- ID:
- ivo://CDS.VizieR/J/other/JAVSO/34.222
- Title:
- New Northern Hemisphere Variables
- Short Name:
- J/other/JAVSO/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey looking for previously unknown variable stars has been carried out in the declination range 30-39 degrees and in the R.A. range 0-24 hours. The survey was done in I-band, and was carried out from October 2003 to December of 2004. Seventy-five new and previously suspected variable stars were detected. This paper presents a brief description of the survey and identifies the new variables.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/3855
- Title:
- New OB star candidates in Carina Arm
- Short Name:
- J/MNRAS/450/3855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- O and early B stars are at the apex of galactic ecology, but in the Milky Way, only a minority of them may yet have been identified. We present the results of a pilot study to select and parametrize OB star candidates in the Southern Galactic plane, down to a limiting magnitude of g=20. A 2 deg^2^ field capturing the Carina Arm around the young massive star cluster, Westerlund 2, is examined. The confirmed OB stars in this cluster are used to validate our identification method, based on selection from the (u-g, g-r) diagram for the region. Our Markov Chain Monte Carlo fitting method combines VPHAS+ u, g, r, i with published J, H, K photometry in order to derive posterior probability distributions of the stellar parameters log(Teff) and distance modulus, together with the reddening parameters A_0_ and R_V_. The stellar parameters are sufficient to confirm OB status while the reddening parameters are determined to a precision of {sigma}(A_0_)~0.09 and {sigma}(R_V_)~0.08. There are 489 objects that fit well as new OB candidates, earlier than ~ B2. This total includes 74 probable massive O stars, 5 likely blue supergiants and 32 reddened subdwarfs. This increases the number of previously known and candidate OB stars in the region by nearly a factor of 10. Most of the new objects are likely to be at distances between 3 and 6 kpc. We have confirmed the results of previous studies that, at these longer distances, these sight lines require non-standard reddening laws with 3.5<R_V_<4.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2327
- Title:
- New proper motion objects from UKIDSS GPS
- Short Name:
- J/MNRAS/443/2327
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The UKIDSS Galactic Plane Survey (GPS) began in 2005 as a seven year effort to survey ~1800deg^2^ of the northern Galactic plane in the J, H, and K passbands. The survey included a second epoch of K-band data, with a baseline of two to eight years, for the purpose of investigating variability and measuring proper motions. We have calculated proper motions for 167 million sources in a 900deg^2^ area located at l>60{deg} in order to search for new high proper motion objects. Visual inspection has verified 617 high proper motion sources (>200mas/yr) down to K=17, of which 153 are new discoveries. Among these, we have a new spectroscopically confirmed T5 dwarf, an additional T dwarf with estimated type T6, 13 new L dwarf candidates, and two new common proper motion systems containing ultracool dwarf candidates. We provide improved proper motions for an additional 12 high proper motion stars that were independently discovered in the WISE data set during the course of this investigation.
- ID:
- ivo://CDS.VizieR/J/AJ/133/2898
- Title:
- New proper-motion stars (-90<DE< -47)
- Short Name:
- J/AJ/133/2898
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 1606 new proper-motion systems in the southern sky (declinations -90{deg} to -47{deg}) with 0.40"/yr>{mu}>=0.18"/yr. This effort is a continuation of the SuperCOSMOS-RECONS (SCR) proper-motion search to lower proper motions than reported in Papers VIII, X, XII, and XV in this series. Distance estimates are presented for the new systems, assuming that all stars are on the main sequence. We find that 31 systems are within 25pc, including two systems (SCR 0838-5855 and SCR 1826-6542) that we anticipate to be within 10pc. These new discoveries constitute a more than 10-fold increase in new systems found in the same region of sky searched for systems with mu>=0.40"/yr, suggesting a happy hunting ground for new nearby slower proper-motion systems in the region just north (declinations -47{deg} to 0{deg}), much of which has not been rigorously searched during previous efforts.
- ID:
- ivo://CDS.VizieR/J/AJ/142/92
- Title:
- New proper motion stars with pm>=0.18"/yr
- Short Name:
- J/AJ/142/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we present 1584 new southern proper motion systems with {mu}>=0.18"/yr and 16.5>R_59F_>=18.0. This search complements the six previous SuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky for stars within the same proper motion range, but with R_59F_<=16.5. As in previous papers, we present distance estimates for these systems and find that three systems are estimated to be within 25pc, including one, SCR 1546-5534, possibly within the RECONS 10pc horizon at 6.7pc, making it the second nearest discovery of the searches. We find 97 white dwarf candidates with distance estimates between 10 and 120pc, as well as 557 cool subdwarf candidates.
- ID:
- ivo://CDS.VizieR/J/AJ/142/10
- Title:
- New proper motion stars 0.40"/yr>pm>=0.18"/yr
- Short Name:
- J/AJ/142/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 2817 new southern proper motion systems with 0.40"/yr>{mu}>=0.18"/yr and declination between -47{deg} and 00{deg}. This is a continuation of the SuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky. We use the same photometric relations as previous searches to provide distance estimates based on the assumption that the objects are single main-sequence stars. We find 79 new red dwarf systems predicted to be within 25pc, including a few new components of previously known systems.
- ID:
- ivo://CDS.VizieR/J/AJ/154/57
- Title:
- New SDSS and Washington photometry in Segue 3
- Short Name:
- J/AJ/154/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new SDSS and Washington photometry of the young outer-halo stellar system Segue 3. Combined with archival VI-observations, our most consistent results yield Z=0.006+/-0.001, log(Age)=9.42+/-0.08, (m-M)_0_=17.35+/-0.08, and E(B-V)=0.09+/-0.01, with a high binary fraction of 0.39+/-0.05 derived using the Padova models. We confirm that mass-segregation has occurred, supporting the hypothesis that this cluster is being tidally disrupted. A three-parameter King model yields a cluster radius of r_cl_=0.017{deg}+/-0.007{deg}, a core radius of r_c_=0.003{deg}+/-0.001{deg}, and a tidal radius of r_t_=0.04{deg}+/-0.02{deg}. A comparison of Padova and Dartmouth model-grids indicates that the cluster is not significantly {alpha}-enhanced, with a mean [Fe/H]=-0.55_-0.12_^+0.15^dex, and a population age of only 2.6+/-0.4Gyr. We rule out a statistically significant age spread at the main-sequence turnoff because of a narrow subgiant branch, and discuss the role of stellar rotation and cluster age, using Dartmouth and Geneva models: approximately 70% of the Seg 3 stars at or below the main-sequence turnoff have enhanced rotation. Our results for Segue 3 indicate that it is younger and more metal-rich than all previous studies have reported to date. From colors involving Washington C and SDSS-u filters, we identify several giants and a possible blue straggler for future follow-up spectroscopic studies, and we produce spectral energy distributions of previously known members and potential Segue 3 sources with Washington (CT_1_), Sloan (ugri), and VI-filters. Segue 3 shares the characteristics of unusual stellar systems that have likely been stripped from external dwarf galaxies as they are being accreted by the Milky Way, or that have been formed during such an event. Its youth, metallicity, and location are all inconsistent with Segue 3 being a cluster native to the Milky Way.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/143
- Title:
- New SpeX Observations of M7-L6 Dwarfs
- Short Name:
- J/ApJ/794/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations (<=1 AU), leading to uncertainty in the overall binary fraction. We approach this problem by searching for late-M/early-L plus T dwarf spectral binaries whose combined light spectra exhibit distinct peculiarities, allowing for separation-independent identification. We define a set of spectral indices designed to identify these systems, and we use a spectral template fitting method to confirm and characterize spectral binary candidates from a library of 815 spectra from the SpeX Prism Spectral Libraries. We present 11 new binary candidates, confirm 3 previously reported candidates, and rule out 2 previously identified candidates, all with primary and secondary spectral types in the range M7-L7 and T1-T8, respectively. We find that subdwarfs and blue L dwarfs are the primary contaminants in our sample and propose a method for segregating these sources. If confirmed by follow-up observations, these systems may add to the growing list of tight separation binaries, whose orbital properties may yield further insight into brown dwarf formation scenarios.
- ID:
- ivo://CDS.VizieR/J/MNRAS/365/447
- Title:
- New stellar members of Coma Berenices cluster
- Short Name:
- J/MNRAS/365/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey of the Coma Berenices open star cluster (Melotte 111), undertaken using proper motions from the USNO-B1.0 (United States Naval Observatory, <I/284>) and photometry from the Two-Micron All-Sky Survey (2MASS, <II/246>) Point Source catalogues. We have identified 60 new candidate members with masses in the range 1.007<M<0.269M_{sun}_. For each we have estimated a membership probability by extracting control clusters from the proper motion vector diagram. All 60 are found to have greater than 60 per cent probability of being members, more than doubling the number of known cluster members. The new luminosity function for the cluster peaks at bright magnitudes, but is rising at K>>12, indicating that it is likely that lower mass members may exist. The mass function also supports this hypothesis.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A3
- Title:
- New survey of supergiants in the MCs
- Short Name:
- J/A+A/578/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership to the clouds. Around two hundred new RSGs have been detected, hinting at a yet to be observed large population. Using near and mid infrared photometry we study the brightness distribution of these stars, the onset of mass-loss and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid and near infrared photometry to improve the observational efficiency of similar programs as this.
