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1581. 35 DENIS late-M dwarfs between 10 and 30pc
ID:
ivo://CDS.VizieR/J/A+A/401/959
Title:
35 DENIS late-M dwarfs between 10 and 30pc
Short Name:
J/A+A/401/959
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper reports updated results on our systematic mining of the DENIS database (<B/denis>) for nearby very cool M-dwarfs (M6V-M8V, 2.0=<I-J=<3.0, photometric distance within 30pc), initiated by Phan-Bao et al. (2001, Cat. <J/A+A/380/590>, hereafter Paper I). We use M dwarfs with well measured parallaxes (HIP, GCTP,...) to calibrate the DENIS (M_I_, I-J) colour-luminosity relationship. The resulting distance error for single dwarfs is about 25%. Proper motions, as well as B and R magnitudes, were measured on archive Schmidt plates for those stars in the DENIS database that meet the photometric selection criteria. We then eliminate the giants by a Reduced Proper Motion cutoff, which is significantly more selective than a simple proper motion cutoff. It greatly reduces the selection bias against low tangential velocity stars, and results in a nearly complete sample. Here we present new data for 62 red dwarf candidates selected over 5700 square degrees in the DENIS database. 26 of those originate in the 2100 square degrees analysed in Paper I, with improved parameters here, and 36 were found in 3600 additional square degrees. 25 of those are new nearby dwarfs. In addition we cross-identified the NLTT and DENIS catalogues to find 15 similar stars, in parts of the sky not yet covered by the colour-selected search. We present distance and luminosity estimates for these 15 stars, 10 of which are newly recognized nearby dwarfs. A similar search in Paper I produced 4 red dwarf candidates, and we have thus up to now identified a total of 35 new nearby late-M dwarfs.
1582. 30 DENIS late-M dwarfs between 15 and 30pc
ID:
ivo://CDS.VizieR/J/A+A/380/590
Title:
30 DENIS late-M dwarfs between 15 and 30pc
Short Name:
J/A+A/380/590
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 30 new nearby (d<30pc) red dwarf candidates, with estimated spectral types M6 to M8. 26 were directly selected from the DENIS database (<B/denis>), and another 4 were first extracted from the LHS catalogue (<I/87>) and cross-identified with a DENIS counterpart. Their proper motions were measured on the MAMA measuring machine from plates spanning 13 to 48 years, and are larger than 0.1arcsec/yr, ruling out the possibility that they are giants. Their distances were estimated from the DENIS colours and IR colour-magnitude relations and range between 15 and 30pc.
1583. 32 DENIS nearby red dwarfs
ID:
ivo://CDS.VizieR/J/A+A/441/653
Title:
32 DENIS nearby red dwarfs
Short Name:
J/A+A/441/653
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectra of 36 nearby star candidates and 3 red giant candidates, identified in the DENIS database. 32 of the dwarf candidates are nearby red dwarfs, with spectral types from M5.5 to M8.5. Out of 11 targets with low proper motion (mu<0.1arcsec/yr) but a Reduced Proper Motion above an inclusive threshold, 9 are red dwarfs. The 4 contaminants are all reddened F-K main sequence stars, and could have been eliminated by checking for small well-known high latitude molecular clouds. These stars might be of interest as probes of interstellar absorption. For the red dwarfs we derive spectral types and spectroscopic distances, using a new calibration of the PC3 spectral index to absolute magnitudes in the I, J, H and K photometric bands. We confirm 2 new members of the 12 pc volume (2 new M8.5), and one M7.5 NLTT object closer than 10pc; and show that one quarter of the stars with photometric distances under 30pc have too small a proper motion for inclusion in the NLTT catalog.
1584. DENIS new nearby stars
ID:
ivo://CDS.VizieR/J/A+A/390/491
Title:
DENIS new nearby stars
Short Name:
J/A+A/390/491
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new nearby stars extracted from a proper motion catalogue and having a DENIS counterpart. Their distances and spectral type are estimated using the DENIS colours. 107 stars are within 50pc. 31 stars among them have previously measured distances. In addition, 40 stars may enter within the 50pc limit depending on which population they belong to. 6 stars among them have already measured distances. 5 objects, LHS5045, L225-57, LP831-45, LHS1767, and WT792, are probably closer than 15pc, with L225-57 at 9.5pc. Most of these stars are M-type while 4 stars are white dwarfs. 88 M-dwarfs are disc stars, 14 belong to the thick disc and 1 to the spheroid.
1585. Dense cores and YSOs in Lupus complex
ID:
ivo://CDS.VizieR/J/A+A/619/A52
Title:
Dense cores and YSOs in Lupus complex
Short Name:
J/A+A/619/A52
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the catalogue of the dense cores and YSOs/protostars of the Lupus I, Lupus III, and Lupus IV molecular clouds. Sources were extracted from the far-infrared photometric maps at 70, 160, 250, 350 and 500um acquired with the Spectral and Photometric Imaging Receiver (SPIRE) and the Photodetector Array Camera and Spectrometer (PACS) instruments onboard the Herschel Space Observatory, within the Herschel Gould Belt Survey project. A total of 532 dense cores, out of which 103 are presumably prestellar in nature, and 38 YSOs/protostars have been detected in the three clouds. The physical properties of the objects were derived by fitting their spectral energy distributions. Almost all the prestellar cores are associated with filaments against only about one third of the unbound cores and YSOs/ protostars. Prestellar core candidates are found even in filaments that are on average thermally sub-critical and over a background column density lower than that measured in other star forming regions so far. The core mass function of the prestellar cores peaks between 0.2 and 0.3 solar masses and it is compatible with the log-normal shape found in other regions. Herschel data reveal several, previously undetected, protostars and new candidates of Class 0 and Class II with transitional disks. We estimate the evolutionary status of the YSOs/protostars using two independent indicators: the {alpha} index and the fitting of the spectral energy distribution from near- to far-infrared wavelengths. For 70% of the objects, the evolutionary stages derived with the two methods are in agreement.
1586. Dense cores in Taurus L1495 cloud
ID:
ivo://CDS.VizieR/J/MNRAS/459/342
Title:
Dense cores in Taurus L1495 cloud
Short Name:
J/MNRAS/459/342
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalogue of dense cores in a ~4{deg}x2{deg} field of the Taurus star-forming region, inclusive of the L1495 cloud, derived from Herschel SPIRE and PACS observations in the 70{mu}m, 160{mu}m, 250{mu}m, 350{mu}m, and 500{mu}m continuum bands. Estimates of mean dust temperature and total mass are derived using modified blackbody fits to the spectral energy distributions. We detect 525 starless cores of which ~10-20 per cent are gravitationally bound and therefore presumably prestellar. Our census of unbound objects is ~85 per cent complete for M>0.015M_{sun}_ in low-density regions (A_V_<~5mag), while the bound (prestellar) subset is ~85 per cent complete for M>0.1M_{sun}_ overall. The prestellar core mass function (CMF) is consistent with lognormal form, resembling the stellar system initial mass function, as has been reported previously. All of the inferred prestellar cores lie on filamentary structures whose column densities exceed the expected threshold for filamentary collapse, in agreement with previous reports. Unlike the prestellar CMF, the unbound starless CMF is not lognormal, but instead is consistent with a power-law form below 0.3M_{sun}_ and shows no evidence for a low-mass turnover. It resembles previously reported mass distributions for CO clumps at low masses (M<~0.3M_{sun}_). The volume density PDF, however, is accurately lognormal except at high densities. It is consistent with the effects of self-gravity on magnetized supersonic turbulence. The only significant deviation from lognormality is a high-density tail which can be attributed unambiguously to prestellar cores.
1587. Deprojection of the r^1/4^ law tables
ID:
ivo://CDS.VizieR/J/AJ/81/807
Title:
Deprojection of the r^1/4^ law tables
Short Name:
J/AJ/81/807
Date:
21 Oct 2021
Publisher:
CDS
Description:
A spherical galaxy with reduced surface brightness, J=B({alpha})/B_e_, obeying the r^1/4^ law, logJ=-3.3307 ({alpha}^1/4^-1), where {alpha} is the reduced radius, {alpha}=r/r_e_ (r_e_ is the effective radius), is deprojected to find the corresponding space density, mass, mean density, force, potential, escape velocity, and potential energy at each point in the galaxy. Numerical tabulations to five significant figures are given for 124 points in the range 10^-6^<=R/r_e_<=260. In addition the projected surface brightness B({alpha}) and integrated luminosity within {alpha} are tabulated for the range 10^-6^<={alpha}=r/r_e_<=260. Conversion factors to cgs units and to M_{sun}_, pc, km/s, L_{sun}_ units are given. Asymptotic expansions for the space density {rho}(s) in the ranges s=<10^-4^ and s>=10^-1^ are derived, and it is demonstrated that the projection of the expansion for s<=10^-1^ is almost indistinguishable from the r^1/4^ law itself, apart from a small excess of luminosity in the central regions. Formulae and numerical tables of the luminosity distribution are given for use in galaxy photometry. Relations between the total galactic mass M_T_, the effective radius r_e_, the velocity dispersion {sigma}_v_, the central density {rho}_c_ and the mass M_N_ and radius R_N_ of the nucleus are derived. Here the "nucleus" is defined as the region within which stars having a velocity equal to the mean velocity dispersion in space, {sigma}_v_.
1588. DES Y3 substellar LT and M catalogs
ID:
ivo://CDS.VizieR/J/MNRAS/489/5301
Title:
DES Y3 substellar LT and M catalogs
Short Name:
J/MNRAS/489/5301
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present a catalogue of 11745 brown dwarfs with spectral types ranging from L0 to T9, photometrically classified using data from the Dark Energy Survey (DES) year 3 release matched to the Vista Hemisphere Survey (VHS) DR3 and Wide-field Infrared Survey Explorer (WISE) data, covering ~2400deg^2^ up to i_AB_=22. The classification method follows the same photo-type method previously applied to SDSS-UKIDSS-WISE data. The most significant difference comes from the use of DES data instead of SDSS, which allow us to classify almost an order of magnitude more brown dwarfs than any previous search and reaching distances beyond 400 parsecs for the earliest types. Next, we also present and validate the GalmodBD simulation, which produces brown dwarf number counts as a function of structural parameters with realistic photometric properties of a given survey. We use this simulation to estimate the completeness and purity of our photometric LT catalogue down to i_AB_=22, as well as to compare to the observed number of LT types. We put constraints on the thin disk scale height for the early L (L0-L3) population to be around 450 parsecs, in agreement with previous findings. For completeness, we also publish in a separate table a catalogue of 20863 M dwarfs that passed our colour cut with spectral types greater than M6. Both the LT and the late M catalogues are found at https://des.ncsa.illinois.edu/releases/other/y3-mlt.
1589. Detached eclipsing binaries MITSuME photometry
ID:
ivo://CDS.VizieR/J/A+A/622/A114
Title:
Detached eclipsing binaries MITSuME photometry
Short Name:
J/A+A/622/A114
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results of the combined photometric and spectroscopic analysis of three detached eclipsing binaries (DEBs), the secondary components of which are not visible or are very hard to identify in the optical spectra - ASAS J052743-0359.7, ASAS J065134-2211.5, and ASAS J073507-0905.7. The first one is the known visual binary ADS~4022, and we found that it is a quadruple system composed of two spectroscopic binaries, one of which shows eclipses.
1590. Detached eclipsing binaries with Gaia parallaxes
ID:
ivo://CDS.VizieR/J/ApJ/872/85
Title:
Detached eclipsing binaries with Gaia parallaxes
Short Name:
J/ApJ/872/85
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using a sample of 81 Galactic, detached eclipsing binary stars we investigated the global zero-point shift of their parallaxes with the Gaia Data Release 2 (DR2) parallaxes. The stars in the sample lay in a distance range of 0.04-2kpc from the Sun. The photometric parallaxes {omega}_Phot_ of the eclipsing binaries were determined by applying a number of empirical surface brightness-color (SBC) relations calibrated on optical-infrared colors. For each SBC relation we calculated the individual differences d{varpi}_i_=({varpi}_Gaia_-{varpi}_Phot_)_i_ and then we calculated unweighted and weighted means. As the sample covers the whole sky we interpret the weighted means as the global shifts of the Gaia DR2 parallaxes with respect to our eclipsing binary sample. Depending on the choice of the SBC relation the shifts vary from -0.094 to -0.025mas. The weighted mean of the zero-point shift from all colors and calibrations used is d{omega}=-0.054+/-0.024mas. However, the SBC relations based on (B-K) and (V-K) colors, which are the least reddening dependent and have the lowest intrinsic dispersions, give a zero-point shift of d{omega}=-0.031+/-0.011mas in full agreement with results obtained by Lindegren+ (2018A&A...616A...2L) and Arenou+ (2018A&A...616A..17A). Our result confirms the global shift of Gaia DR2 parallaxes of d{omega}=-0.029mas reported by the Gaia team, but we do not confirm the larger zero-point shift reported by a number of follow-up papers.