- ID:
- ivo://CDS.VizieR/J/other/RMxAA/38.141
- Title:
- Haffner 19 UBV(RI)_c_ photometry
- Short Name:
- J/other/RMxAA/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present broad-band UBV(RI)_c_ CCD imagery of 334 stars in the direction of the Galactic cluster Haffner 19. The sample is complete to m{lambda}=19 ({lambda} = U, B, V, R, I). We reliably establish the cluster membership for 102 stars based upon their locations in the (V, B-V), (V, V-I), (I, R-I), (U-B, B-V), and (V-R, V-I) diagrams, thus increasing three-fold the number of known cluster members. With the Q-method we determine the MK spectral types of the 33 brightest stars, confirming that 29 belong to the cluster's young population (15 B0-B1 and 14 B2- B9 main sequence stars). Complementary uvby{beta} photoelectric photometry of 6 bright stars independently confirms the distance and reddening to the cluster.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/509/A11
- Title:
- H{alpha} emission-line objects in SMC clusters
- Short Name:
- J/A+A/509/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Slitless CCD spectra were obtained covering the bulk (about 3 square degrees) of the Small Magellanic Cloud. For H{alpha} line-emission twice as strong as the ambient continuum, the survey is complete to spectral type B2/B3 on the main sequence. About 8120 spectra of 4437 stars were searched for emission lines in 84 open clusters, and 370 emission-line stars were found, among them at least 231 close to the main sequence. For 176 of them, photometry is available from the OGLE database. For comparison with a higher-metallicity environment, the Galactic sample of the photometric H{alpha} survey by McSwain & Gies (2005, Cat. <J/ApJS/161/118>) was used. Among early spectral sub-types, Be stars are more frequent by a factor ~3-5 in the SMC than in the Galaxy. The distribution with spectral type is similar in both galaxies, i.e., not strongly dependent on metallicity. The fraction of Be stars does not seem to vary with local star density. The Be phenomenon mainly sets in towards the end of the main-sequence evolution (this trend may be more pronounced in the SMC); but some Be stars already form with Be-star characteristics. In small subsamples (such as single clusters), even if they appear identical, the fraction of emission-line stars can deviate drastically from the mean. In all probability, the fractional critical angular rotation rate, OMC, is one of the main parameters governing the occurrence of the Be phenomenon. If the Be character is only acquired during the course of evolution, the key circumstance is the evolution of OMC, which is not only dependent on metallicity but differently so for different mass ranges. As a result, even if the Be phenomenon is driven basically by a single parameter (namely OMC), it can assume a complex multi-parametric appearance. The large cluster-to-cluster differences, which seem stronger than all other variations, serve as a caveat that this big picture may undergo significant second-order modulations (e.g., pulsations, initial angular momentum, etc).
- ID:
- ivo://CDS.VizieR/J/AJ/143/3
- Title:
- H{alpha} emission stars in IC 1274
- Short Name:
- J/AJ/143/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IC 1274 is a faintly luminous nebula lying on the near surface of the Lynds 227 (L227) molecular cloud. Its cavity-like morphology is reminiscent of a blistered star-forming region. Four luminous, early-type (B0-B5) stars are located within a spherical volume ~5' in diameter that appears to be clear of heavy obscuration. Approximately centered in the cleared region is the B0 V star HD 166033, which is thought to be largely responsible for the cavity's excavation. Over 80 H{alpha} emission sources brighter than V~21 have been identified in the region. More than half of these are concentrated in IC 1274 and are presumably members of a faint T Tauri star population. Chandra Advanced CCD Imaging Spectrometer imaging of a nearby suspected pulsar and time-variable {gamma}-ray source (GeV J1809-2327) detected 21 X-ray sources in the cluster vicinity, some of which are coincident with the early-type stars and H{alpha} emitters in IC 1274. Deep (V~22) optical BVRI photometry has been obtained for the cluster region. A distance of 1.82+/-0.3kpc and a mean extinction of AV~1.21+/-0.2mag follow from photometry of the early-type stars. Using pre-main-sequence evolutionary models, we derive a median age for the H{alpha} emitters and X-ray sources of ~1Myr; however, a significant dispersion is present. The displaced material was driven against what remains of the molecular cloud to the east, enabling the formation of the substantial number of T Tauri stars found there. A dispersed population of H{alpha} emitters is also found along the periphery of L227, IC 1275, and IC 4684.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/86
- Title:
- H{alpha} spectra & V-band photometry of {delta} Sco
- Short Name:
- J/ApJ/890/86
- Date:
- 04 Dec 2021
- Publisher:
- CDS
- Description:
- We model the circumstellar disk of {delta} Sco using the three-dimensional Monte Carlo radiative transfer code HDUST in order to quantify the large-scale changes in the disk through the years 2000-2018, and to see if these changes can be attributed to the secondary star affecting the disk throughout its orbit. We determine our best-fitting models through matching simulated observations to actual H{alpha} spectroscopy and V-band photometric observations. Our modeling results confirm previous findings that the disk of {delta}Sco was forming early in the century. We also find a period of disk dissipation when the companion is at apastron, as well as a significant growth of the disk between 2009 and 2011, prior to the periastron of 2011. Due to the steady-state nature of the disk after 2011, it is difficult to say whether the variations seen are due to the effect of the close passage of the binary companion.
- ID:
- ivo://CDS.VizieR/J/AJ/122/248
- Title:
- h and chi Per UBVI,H{alpha} photometry
- Short Name:
- J/AJ/122/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVI and H{alpha} photometry is presented for 17319 stars in vicinity of the young double cluster h and {chi} Persei. Our photometry extends over a 37'x1{deg} field centered on the association. We construct reddening contours within the imaged field. We find that the two clusters share a common distance modulus of 11.75+/-0.05 and ages of log[age(yr)]=7.1+/-0.1. From the V-H{alpha} color, a measure of the H{alpha} emission strength, we conduct a survey for emission line objects within the association. We detect a sample of 33 Be stars, eight of which are new detections. We present a scenario of evolutionary enhancement of the Be phenomenon to account for the peak in Be fraction toward the top of the main sequence in the population of h and {chi} Persei and similar young clusters. UBVI and H{alpha} photometry was performed on five nights between 1999 August 17 and 25 at the San Diego State University Mount Laguna Observatory with the 1m telescope and a Loral 2048x2048 CCD.
- ID:
- ivo://CDS.VizieR/J/MNRAS/408/475
- Title:
- HATNet Pleiades Rotation Period Catalogue
- Short Name:
- J/MNRAS/408/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the Hungarian-made Automated Telescope Network (HATNet) survey for transiting exoplanets, we measure photometric rotation periods for 368 Pleiades stars with 0.4~<M~<1.3M_{sun}_. We detect periodic variability for 74 per cent of the cluster members in this mass range that are within our field-of-view, and 93 per cent of the members with 0.7~<M~<1.0M_{sun}_. This increases, by a factor of 5, the number of Pleiades members with measured periods. We compare these data to the rich sample of spectroscopically determined projected equatorial rotation velocities (vsini) available in the literature for this cluster. Included in our sample are 14 newly identified probable cluster members which have proper motions, photometry and rotation periods consistent with membership.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/59
- Title:
- HAT-P-32 and HAT-P-33 follow-up
- Short Name:
- J/ApJ/742/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V=11.289 late-F-early-G dwarf star GSC 3281-00800, with a period P=2.150008+/-0.000001d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter (~80m/s). Assuming a circular orbit, the star has a mass of 1.16+/-0.04M_{sun}_ and radius of 1.22+/-0.02R_{sun}_, while the planet has a mass of 0.860+/-0.164M_J_ and a radius of 1.789+/-0.025R_J_. The second planet, HAT-P-33b, orbits the bright V=11.188 late-F dwarf star GSC 2461-00988, with a period P=3.474474+/-0.000001d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50m/s). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ~35m/s. We find that the star has a mass of 1.38+/-0.04M_{sun}_ and a radius of 1.64+/-0.03R_{sun}_ while the planet has a mass of 0.762+/-0.101M_J_ and a radius of 1.686+/-0.045R_J_ for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date.
688. HAT-P-12 light curve
- ID:
- ivo://CDS.VizieR/J/ApJ/706/785
- Title:
- HAT-P-12 light curve
- Short Name:
- J/ApJ/706/785
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the discovery of HAT-P-12b, a transiting extrasolar planet orbiting the moderately bright V~12.8 K4 dwarf GSC 03033-00706, with a period P=3.2130598+/-0.0000021d, transit epoch T_c_=2454419.19556+/-0.00020 (BJD), and transit duration 0.0974+/-0.0006d. The host star has a mass of 0.73+/-0.02M_{sun}_, radius of 0.70^+0.02^_-0.01_R_{sun}_, effective temperature 4650+/-60K, and metallicity [Fe/H]=-0.29+/-0.05. We find a slight correlation between the observed spectral line bisector spans and the radial velocity, so we consider, and rule out, various blend configurations including a blend with a background eclipsing binary, and hierarchical triple systems where the eclipsing body is a star or a planet. We conclude that a model consisting of a single star with a transiting planet best fits the observations, and show that a likely explanation for the apparent correlation is contamination from scattered moonlight. Based on this model, the planetary companion has a mass of 0.211+/-0.012M_J_ and radius of 0.959^+0.029^_-0.021_R_J_ yielding a mean density of 0.295+/-0.025g/cm^3^. Comparing these observations with recent theoretical models, we find that HAT-P-12b is consistent with a ~1-4.5Gyr, mildly irradiated, H/He-dominated planet with a core mass M_C_<~10M_{earth}_.
- ID:
- ivo://CDS.VizieR/J/AJ/155/119
- Title:
- HATSouth-K2 C7 transiting/eclipsing systems
- Short Name:
- J/AJ/155/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the result of a campaign to monitor 25 HATSouth candidates using the Kepler space telescope during Campaign 7 of the K2 mission. We discover HATS-36b (EPIC 215969174b, K2-145b), an eccentric (e=0.105+/-0.028) hot Jupiter with a mass of 3.216+/-0.062 M_J_ and a radius of 1.235+/-0.043 R_J_, which transits a solar-type G0V star (V=14.386) in a 4.1752-day period. We also refine the properties of three previously discovered HATSouth transiting planets (HATS-9b, HATS-11b, and HATS-12b) and search the K2 data for TTVs and additional transiting planets in these systems. In addition, we also report on a further three systems that remain as Jupiter-radius transiting exoplanet candidates. These candidates do not have determined masses, however pass all of our other vetting observations. Finally, we report on the 18 candidates that we are now able to classify as eclipsing binary or blended eclipsing binary systems based on a combination of the HATSouth data, the K2 data, and follow-up ground-based photometry and spectroscopy. These range in periods from 0.7 day to 16.7 days, and down to 1.5 mmag in eclipse depths. Our results show the power of combining ground-based imaging and spectroscopy with higher precision space-based photometry, and serve as an illustration as to what will be possible when combining ground-based observations with TESS data.
- ID:
- ivo://CDS.VizieR/J/A+A/371/908
- Title:
- Havlen-Moffat No. 1 UBVRI photometry
- Short Name:
- J/A+A/371/908
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deep CCD UBVRI photometric survey combined with UBVRI polarimetric observations of 21 bright stars was carried out in the region of the open cluster Havlen-Moffat No. 1. Our data reveal that the extinction law in this cluster es variable and that six cluster stars show very high polarisation values (>4%), probably because of the presence of a nearby small dust cloud. The cluster is at a distance of d=3300pc, it is 2-4Myr old and the initial mass function of its most massive stars (M>3M_{sun}_) has a flat slope of x about of 0.7. As an additional result, it was possible to reconcile the absolute magnitudes of the two WN7-type members using the R-values valid in the regions where they are located.
