New BV light curves of the short-period eclipsing binary system DD Mon have been obtained. Light-curve variability is seen in both B and V bands as compared with the light curves obtained in 1986 by Yamasaki et al. (1990AJ.....99.1218Y). The light curves are analyzed by using Wilson-Devinney's synthetic light-curve program, and the present photometric solution reveals that DD Mon is a near-contact binary with the secondary component filling the Roche lobe. Combined with Yamasaki et al.'s (1990AJ.....99.1218Y) spectroscopic results, absolute quantities of DD Mon are derived: mass of the primary M_1_=1.05+/-0.08M_{sun}_, mass of the secondary M_2_=0.47+/-0.04M_{sun}_, radius of the primary R_1_=1.36+/-0.04R_{sun}_, radius of the secondary R_2_=1.03+/-0.03R_{sun}_. These results show that the components of DD Mon have evolved away from the ZAMS and through a mass-transfer process to the present semi-detached state. The variation in shape of the light curve may be caused by the evolution of the system and the activity of dark spots.
This catalogue collects the DDO photometric data published in the astronomical literature until the end of 1988, and contains 8034 DDO measurements, concerning 6139 stars. The DDO 6-filter has the following peak wavelengths and widths: ------------------------ Filter Peak Width [nm] [nm] ------------------------ 35 346.0 38.3 38 381.5 33.0 41 416.6 8.3 42 425.7 7.3 45 451.7 7.6 48 488.6 18.6 51 (*) 513.0 13.4 ------------------------ (*) additional to DDO.
DDO Photometry and Radial Velocities at Galactic Poles
Short Name:
V/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalogue includes the DDO photometry and the radial velocities observed for the study of the kinematics and abundance gradients of G and K stars in the Galactic poles regions.
This paper describes the observations and gives the results of a series of observations of bright E-region stars (Cousins A.W.J. and Stoy R.H., 1962RGOB...49....3C) for use as zero point stars for DDO photometry in the southern hemisphere. The list comprises 45 stars, all brighter than V=6.0, and gives the colours in the instrumental system with internal s.e. +/-0.001mag and m_48_ with s.e. +/-0.002mag. The observed m_48_ is indistinguishable from McClure's system and has the same zero point (+/-0.002mag). The individual E-region zero points have been established with s.e. +/-0.001 relative to the instrumental system, but the colour equations (and zero point corrections) to transform the instrumental colours to McClure's system have still to be finalised. For a description of the DDO photometric system, see e.g. <GCPD/12>
Three dimensional interstellar extinction maps provide a powerful tool for stellar population analysis. However, until now, these 3D maps were rather limited by sensitivity and spatial resolution. We use data from the VISTA Variables in the Via Lactea survey together with the Besancon stellar population synthesis model of the Galaxy to determine interstellar extinction as a function of distance in the Galactic bulge covering -10<l<10 and -10<b<5. We adopted a recently developed method to calculate the colour excess. First we constructed the H-Ks vs. Ks and J-Ks vs. Ks colour-magnitude diagrams based on the VVV catalogues that matched 2MASS. Then, based on the temperature-colour relation for M giants and the distance-colour relations, we derived the extinction as a function of distance. The observed colours were shifted to match the intrinsic colours in the Besancon model as a function of distance iteratively. This created an extinction map with three dimensions: two spatial and one distance dimension along each line of sight towards the bulge. We present a 3D extinction map that covers the whole VVV area with a resolution of 6'x6', for J-Ks and H-Ks using distance bins of 0.5-1.0kpc. The high resolution and depth of the photometry allows us to derive extinction maps for a range of distances up to 10kpc and up to 30 magnitudes of extinction in AV (3.0mag in AKs). Integrated maps show the same dust features and consistent values as other 2D maps. We discuss the spatial distribution of dust features in the line of sight, which suggests that there is much material in front of the Galactic bar, specifically between 5-7kpc. We compare our dust extinction map with the high-resolution ^12^CO maps (NANTEN2) towards the Galactic bulge, where we find a good correlation between ^12^CO and A_V_. We determine the X factor by combining the CO map and our dust extinction map. Our derived average value X=2.5+/-0.47x10^20^/(cm^2^.K.km/s) is consistent with the canonical value of the Milky Way. The X-factor decreases with increasing extinction.
The Dearborn Survey is the result of a survey of faint red stars conducted at the Dearborn Observatory from about 1932 to 1947. It covers the declination range -4.5deg to +90deg (54% of the Sky), and consisted of over 1800 direct plates and spectrograms carrying single or multiple exposures varying from a second to 4 hours. The magnitudes in the catalog were obtained from direct plates mostly sensitive in the 0.55-0.64{mu}m wavelength region. The spectral types were obtained from objective-prism plates with red-sensitive emulsion, and were classified on the visibility of the TiO bands.
We present the re-calibrated and re-imaged fits-cubes of the second set of data from the DEATHSTAR project (DEtermining Accurate mass-loss rates for THermally pulsing AGB STARs, www.astro.uu.se/deathstar): the S-type stars. Fifteen S-type southern AGB stars were mapped in Bands 6 and 7 with the Atacama Compact Array (ACA). The generated beams have sizes of 4-8 and 3-6-arcseconds in Band 6 and 7, respectively. The rms noise level reached is typically 50-70 and 100-150mJy/beam in Band 6 and 7, respectively. The beam sizes and rms values for each source are listed in the paper together with the description of the reduction process, the analysis of the cubes and tentative line detections.
We present the re-calibrated and re-imaged fits-cubes of the first set of data from the DEATHSTAR project (DEtermining Accurate mass-loss rates for THermally pulsing AGB STARs, www.astro.uu.se/deathstar). Forty-two southern AGB stars, 21 carbon stars and 21 M-type stars, were mapped in Bands 6 and 7 with the Atacama Compact Array (ACA). Source selection, detected line emission, data calibration procedures etc. are described in detail in the paper. The beams are typically 4-8 and 3-5-arcseconds in Band 6 and 7, respectively. The rms noise level reached is typically 50-70 and 100-150mJy/beam in Band 6 and 7, respectively. More exact beam sizes and rms values for each source are listed in the paper together with tentative line detections.
Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their counterparts in the solar system are the asteroid and Edgeworth-Kuiper belts. The aim of this paper is to provide robust numbers for the incidence of debris discs around FGK stars in the solar neighbourhood. The full sample of 177 FGK stars with d>=20pc proposed for the DUst around NEarby Stars (DUNES) survey is presented. Herschel/PACS observations at 100 and 160{mu}m were obtained, and were complemented in some cases with data at 70{mu}m and at 250, 350, and 500{mu}m SPIRE photometry. The 123 objects observed by the DUNES collaboration were presented in a previous paper. The remaining 54 stars, shared with the Disc Emission via a Bias-free Reconnaissance in IR and Sub-mm (DEBRIS) consortium and observed by them, and the combined full sample are studied in this paper. The incidence of debris discs per spectral type is analysed and put into context together with other parameters of the sample, like metallicity, rotation and activity, and age. The subsample of 105 stars with d>=15pc containing 23 F, 33 G, and 49 K stars is complete for F stars, almost complete for G stars, and contains a substantial number of K stars from which we draw solid conclusions on objects of this spectral type. The incidence rates of debris discs per spectral type are 0.26^+0.21^_-0.14_ (6 objects with excesses out of 23 F stars), 0.21^+0.17^_-0.11_ (7 out of 33 G stars), and 0.20^0.14^_-0.09_ (10 out of 49 K stars); the fraction for all three spectral types together is 0.22^+0.08^_-0.07_ (23 out of 105 stars). The uncertainties correspond to a 95% confidence level. The medians of the upper limits of L_dust_/L* for each spectral type are 7.8x10^-7^ (F), 1.4x10^-6^ (G), and 2.2x10^-6^ (K); the lowest values are around 4.0x10^-7^. The incidence of debris discs is similar for active (young) and inactive (old) stars. The fractional luminosity tends to drop with increasing age, as expected from collisional erosion of the debris belts.
Dwarf stars with debris discs and planets appear to be excellent laboratories to study the core accretion theory of planets formation. These systems are however, insufficiently studied. In this paper we present the main metallicity and lithium abundance properties of these stars together with stars with only debris discs and stars with only planets. Stars without detected planets nor discs are also considered. The analysed sample is formed by main-sequence FGK field single stars. Apart from the basic stellar parameters, we include the use of dusty discs masses. The main results show for the first time that the dust mass of debris disc stars with planets correlate with metallicity. We confirm that these disc dust masses are related to their central stellar masses. Separately, the masses of stars and those of planets also correlate with metallicity. We conclude that two conditions are necessary to form giant planets: to have a sufficient metallicity and also a sufficient protoplanetary mass of gas and dust. The debris discs masses of stars without giant planets do not correlate with metallicity, because they do not fulfil these two conditions. Concerning lithium, by adopting a stellar model for lithium depletion based on a strong interaction between the star and a protoplanetary disc, we found that in agreement with the model predictions, observations indicate that the main lithium depletion occurs during this initial protoplanetary evolution stage. We show that the ultimately lithium depletion is independent of the presence or absence of planets and appears to be only age dependent.