxes in the Hipparcos system, Johnson's BV photometric data, spectral types, radial velocities, multiplicity and variability flags. Stars are sorted in the order of increasing right ascension J2000. This catalogue supersedes the previous version numbered <III/239>.
- ID:
- ivo://CDS.VizieR/J/AJ/153/25
- Title:
- Near-infrared observations of 84 KOI systems
- Short Name:
- J/AJ/153/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine probabilities of physical association for stars in blended Kepler Objects of Interest (KOIs), and find that 14.5%_-3.4%_^+3.8%^ of companions within ~4'' are consistent with being physically unassociated with their primary. This produces a better understanding of potential false positives in the Kepler catalog and will guide models of planet formation in binary systems. Physical association is determined through two methods of calculating multi-band photometric parallax using visible and near-infrared adaptive optics observations of 84 KOI systems with 104 contaminating companions within ~4''. We find no evidence that KOI companions with separations of less than 1'' are more likely to be physically associated than KOI companions generally. We also reinterpret transit depths for 94 planet candidates, and calculate that 2.6%+/-0.4% of transits have R>15R_{oplus}_, which is consistent with prior modeling work.
- ID:
- ivo://CDS.VizieR/J/ApJ/637/1067
- Title:
- Near-IR spectral classification of T dwarfs
- Short Name:
- J/ApJ/637/1067
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A revised near-infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser and coworkers (2002ApJ...564..421B) and Geballe and coworkers (2002ApJ...564..466G), and defined following the precepts of the MK process. Drawing from two large spectroscopic libraries of T dwarfs identified largely in the Sloan Digital Sky Survey and the Two Micron All Sky Survey, nine primary spectral standards and five alternate standards spanning spectral types T0-T8 are identified that match criteria of spectral character, brightness, absence of a resolved companion, and accessibility from both the Northern and Southern Hemispheres.
- ID:
- ivo://CDS.VizieR/J/AJ/144/99
- Title:
- Near-IR spectroscopy of 36 late M dwarfs
- Short Name:
- J/AJ/144/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of 36 late M dwarfs obtained with the KeckII/NIRSPEC in the J band at a resolution of ~20000. We have measured projected rotational velocities, absolute radial velocities, and pseudo-equivalent widths of atomic lines. Twelve of our targets did not have previous measurements in the literature. For the other 24 targets, we confirm previously reported measurements. We find that 13 stars from our sample have vsini below our measurement threshold (12km/s) whereas four of our targets are fast rotators (vsini>30km/s). As fast rotation causes spectral features to be washed out, stars with low projected rotational velocities are sought for radial velocity surveys. At our intermediate spectral resolution, we have confirmed the identification of neutral atomic lines reported in McLean et al. We also calculated pseudo-equivalent widths of 12 atomic lines. Our results confirm that the pseudo-equivalent width of KI lines is strongly dependent on spectral types. We observe that the pseudo-equivalent width of FeI and MnI lines remains fairly constant with later spectral type. We suggest that these lines are particularly suitable for deriving metallicities for late M dwarfs.
