- ID:
- ivo://CDS.VizieR/J/MNRAS/411/263
- Title:
- JHK variable stars in M33
- Short Name:
- J/MNRAS/411/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M 33 (Triangulum). The main aim was to identify stars in the very final stage of their evolution, and for which the luminosity is more directly related to the birth mass than the more numerous less-evolved giant stars that continue to increase in luminosity. The most extensive dataset was obtained in the K-band with the UIST instrument for the central 4'x4' (1kpc^2^) --- this contains the nuclear star cluster and inner disc. These data, taken during the period 2003-2007, were complemented by J- and H-band images. Photometry was obtained for 18,398 stars in this region; of these, 812 stars were found to be variable, most of which are Asymptotic Giant Branch (AGB) stars. Our data were matched to optical catalogues of variable stars and carbon stars, and to mid-infrared photometry from the Spitzer Space Telescope. In this first of a series of papers, we present the methodology of the variability survey and the photometric catalogue, which is made publicly available at the Centre de Donnees astronomiques de Strasbourg (CDS), and discuss the properties of the variable stars. Most dusty AGB stars had not been previously identified in optical variability surveys, and our survey is also more complete for these types of stars than the Spitzer survey.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/BASI/35.53
- Title:
- JH photometry of Berkeley 59
- Short Name:
- J/other/BASI/35.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared JH photometry and optical slitless spectroscopy of stars in the field of the young cluster Be 59. The J/(J-H) colour-magnitude diagram of the cluster yields a distance modulus of (m-M)_0_=10.0+/-0.2mag, which corresponds to a distance of 1.0+/-0.1kpc. Using the slitless spectroscopy we identified 9 H{alpha} emission line stars in the observed region. The location of H{alpha} stars in the CMD indicates that they may be pre-main sequence stars. We have estimated the age of the cluster using the turn-off and turn-on points and is found to lie between ~1Myr to 4Myr. Two massive stars (~25M_{sun}_) in the cluster region have high membership probability which indicates that the low mass stars (~0.8M_{sun}_) may co-exist with massive stars.
1413. Ji light curves of WTS-2
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/1470
- Title:
- Ji light curves of WTS-2
- Short Name:
- J/MNRAS/440/1470
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of WTS-2 b, an unusually close-in 1.02-d hot Jupiter (M_P_=1.12M_J_, R_P_=1.30R_J_) orbiting a K2V star, which has a possible gravitationally bound M-dwarf companion at 0.6-arcsec separation contributing ~20% of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe overflow, and has a predicted remaining lifetime of just ~40Myr, assuming a tidal dissipation quality factor of Q'_*_=10^6^. Q'_*_ is a key factor in determining how frictional processes within a host star affect the orbital evolution of its companion giant planets, but it is currently poorly constrained by observations. We calculate that the orbital decay of WTS-2 b would correspond to a shift in its transit arrival time of T_shift_~17s after 15yr assuming Q'_*_=10^6^. A shift less than this would place a direct observational constraint on the lower limit of Q'_*_ in this system. We also report a correction to the previously published expected T_shift_ for WASP-18 b, finding that T_shift_=356s after 10yr for Q'_*_10^6^, which is much larger than the estimated 28s quoted in WASP-18 b discovery paper. We attempted to constrain Q'_*_ via a study of the entire population of known transiting hot Jupiters, but our results were inconclusive, requiring a more detailed treatment of transit survey sensitivities at long periods. We conclude that the most informative and straightforward constraints on Q'_*_ will be obtained by direct observational measurements of the shift in transit arrival times in individual hot Jupiter systems. We show that this is achievable across the mass spectrum of exoplanet host stars within a decade, and will directly probe the effects of stellar interior structure on tidal dissipation.
- ID:
- ivo://CDS.VizieR/J/A+A/372/879
- Title:
- JKBV photometry of NGC 2141
- Short Name:
- J/A+A/372/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report CCD optical (B and V passbands) and near IR (J and K bands) observations in the region of the old open cluster NGC 2141. By combining the two sets of photometry (500 stars in common) we derive new estimates of the cluster's fundamental parameters. We confirm that the cluster is 2.5Gyrs old, but, with respect to previous investigations, we obtain a slightly larger reddening (E(B-V)=0.40), and a slightly shorter distance (3.8kpc) from the Sun. Finally, we present the Luminosity Function (LF) in the V band, which is another age indicator. We provide a good fit for the age range inferred from isochrones by assuming the Kroupa et al. (1993MNRAS.262..545K) IMF up to M_V_=5.0. We interpret the disagreement at fainter magnitudes as evidence of mass segregation.
- ID:
- ivo://CDS.VizieR/J/A+A/413/1037
- Title:
- J-K DENIS photometry of bright southern stars
- Short Name:
- J/A+A/413/1037
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric survey of bright southern stars carried out using the DENIS instrument equipped with attenuating filters. The observations were carried out not using the survey mode of DENIS, but with individual target pointings. This project was stimulated by the need to obtain near-infrared photometry of stars to be used in early commissioning observations of the ESO Very Large Telescope Interferometer, and in particular to establish a network of bright calibrator sources. We stress that near-infrared photometry is peculiarly lacking for many bright stars. These stars are saturated in 2MASS as well as in regular DENIS observations. The only other observations available for bright infrared stars are those of the Two Micron Sky Survey (<II/2>) dating from over thirty years ago. These were restricted to declinations above -30{deg} and thus cover only about half of the sky accessible from the VLTI site. We note that the final 2MASS data release includes photometry of bright stars, obtained by means of point-spread function fitting. However, this method only achieves about 30 percent accuracy, which is not sufficient for most applications. In this work, we present photometry for over 600 stars, each with at least one and up to eight measurements, in the J and K filters. Typical accuracy is at the level of 0.05mag and 0.04mag in the J and Ks bands, respectively.
- ID:
- ivo://CDS.VizieR/II/289
- Title:
- JKH photometry in LDN 1688
- Short Name:
- II/289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A review of star formation in the Rho Ophiuchi molecular complex is presented, with particular emphasis on studies of the main cloud, L1688, since 1991. Recent photometric and parallax measurements of stars in the Upper Scorpius subgroup of the Sco-Cen OB association suggest a distance for the cloud between 120 and 140 parsecs. Star formation is ongoing in the dense cores of L1688 with a median age for young stellar objects of 0.3Myr. The surface population appears to have a median age of 2-5Myr and merges with low mass stars in the Upper Scorpius subgroup. Making use of the most recent X-ray and infrared photometric surveys and spectroscopic surveys of L1688, we compile a list of over 300 association members with counterparts in the 2MASS catalog. Membership criteria, such as lithium absorption, X-ray emission, and infrared excess, cover the full range of evolutionary states for young stellar objects. Spectral energy distributions are classified for many association members using infrared photometry obtained from the Spitzer Space Telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A98
- Title:
- JK photometry in BUL_SC9 and BUL_SC29
- Short Name:
- J/A+A/559/A98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In some scenarios for the formation of the Milky Way bulge, the stellar population at the edges of the boxy bulge may be younger than those on the minor axis or close to the Galactic center. So far the only bulge region where deep color-magnitude diagrams have been obtained is indeed along the minor axis. To overcome this limitation, we aim to age-date the bulge stellar populations far away from the bulge minor axis. Color-magnitude diagrams and luminosity functions have been obtained from deep near-IR VLT/HAWK-I images taken at the two Southern corners of the boxy bulge, i.e., near the opposite edges of the Galactic bar. The foreground disk contamination has been statistically removed using a pure disk field observed with the same instrument and located approximately at similar Galactic latitudes of the two bulge fields and ~30{deg} in longitude away from the Galactic center. For each bulge field, mean reddening and distance are determined using the position of red clump stars, and the metallicity distribution is derived photometrically using the color distribution of stars in the upper red giant branch.
- ID:
- ivo://CDS.VizieR/J/ApJ/505/50
- Title:
- JK photometry in SA 57-6575, Her 1-5677 fields
- Short Name:
- J/ApJ/505/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Keck 10m telescope to count objects as a function of image size in two high Galactic latitude fields covering 1.5arcmin^2^ and reaching 50% completeness depths of K=24 and J=24.5 for stellar sources. Our counts extend ~1mag deeper in K than those of surveys with other telescopes; complement other Keck surveys in the K-band that provide counts at comparable or shallower depths but that have not utilized image structure; and extend by several magnitudes the J-band counts from brighter surveys using smaller telescopes that cover larger areas.
- ID:
- ivo://CDS.VizieR/J/AJ/150/176
- Title:
- JK photometry of 12 galactic globular clusters
- Short Name:
- J/AJ/150/176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide field near-infrared (near-IR) photometry of 12 Galactic globular clusters, typically extending from the tip of the cluster red giant branch (RGB) to the main sequence turnoff. Using recent homogenous values of cluster distance, reddening and metallicity, the resulting photometry is directly compared to the predictions of several recent libraries of stellar evolutionary models. Of the sets of models investigated, Dartmouth and Victoria-Regina models best reproduce the observed RGB morphology, albeit with offsets in J-K_S_ color which vary in their significance in light of all sources of observational uncertainty. Therefore, we also present newly recalibrated relations between near-IR photometric indices describing the upper RGB versus cluster iron abundance as well as global metallicity. The influence of enhancements in alpha elements and helium are analyzed, and we find that the former affect the morphology of the upper RGB in accord with model predictions. Meanwhile, the empirical relations we derive are in good agreement with previous results, and minor discrepancies can likely be attributed to differences in the assumed cluster distances and reddenings. In addition, we present measurements of the horizontal branch (HB) and RGB bump magnitudes, finding a non-negligible dependence of the near-IR HB magnitude on cluster metallicity. Lastly, we discuss the influence of assumed cluster distances, reddenings and metallicities on our results, finding that our empirical relations are generally insensitive to these factors to within their uncertainties.
- ID:
- ivo://CDS.VizieR/J/AJ/119/2274
- Title:
- JK Photometry of globular clusters M15 & M56
- Short Name:
- J/AJ/119/2274
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared JKs-band photometry of the Galactic globular clusters M15 and, for the first time, M56 is presented. We estimate the reddening [E(B-V) = 0.18 {=/-} 0.08 mag] and distance modulus [(m - M)V = 15.43 {+/-} 0.30 mag] toward the poorly studied globular cluster M56. We combine our data with observations of other clusters from the literature (12 in total) to extend the [Fe/H] versus red giant branch (RGB) slope relation toward metal-poor clusters.
