- ID:
- ivo://CDS.VizieR/J/AJ/155/265
- Title:
- The solar neighborhood. XLIV. RECONS discoveries
- Short Name:
- J/AJ/155/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the 44 systems discovered to be within 10 pc of the Sun by the RECONS team, primarily via the long-term astrometry program at the CTIO/SMARTS 0.9 m that began in 1999. The systems-including 41 with red dwarf primaries, 2 white dwarfs, and 1 brown dwarf-have trigonometric parallaxes greater than 100 mas, with errors of 0.4-2.4 mas in all but one case. We provide updated astrometric, photometric (VRIJHK magnitudes), spectral type, and multiplicity information here. Among these are 14 systems that are new entries to the 10 pc sample, including the first parallaxes for 9 systems and new values for 5 systems that had previous parallaxes with errors greater than 10 mas or values placing them beyond 10 pc. We also provide new data for 22 systems known to lie within 10 pc and 9 systems reported to be closer than that horizon but for which new parallaxes place them further away, bringing the total to 75 systems. The 44 systems added by RECONS comprise one of every 7 systems known within 10 pc. We illustrate the evolution of the 10 pc sample from the 191 systems known when the final Yale Parallax Catalog was published in 1995 to the 317 systems known today. Even so close to the Sun, additional discoveries of white, red, and brown dwarfs are possible, both as primaries and secondaries, although we estimate that at least 90% of the stellar systems closer than 10 pc have now been identified.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/149/127
- Title:
- The SOS project. IV. NGC 1624 and NGC 1931
- Short Name:
- J/AJ/149/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young open clusters located in the outer Galaxy provide us with an opportunity to study star formation activity in a different environment from the solar neighborhood. We present a UBVI and H{alpha} photometric study of the young open clusters NGC 1624 and NGC 1931 that are situated toward the Galactic anticenter. Various photometric diagrams are used to select the members of the clusters and to determine the fundamental parameters. NGC 1624 and NGC 1931 are, on average, reddened by <E(B-V)>=0.92+/-0.05 and 0.74+/-0.17mag, respectively. The properties of the reddening toward NGC 1931 indicate an abnormal reddening law (R_V,cl_=5.2+/-0.3). Using the zero-age main sequence fitting method we confirm that NGC 1624 is 6.0+/-0.6kpc away from the Sun, whereas NGC 1931 is at a distance of 2.3+/-0.2kpc. The results from isochrone fitting in the Hertzsprung-Russell diagram indicate the ages of NGC 1624 and NGC 1931 to be less than 4 and 1.5-2.0Myr, respectively. We derived the initial mass function (IMF) of the clusters. The slope of the IMF ({Gamma}_NGC1624_=-2.0+/-0.2 and {Gamma}_NGC1931_=-2.0+/-0.1) appears to be steeper than that of the Salpeter/Kroupa IMF. We discuss the implication of the derived IMF based on simple Monte-Carlo simulations and conclude that the property of star formation in the clusters does not seem to be significantly different from that in the solar neighborhood.
- ID:
- ivo://CDS.VizieR/J/AJ/162/140
- Title:
- The SOS. VII. UBVI photometry of open cluster IC 1590
- Short Name:
- J/AJ/162/140
- Date:
- 21 Mar 2022 00:39:36
- Publisher:
- CDS
- Description:
- Young open clusters are ideal laboratories to understand the star formation process. We present deep UBVI and H{alpha} photometry for the young open cluster IC1590 in the center of the HII region NGC281. Early-type members are selected from UBV photometric diagrams, and low-mass pre-main-sequence (PMS) members are identified by using H{alpha} photometry. In addition, the published X-ray source list and Gaia astrometric data are also used to isolate probable members. A total of 408 stars are selected as members. The mean reddening obtained from early-type members is <E(B-V)>=0.40{+/-}0.06(s.d.). We confirm the abnormal extinction law for the intracluster medium. The distance modulus to the cluster determined from the zero-age main-sequence fitting method is 12.3{+/-}0.2mag (d=2.88{+/-}0.28kpc), which is consistent with the distance d=2.70_-0.20_^+0.24^kpc from the recent Gaia parallaxes. We also estimate the ages and masses of individual members by means of stellar evolutionary models. The mode of the age of PMS stars is about 0.8Myr. The initial mass function of IC1590 is derived. It appears to be a steeper shape ({Gamma}=-1.49{+/-}0.14) than that of the Salpeter/Kroupa initial mass function for the high-mass regime (m>1M{sun}). The signature of mass segregation is detected from the difference in the slopes of the initial mass functions for the inner (r<2.5') and outer regions of this cluster. We finally discuss the star formation history in NGC281.
- ID:
- ivo://CDS.VizieR/J/ApJS/210/5
- Title:
- The twenty-five year Lick planet search
- Short Name:
- J/ApJS/210/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lick Planet Search program began in 1987 when the first spectrum of {tau} Ceti was taken with an iodine cell and the Hamilton Spectrograph. Upgrades to the instrument improved the Doppler precision from about 10m/s in 1992 to about 3m/s in 1995. The project detected dozens of exoplanets with orbital periods ranging from a few days to several years. The Lick survey identified the first planet in an eccentric orbit (70 Virginis) and the first multi-planet system around a normal main sequence star (Upsilon Andromedae). These discoveries advanced our understanding of planet formation and orbital migration. Data from this project helped to quantify a correlation between host star metallicity and the occurrence rate of gas giant planets. The program also served as a test bed for innovation with testing of a tip-tilt system at the Coud\'e focus and fiber scrambler designs to stabilize illumination of the spectrometer optics. The Lick Planet Search with the Hamilton Spectrograph effectively ended when a heater malfunction compromised the integrity of the iodine cell. Here, we present more than 14000 velocities for 386 stars that were surveyed between 1987 and 2011.
- ID:
- ivo://CDS.VizieR/III/250
- Title:
- The VIMOS VLT deep survey (VVDS-DEEP)
- Short Name:
- III/250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/733/123
- Title:
- The Wolf-Rayet content of M33 (NGC 598)
- Short Name:
- J/ApJ/733/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wolf-Rayet (WR) stars are evolved massive stars, and the relative number of WC-type and WN-type WRs should vary with metallicity, providing a sensitive test of stellar evolutionary theory. The observed WC/WN ratio is much higher than that predicted by theory in some galaxies but this could be due to observational incompleteness for WN types, which have weaker lines. Previous studies of M33's WR content show a galactocentric gradient in the relative numbers of WCs and WNs, but only small regions have been surveyed with sufficient sensitivity to detect all of the WNs. Here, we present a sensitive survey for WRs covering all of M33, finding 55 new WRs, mostly of WN type. Our spectroscopy also improves the spectral types of many previously known WRs, establishing in one case that the star is actually a background quasar. The total number of spectroscopically confirmed WRs in M33 is 206, a number we argue is complete to ~5%, with most WRs residing in OB associations, although ~2% are truly isolated.
- ID:
- ivo://CDS.VizieR/J/ApJ/497/736
- Title:
- The young cluster IC 348.
- Short Name:
- J/ApJ/497/736
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry in BVRI was obtained for about 260 stars in and around IC 348, and multiobject spectroscopy for 80 of these. A somewhat larger region was surveyed for stars having H{alpha} in emission; over 110 emission-line stars brighter than about R=19 were discovered. Because H{alpha}emission could be detected to a limit near W=3{AA}, division into weak-line (WTTSs) and classical T Tauri stars (CTTSs) was possible on purely spectroscopic grounds. There is a steep rise in the number of emission-line stars below W(H{alpha})=10{AA}; the proportion of WTTSs to CTTSs in the area surveyed is 58:51. ROSAT detected only about 58% of the spectroscopic WTTSs and about 65% of the CTTSs, although these numbers are sensitive to the survey thresholds. The bulk of the ages of about 100 stars, read off the theoretical tracks of D'Antona & Mazzitelli (1994ApJS...90..467D), range between about 0.7 and 12Myr, but the emission-line stars, which are most likely to be members of IC 348, have a mean age of 1.3Myr. Allowance for unresolved binaries would increase this somewhat, but there is a firm upper limit at 2.95Myr. There is no indication that the ages of the emission-line stars depend upon W(H{alpha}): the IC 348 WTTSs as a population are not systematically older than the CTTSs, but there is a tendency for the WTTSs to be concentrated toward the center of IC 348, while the CTTSs are more widely distributed. There is a scattering of emission-H{alpha} stars over the entire area surveyed. There are too many to be explained as low-mass members of an earlier generation of star formation in Per OB2 or as foreground dMe stars. The mass frequency function, based on some 125 stars fitted to theoretical tracks, rises from 1.5M_{sun}_; to about 0.2M_{sun}_;, with a slope very much like that of the Scalo initial mass function. The optical cluster IC 348 radius is about 4.0', or 0.37pc. The total mass of optically detectable stars in this volume is 57M_{sun}_;, while the mean space density is about 520 stars/pc^3^. The amount of interstellar material remaining within the cluster is small in comparison. Star formation in the Per OB2/IC 348 region cannot be characterized by one unique age; it appears that stars have been forming in the region now occupied by the association for 10-20Myr.
- ID:
- ivo://CDS.VizieR/III/189A
- Title:
- 12th General Catalogue of MK Classifications
- Short Name:
- III/189A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A file of MK spectral types and UBV photometry maintained at Dearborn Observatory is presented here. It is based on an extensive literature search and is up to date as of early 1995.
- ID:
- ivo://CDS.VizieR/III/223
- Title:
- 12th General Catalogue of MK Spectral Classification
- Short Name:
- III/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the twelfth in a series of catalogs of MK spectral types and UBV photometry issued from Dearborn Observatory. It is based on an extensive search of literature published up to early 1995. Each catalog is essentially self-contained, with its separate selection of stars listed in order of increasing right ascension. Some classifications (indicated between parentheses) are inferred from photometric or astrometric considerations. The preferred identification is from the Henry Draper Catalog or the General Catalog of Variable Stars, with a Durchmusterung or other alternative as space permits.
- ID:
- ivo://CDS.VizieR/III/222
- Title:
- 14th General Catalogue of MK Spectral Classification
- Short Name:
- III/222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourteenth in a series of catalogs of MK spectral types and UBV photometry issued from Dearborn Observatory. It is based on an extensive search of the literature published from ~1997 to 1999. Each catalog is essentially self-contained, with its separate selection of stars listed in order of increasing right ascension. Some classifications (indicated between parentheses) are inferred from photometric or astrometric considerations. The preferred identification is from the Henry Draper Catalog or the General Catalog of Variable Stars, with a Durchmusterung or other alternative as space permits.
