- ID:
- ivo://CDS.VizieR/J/ApJS/234/25
- Title:
- Vanadium transitions in the spectrum of Arcturus
- Short Name:
- J/ApJS/234/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive a new abundance for vanadium in the bright, mildly metal-poor red giant Arcturus. This star has an excellent high-resolution spectral atlas and well-understood atmospheric parameters, and it displays a rich set of neutral vanadium lines that are available for abundance extraction. We employ a newly recorded set of laboratory FTS spectra to investigate any potential discrepancies in previously reported V I log(gf) values near 900nm. These new spectra support our earlier laboratory transition data and the calibration method utilized in that study. We then perform a synthetic spectrum analysis of weak V I features in Arcturus, deriving log{epsilon}(V)=3.54+/-0.01 ({sigma}=0.04) from 55 lines. There are no significant abundance trends with wavelength, line strength, or lower excitation energy.
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- ID:
- ivo://CDS.VizieR/J/ApJS/238/19
- Title:
- VANDAM IV. Free-free emission from protostars
- Short Name:
- J/ApJS/238/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Emission from protostars at centimeter radio wavelengths has been shown to trace the free-free emission arising from ionizing shocks as a result of jets and outflows driven by protostars. Therefore, measuring properties of protostars at radio frequencies can provide valuable insights into the nature of their outflows and jets. We present a C-band (4.1 and 6.4cm) survey of all known protostars (Class0 and ClassI) in Perseus as part of the VLA Nascent Disk and Multiplicity (VANDAM) Survey. We examine the known correlations between radio flux density and protostellar parameters, such as bolometric luminosity and outflow force, for our sample. We also investigate the relationship between radio flux density and far-infrared line luminosities from Herschel. We show that free-free emission most likely originates from J-type shocks; however, the large scatter indicates that those two types of emission probe different time and spatial scales. Using C-band fluxes, we removed an estimation of free-free contamination from the corresponding Ka- band (9mm) flux densities that primarily probe dust emission from embedded disks. We find that the compact (<1") dust emission is lower for Class I sources (median dust mass 96M_{Earth}_) relative to Class 0 (248M_{Earth}_), but several times higher than in Class II (5-15M_{Earth}_). If this compact dust emission is tracing primarily the embedded disk, as is likely for many sources, this result provides evidence of decreasing disk masses with protostellar evolution, with sufficient mass for forming giant planet cores primarily at early times.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/130
- Title:
- VANDAM survey of Orion protostars. II.
- Short Name:
- J/ApJ/890/130
- Date:
- 07 Mar 2022 13:26:15
- Publisher:
- CDS
- Description:
- We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87mm at a resolution of ~0.1" (40au), including observations with the Very Large Array at 9mm toward 148 protostars at a resolution of ~0.08" (32au). This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are 44.9_-3.4_^+5.8^, 37.0_-3.0_^+4.9^, and 28.5_-2.3_^+3.7^au, respectively, and the mean protostellar dust disk masses are 25.9_-4.0_^+7.7^, 14.9_-2.2_^+3.8^, 11.6_-1.9_^+3.5^M_{Earth}_, respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87mm continuum sources plus 42 nondetections) have disk radii greater than 50au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
- ID:
- ivo://CDS.VizieR/J/AJ/158/95
- Title:
- V348 And and V572 Per: heliocentric minima and RVs
- Short Name:
- J/AJ/158/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The eclipsing binaries are still important objects for our understanding of the universe. Especially these ones located within the more complex multiple systems can help us solving the problem of their origin and subsequent evolution of these higher order multiples. Photometry and spectroscopy spanning over more than 25 yr were used for the first complete analysis of the two bright triple systems, namely V348 And and V572 Per. The light curves in photometric filters were combined together with the radial velocities and analyzed simultaneously, yielding the precise physical parameters of the eclipsing components of these multiple systems. The system V348 And consists of two eclipsing components with its orbital period of about 27.7 days. The system is a very detached one, and both eclipses are rather narrow, lasting only about 0.016 of its period. The visual orbit of the wide pair has the period of about 87 yr. All three components of the system are probably of B8-9 spectral type, and the parallax of the system was slightly shifted to the value of 2.92 mas. On the other hand, the system V572 Per shows apsidal motion of its inner orbit, the orbital period being of about 1.2 days, while the apsidal motion of about 48 yr. The components are of A and F spectral types, while the motion with the third component around a common barycenter is only negligible. According to our modeling, this system is not a member of open cluster Alpha Persei.
- ID:
- ivo://CDS.VizieR/V/151
- Title:
- VANDELS High-Redshift Galaxy Evolution
- Short Name:
- V/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- VANDELS is a new ESO spectroscopic Public Survey targeting the high-redshift Universe. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the survey is obtaining ultra-deep optical spectroscopy of around 2100 galaxies in the redshift interval 1.0<z<7.0, with 85% of its targets selected to be at z>=3. The fundamental aim of the survey is to provide the high signal-to-noise spectra necessary to measure key physical properties such as stellar population ages, metallicities and outflow velocities from detailed absorption-line studies. By targeting two extragalactic survey fields with superb multi-wavelength imaging data, VANDELS will produce a unique legacy dataset for exploring the physics underpinning high-redshift galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/416/811
- Title:
- V and R CCD photometry of visual binaries
- Short Name:
- J/A+A/416/811
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 429 CCD measurements of relative positions and magnitude differences in V and R photometric bands for 165 visual double and multiple stars are given. CCD frames were taken at the 1.52m Spanish telescope of the Spanish-German Center of Astronomy at Calar Alto (Almeria, Spain). During the reduction process a "Tepui" function was used as the PSF function.
- ID:
- ivo://CDS.VizieR/J/AJ/159/21
- Title:
- V and Rc light curves of medium-bright PPNe
- Short Name:
- J/AJ/159/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 10 years of new photometric monitoring of the light variability of five evolved stars with strong mid-infrared emission from surrounding dust. Three are known carbon-rich proto-planetary nebulae (PPNe) with F-G spectral types; the nature of the other two was previously unknown. For the three PPNe, we determine or refine the pulsation periods of IRAS04296+3429 (71 days), 06530-0213 (80 days), and 23304+6147 (84 days). A secondary period was found for each, with a period ratio P_2_/P_1_ of 0.9. The light variations are small, 0.1-0.2mag. These are similar to values found in other PPNe. The other two are found to be giant stars. IRAS09296+1159 pulsates with a period of only 47 days but reaches pulsational light variations of 0.5mag. Supplemental spectroscopy reveals the spectrum of a CH carbon star. IRAS08359-1644 is a G1III star that does not display pulsational variability; rather, it shows nonperiodic decreases of brightness of up to 0.5mag over this 10 year interval. These drops in brightness are reminiscent of the light curves of R Corona Borealis variables, but with much smaller decreases in brightness and are likely due to transient dust obscuration. Its spectral energy distribution is very similar to that of the unusual oxygen-rich giant star HDE233517, which possesses mid-infrared hydrocarbon emission features. These two non-PPNe turn out to be members of the rare group of giant stars with large mid-infrared excesses due to dust, objects which presumably have interesting evolutionary histories.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/2750
- Title:
- V and R lightcurves of BL Lac object PKS 0537-441
- Short Name:
- J/MNRAS/449/2750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the colour indices V-R of BL Lacertae object PKS 0537-441 on the basis of the photometric data monitored by the Rapid Eye Mounting (REM) telescope located at the ESO Cerro La Silla observatory (Chile). Nearly 700 quasi-simultaneous data groups were collected during the period from 2004 to 2010. Our colour analysis shows the existence of at least two variability mechanisms: one is the long-term chromatic mechanism in which the variation traces a 0.04+/-0.01 slope in the V-R versus V plot, the other is the chromatic mechanism implying the spectral changes during the flares and on intraday time-scales. A general bluer-when-brighter trend is confirmed in both ascent and descent states during the flares and in the 2010 February flare interval, while a much stronger bluer-when-brighter chromatism is observed in both faint and bright states on intraday time-scales. The discrete correlation function analysis reveals the existence of a time-lag of 13^+5.8^_-1.2_ d between colour indices and magnitudes during the period MJD 54404-54453, whereas no measurable time-lag during other periods is found. Our results suggest that geometric effects may be responsible for the long-term achromatic mechanism, while the intrinsic shock-in-jet mechanism may produce the chromatic variability during the flares and on intraday time-scales.
- ID:
- ivo://CDS.VizieR/J/A+A/403/637
- Title:
- V and R light curves of GSC 3822-1056
- Short Name:
- J/A+A/403/637
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we present the first Johnson-Cousins VR_C_ light curves of the over-contact binary star GSC 3822-1056. A period study and the light curve solution are also given. An extremely high rate of period increase +11.6sec/century was found. The origin of this period change can be: (i) partly covered light-time effect due to the orbital motion around the mass center of a possible third body; (ii) mass transfer between the components. The light curve was solved by the 1998 Wilson-Devinney Code. We examined the light curve with and without third light. Both solutions yielded a contact configuration with high temperature difference between the components. Despite the high degree of the contact (f=0.57), the temperature difference between the components {Delta}T=T_primary_-T_secondary_=1045K. The high mass-ratio of the system and its other unusual properties suggest that GSC 3822-1056 may be a recently formed contact binary.
- ID:
- ivo://CDS.VizieR/J/other/CoSka/40.19
- Title:
- V466 And UBV(RI)c light curves
- Short Name:
- J/other/CoSka/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the UBV(RI)C photometry of a new dwarf nova V466 And, discovered during its superoutburst on Sept. 1.6, 2008 and classified as a WZ Sge-type object. In the first 11 days of the superoutburst, the early superhumps with the period of 0.056383d were found. In days 13-23 of the superoutburst, the ordinary superhumps with the period of 0.05713d were exposed. They were replaced by late superhumps with the period of 0.056d in days 24-33 of the superoutburst. After one month, the dwarf nova returned to its pre-outburst state. A list of known WZ Sge-type dwarf novae, including suspected ones, is presented. We determined a mean value of superhump period excess for WZ Sge-type objects as {epsilon}=0.019+/-0.003. The multicolour photometry of the field stars enables us to conclude that there is no appreciable interstellar extinction in the direction of V466 And.
