- ID:
- ivo://CDS.VizieR/J/AJ/129/413
- Title:
- New high proper motion stars (-90<DE< -47)
- Short Name:
- J/AJ/129/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 141 new high proper motion systems ({mu}>=0.4"/yr) in the southern sky (DE=-90 to -47{deg}) brighter than UKST plate R_59F_=16.5 via our SuperCOSMOS-RECONS search. When combined with the nine systems having {mu}>=1.0"/yr and/or late spectral type from the initial phases of this effort, we find that 73 of the 150 total systems are moving faster than 0.5"/yr and are therefore new members of the classic Luyten Half-Second sample. These constitute a 21% increase in the sample of stars with {mu}>=0.5"/yr in the declination region searched, thereby comprising an important addition to this long-neglected region of the sky. Distance estimates are provided for the entire sample, based on a combination of photographic plate magnitudes and Two Micron All Sky Survey photometry, using the relations recently presented by Hambly et al. for the presumed main-sequence stars. Three systems are anticipated to be within 10pc, and an additional 15 are within 25pc. Nine of these 18 nearby systems have proper motions falling between 0.4"/yr and 0.6"/yr, hinting at a large population of nearby stars with fast, but not extremely high, proper motions that have not been thoroughly investigated.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/130/1658
- Title:
- New high proper motion stars (-47<{delta}<00)
- Short Name:
- J/AJ/130/1658
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 152 new high proper motion systems ({mu}>=0.4"/yr) in the southern sky ({delta}=-47{deg} to 00{deg}) brighter than UKST plate R_59F_=16.5 via our SuperCOSMOS-RECONS (SCR) search. This paper complements Paper XII (2005, Cat. <J/AJ/129/413>) in the Solar Neighborhood series, which covered the region from {delta}=-90{deg} to -47{deg} and discussed all 147 new systems from the southernmost phase of the search. Among the total of 299 systems from both papers, there are 148 (71 in Paper XII (2005, Cat. <J/AJ/129/413>), 77 in this paper) new systems moving faster than 0.5"/yr that are additions to the classic Luyten Half Second sample (1979, Cat. <I/87>). These constitute an 8% increase in the sample of all stellar systems with {mu}>=0.5"/yr in the southern sky.
1943. New hot subdwarf stars
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/3396
- Title:
- New hot subdwarf stars
- Short Name:
- J/MNRAS/457/3396
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) represents the adequate framework to handle the huge amount of information available and filter out data according to specific requirements. In this work, we applied a selection strategy to find new, uncatalogued hot subdwarfs making use of VO tools. We used large area catalogues like GALEX, Sloan Digital Sky Survey (SDSS), SuperCosmos and Two Micron All Sky Survey (2MASS) to retrieve photometric and astrometric information of stellar objects. To these objects, we applied colour and proper motion filters, together with an effective temperature cutoff, aimed at separating hot subdwarfs from other blue objects such as white dwarfs, cataclysmic variables or main-sequence OB stars. As a result, we obtained 437 new, uncatalogued hot subdwarf candidates. Based on previous results, we expect our procedure to have an overall efficiency of at least 80 per cent. Visual inspection of the 68 candidates with SDSS spectrum showed that 65 can be classified as hot subdwarfs: 5 sdOs, 25 sdOBs and 35 sdBs. This success rate above 95 per cent proves the robustness and efficiency of our methodology. The spectral energy distribution of 45 per cent of the subdwarf candidates showed infrared excesses, a signature of their probable binary nature. The stellar companions of the binary systems so detected are expected to be late-type main-sequence stars. A detailed determination of temperatures and spectral classification of the cool companions will be presented in a forthcoming work.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/489
- Title:
- New infrared carbon stars in IRAS PSC
- Short Name:
- J/A+AS/122/489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new results of a search for infrared carbon stars (IRCS) based on the combination of IRAS and near infrared colours. A sample of 207 stars with IRAS colours that characterize IRCS is selected and measured in the JHKL photometric bands. Using a [12-25] vs. K-L colour diagram, 20 new IRCS candidates are proposed. Medium resolution spectra in the ~6000-9000{AA} range of 8 of these candidates confirm their carbon rich nature. In addition we propose a few stars with LRS class "4n" as oxygen-rich candidates, and a few stars with LRS classes "0n" and "1n" as carbon-rich.
- ID:
- ivo://CDS.VizieR/J/AJ/153/218
- Title:
- New IR photometric study of Ap and Am stars
- Short Name:
- J/AJ/153/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, 426 well known confirmed Ap and Am stars are photometrically studied in the infrared. The 2MASS, Wide-field Infrared Survey Explorer (WISE), and IRAS data are employed to make analyses. The results in this paper have shown that in the 1-3 {mu}m region over 90% Ap and Am stars have no or little infrared excesses, and infrared radiations in the near-infrared from these stars are probably dominated by the free-free emissions. It is also shown that in the 3-12 {mu}m region, the majority of Ap stars and Am stars have very similar behavior, i.e., in the W1-W2 (3.4-4.6 {mu}m) region, over half of Ap and Am stars have clear infrared excesses, which are possibly due to the binarity, the multiplicity, and/or the debris disk, but in the W2-W3 (4.6-12 {mu}m) region they have no or little infrared excess. In addition, in the 12-22 {mu}m region, some of Ap stars and Am stars show the infrared excesses and infrared radiations for these Ap and Am stars are probably due to the free-free emissions. In addition, it is seen that the probability of being the binarity, the multiplicity and/or the debris disk for Am stars is much higher than that for Ap stars. Furthermore, it can be seen that, in general, no relations can be found between infrared colors and spectral types either for Ap stars or for Am stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/684/635
- Title:
- New low-mass eclipsing binary from SDSS-II
- Short Name:
- J/ApJ/684/635
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of a new low-mass, double-lined eclipsing binary system discovered using repeat observations of the celestial equator from the Sloan Digital Sky Survey II. Using near-infrared photometry and optical spectroscopy we have measured the properties of this short-period [P=0.407037(14)days] system and its two components. We find the following parameters for the two components: M_1_=0.272+/-0.020M_{sun}_, R_1_=0.268+/-0.010R_{sun}_, M_2_=0.240+/-0.022M_{sun}_, R_2_=0.248+/-0.0090R_{sun}_, T_1_=3320+/-130K, and T_2_=3300+/-130K. The masses and radii of the two components of this system agree well with theoretical expectations based on models of low-mass stars, within the admittedly large errors.
- ID:
- ivo://CDS.VizieR/J/AJ/132/866
- Title:
- New M dwarfs in solar neighborhood
- Short Name:
- J/AJ/132/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a spectroscopic study of 1063 nearby active M dwarfs, selected by correlating the Two Micron All Sky Survey and ROSAT catalogs. We have derived the spectral types and estimated distances for all of our stars. The spectral types range between K5 and M6. Nearly half of our stars lie within 50pc. We have measured the equivalent width of the H{alpha} emission line. Our targets show an increase in chromospheric activity from early to midspectral types, with a peak in activity around M5. Using the count rate and hardness ratios obtained from the ROSAT catalog, we have derived the X-ray luminosities. Our stars display a "saturation-type" relation between the chromospheric and coronal activity. The relation is such that log(LX/Lbol) remains "saturated" at a value of approximately -3 for varying H{alpha} equivalent width. We have found 568 matches in the USNO-B catalog and have derived the tangential velocities for these stars. There is a slight trend of decreasing chromospheric activity with age, such that the stars with higher vtan have lower H{alpha} equivalent widths. The coronal emission, however, remains saturated at a value of log(LX/Lbol)~-3 for varying tangential velocities, suggesting that the coronal activity remains saturated with age. We do not find any break in the saturation-type relation at the spectral type at which stars become fully convective (~M3.5). Most of the stars in our sample show more coronal emission than the dMe stars in the Hyades and Praesepe and have v_tan_<40km/s, suggesting a young population.
- ID:
- ivo://CDS.VizieR/J/AJ/153/36
- Title:
- New minima timings and RVs for 3 eclipsing binaries
- Short Name:
- J/AJ/153/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eclipsing binaries remain crucial objects for our understanding of the universe. In particular, those that are components of multiple systems can help us solve the problem of the formation of these systems. Analysis of the radial velocities together with the light curve produced for the first time precise physical parameters of the components of the multiple systems V773 Cas, QS Aql, and BR Ind. Their visual orbits were also analyzed, which resulted in slightly improved orbital elements. What is typical for all these systems is that their most dominant source is the third distant component. The system V773 Cas consists of two similar G1-2V stars revolving in a circular orbit and a more distant component of the A3V type. Additionally, the improved value of parallax was calculated to be 17.6 mas. Analysis of QS Aql resulted in the following: the inner eclipsing pair is composed of B6V and F1V stars, and the third component is of about the B6 spectral type. The outer orbit has high eccentricity of about 0.95, and observations near its upcoming periastron passage between the years 2038 and 2040 are of high importance. Also, the parallax of the system was derived to be about 2.89 mas, moving the star much closer to the Sun than originally assumed. The system BR Ind was found to be a quadruple star consisting of two eclipsing K dwarfs orbiting each other with a period of 1.786 days; the distant component is a single-lined spectroscopic binary with an orbital period of about 6 days. Both pairs are moving around each other on their 148 year orbit.
- ID:
- ivo://CDS.VizieR/J/A+A/421/643
- Title:
- New nearby stars in the LEHPMS
- Short Name:
- J/A+A/421/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic search for new neighbourhood stars among the Liverpool-Edinburgh high proper motion survey which we cross-identified with the DENIS survey. Their high proper motions ensure that they are not giant stars. The distances are estimated using DENIS photometry and we found that 100 stars probably lie within 25 parsecs from the Sun. They are mostly M-dwarfs, and 10 are probably white dwarfs. This is the first distance estimate for 84 stars among them. 10 stars are estimated to be closer than 15 parsecs. In addition, one star, DENIS J2343155-241047, could also lie within 15pc if it belongs to the halo.
- ID:
- ivo://CDS.VizieR/J/AJ/134/252
- Title:
- New nearby white dwarf systems
- Short Name:
- J/AJ/134/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectra for 33 previously unclassified white dwarf systems brighter than V=17, primarily in the southern hemisphere. Of these new systems, 26 are DA, 4 are DC, 2 are DZ, and 1 is DQ. We suspect that three of these systems are unresolved double degenerates. We obtained VRI photometry for these 33 objects, as well as for 23 known white dwarf systems without trigonometric parallaxes, also primarily in the southern hemisphere. For the 56 objects, we converted the photometry values to fluxes and fit them to a spectral energy distribution using the spectroscopy to determine which model to use (i.e., pure hydrogen, pure helium, or metal-rich helium), resulting in estimates of Teff and distance.
