- ID:
- ivo://CDS.VizieR/J/ApJ/796/48
- Title:
- Potential exoplanet targets with Palomar/TripleSpec
- Short Name:
- J/ApJ/796/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we explore the capabilities of NASA's 3.0 m Infrared Telescope Facility (IRTF) and SpeX spectrometer and the 5.08 m Hale telescope with the TripleSpec spectrometer with near-infrared H-, K-, and L-band measurements of HD 209458b's secondary eclipse. Our IRTF/SpeX data are the first absolute L-band spectroscopic emission measurements of any exoplanet other than the hot Jupiter HD 189733b. Previous measurements of HD 189733b's L band indicate bright emission hypothesized to result from non-LTE CH_4_{nu}_3_ fluorescence. We do not detect a similar bright 3.3 {mu}m feature to ~3{sigma}, suggesting that fluorescence does not need to be invoked to explain HD 209458b's L-band measurements. The validity of our observation and reduction techniques, which decrease the flux variance by up to 2.8 orders of magnitude, is reinforced by 1{sigma} agreement with existent Hubble/NICMOS and Spitzer/IRAC1 observations that overlap the H, K, and L bands, suggesting that both IRTF/SpeX and Palomar/TripleSpec can measure an exoplanet's emission with high precision.
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- ID:
- ivo://CDS.VizieR/J/ApJ/842/83
- Title:
- Praesepe members rotational periods from K2 LCs
- Short Name:
- J/ApJ/842/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze K2 light curves for 794 low-mass (1>~M_*_>~0.1M_{sun}_) members of the ~650Myr old open cluster Praesepe and measure rotation periods (P_rot_) for 677 of these stars. We find that half of the rapidly rotating >~0.3M_{sun}_ stars are confirmed or candidate binary systems. The remaining >~0.3M_{sun}_ fast rotators have not been searched for companions, and are therefore not confirmed single stars. We previously found that nearly all rapidly rotating 0.3M_{sun}_ stars in the Hyades are binaries, but we require deeper binary searches in Praesepe to confirm whether binaries in these two co-eval clusters have different P_rot_ distributions. We also compare the observed P_rot_ distribution in Praesepe to that predicted by models of angular-momentum evolution. We do not observe the clear bimodal P_rot_ distribution predicted by Brown (2014ApJ...789..101B) for >0.5M_{sun}_ stars at the age of Praesepe, but 0.25-0.5M_{sun}_ stars do show stronger bimodality. In addition, we find that >60% of early M dwarfs in Praesepe rotate more slowly than predicted at 650Myr by Matt+ (2015ApJ...799L..23M), which suggests an increase in braking efficiency for these stars relative to solar-type stars and fully convective stars. The incompleteness of surveys for binaries in open clusters likely impacts our comparison with these models since the models only attempt to describe the evolution of isolated single stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/347/101
- Title:
- Precision colour-magnitude diagram of M67
- Short Name:
- J/MNRAS/347/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have calibrated and combined an extensive set of BVI observations of M67 to produce a colour-magnitude diagram of stars measured with high relative precision. We have selected stars that are most likely to be single-star members of the cluster using proper motion, radial velocity, and variability information from the literature, and an examination of the most probable colour-magnitude diagram locations of unresolved stellar blends. We have made detailed comparisons of our photometry of the selected stars with theoretical models, and discuss the most notable discrepancies. Observations of M67 turn-off stars are a severe test of algorithms attempting to describe convective cores in the limit of small extent, and we find strong evidence of a 'hook' just fainter than the turn-off gap. The stars in M67 support assertions that the degree of convective core overshooting decreases to zero for stars with masses in the range 1.0<(M/M_{sun}_)<=1.5, but that the degree of overshoot is smaller than currently used in published isochrones. We also verify that all current theoretical models for the lower main sequence (with the exception of Baraffe et al., 1998, Cat. J/A+A/337/403) are too blue for MV>~6, even when the sequences are shifted to match M67 near the MV of the Sun, probably due to a combination of problems with colour-Teff transformations and realistic surface boundary conditions for models. Finally, we identify a subset of cluster members with unusual photometry (candidate red giant binaries, blue straggler stars, and triple systems) deserving of further study.
- ID:
- ivo://CDS.VizieR/J/AJ/140/925
- Title:
- Pre-eruption light curves for Nova U Sco
- Short Name:
- J/AJ/140/925
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by B.G. Harris and S. Dvorak on JD 2455224.9385 (2010 January 28.4385 UT) of the predicted eruption of the recurrent nova U Scorpii (U Sco). We also report 815 magnitudes (and 16 useful limits) on the pre-eruption light curve in the UBVRI and Sloan r' and i' bands from 2000.4 up to 9hr before the peak of the 2010 January eruption.
- ID:
- ivo://CDS.VizieR/J/ApJ/658/480
- Title:
- Pre-main-sequence stars in Lupus association
- Short Name:
- J/ApJ/658/480
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kinematical analysis of spectroscopically identified pre-main-sequence stars associated with the Lupus dark cloud reveals a streamlike motion of low internal velocity dispersion (<=1.3km/s). A statistically significant mismatch between the convergent point radial velocity and the spectroscopic radial velocity from the literature indicates a moderate degree of expansion. The rate of expansion is too low to account for the present extent of the association if one assumes that the spatially dispersed population was formed in the dense molecular cores observed today. Therefore, it is unlikely that the outlying weak-lined T Tauri members were born in the same star-forming cores as the more compactly located classical T Tauri stars, despite the kinematic integrity of the association. Distances inferred from the classical moving-cluster method show a large depth of the association (~80pc) along the line of sight. A color-magnitude diagram of the association in the near-IR colors corrected for the distribution of distances shows a clear gap separating the older (5-27Myr) and the younger (~1Myr) generations of stars. Half of the identified 1Myr old stars lie in the tight group of mostly classical T Tauri stars associated with the Lupus 3 dark filament. This nest of very young stars appears to be 25pc farther from the Sun than the center of the greater Lupus association.
- ID:
- ivo://CDS.VizieR/J/A+A/438/769
- Title:
- Pre-main sequence stars Proper Motion Catalog
- Short Name:
- J/A+A/438/769
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue presents astrometric (position and proper motion) and photometric parameters for 1250 PMS stars and 104 PMS star candidates spread over all-sky major star-forming regions. We provide for each star the mean (J2000.0) position and proper motion derived from CCD meridian observations(Bordeaux and Valinhos CCD meridian circle), ESOD1.5m and OHP120cm telescopes, Schmidt SERC-J, POSS I and POSS II plates digitized with the MAMA measuring machine (Paris) and published catalogues as AC2000.2 (<I/275>), USNO-A2.0 (<I/252>), HIPPARCOS (<I/239>), Tycho-2 (<I/259>), UCAC2 (<I/289>), 2MASS (<II/246>) and other astrometric sources. We also provide, when available, CCD meridian V magnitude and the J, H, K magnitudes from 2MASS catalogue. Precision on proper motions vary from 2 to 5mas/yr depending on the used sources of ancient positions and depending also on the embedding and binarity of the source. The V limiting magnitude of our catalogue is about 16.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/696/L84
- Title:
- Primordial circumstellar disks in binary systems
- Short Name:
- J/ApJ/696/L84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine the results from several multiplicity surveys of pre-main-sequence stars located in four nearby star-forming regions with Spitzer data from three different Legacy Projects. This allows us to construct a sample of 349 targets, including 125 binaries, which we use to to investigate the effect of companions on the evolution of circumstellar disks. We find that the distribution of projected separations of systems with Spitzer excesses is significantly different (P~2.4e-5, according to the K-S test for binaries with separations less than 400AU) from that of systems lacking evidence for a disk. As expected, systems with projected separations less than 40AU are half as likely to retain at least one disk than are systems with projected separations in the 40-400AU range. These results represent the first statistically significant evidence for a correlation between binary separation and the presence of an inner disk (r~1AU). Several factors (e.g., the incompleteness of the census of close binaries, the use of unresolved disk indicators, and projection effects) have previously masked this correlation in smaller samples. We discuss the implications of our findings for circumstellar disk lifetimes and the formation of planets in multiple systems.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/32
- Title:
- Probable young stars in the MYStIX project
- Short Name:
- J/ApJS/209/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Massive Young star-forming complex Study in Infrared and X-rays (MYStIX) project requires samples of young stars that are likely members of 20 nearby Galactic massive star-forming regions. Membership is inferred from statistical classification of X-ray sources, from detection of a robust infrared excess that is best explained by circumstellar dust in a disk or infalling envelope and from published spectral types that are unlikely to be found among field stars. We present the MYStIX membership lists here, and describe in detail the statistical classification of X-ray sources via a "Naive Bayes Classifier."
- ID:
- ivo://CDS.VizieR/J/ApJ/800/120
- Title:
- Profiles of z<0.5 galaxies with Pan-STARRS1
- Short Name:
- J/ApJ/800/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an analysis of Pan-STARRS1 Medium Deep Survey multi-band (grizy) images of a sample of 698 low-redshift disk galaxies that span broad ranges in stellar mass, star-formation rate, and bulge/disk ratio. We use population synthesis spectral energy distribution fitting techniques to explore the radial distribution of the light, color, surface mass density, mass/light ratio, and age of the stellar populations. We characterize the structure and stellar content of the galaxy disks out to radii of about twice Petrosian r_90_, beyond which the halo light becomes significant. We measure normalized radial profiles for sub-samples of galaxies in three bins each of stellar mass and concentration. We also fit radial profiles to each galaxy. The majority of galaxies have down-bending radial surface brightness profiles in the bluer bands with a break radius at roughly r_90_. However, they typically show single unbroken exponentials in the reddest bands and in the stellar surface mass density. We find that the mass/light ratio and stellar age radial profiles have a characteristic "U" shape. There is a good correlation between the amplitude of the down-bend in the surface brightness profile and the rate of the increase in the M/L ratio in the outer disk. As we move from late- to early-type galaxies, the amplitude of the down-bend and the radial gradient in M/L both decrease. Our results imply a combination of stellar radial migration and suppression of recent star formation can account for the stellar populations of the outer disk.
- ID:
- ivo://CDS.VizieR/J/A+AS/142/373
- Title:
- Proper motions and BVRI photometry in NGC 4147
- Short Name:
- J/A+AS/142/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Astrometry and B VRI CCD photometry of 115 stars down to B=17.6 in the region of about 11'x11' around the globular cluster NGC 4147 was performed. In the astrometric reduction, three earlier epoch plates taken at Sheshan, Shanghai, China, in 1958 and four recent epoch B-passband CCD frames taken at Kavalur, India, were used. The data were reduced to a catalogue based on measurements of stars on seven plates with an epoch period from 1917 to 1979 taken in Bonn, Germany, and ultimately to the Hipparcos catalogue. The reduction was done with the central overlapping method. Based on the new proper motion data, the membership probabilities of 115 stars were determined. Furthermore, three colour-magnitude diagrams (CMD) of V versus B-V, V-R and V-I, respectively, for HB and GB stars were constructed from CCD photometry obtained with the Vainu Bappu Telescope. An absolute proper motion of the cluster of -2.08+/-0.48mas/yr in right ascension and -3.07+/-0.46mas/yr in declination has been obtained. The space velocity and apogalactic distance of the cluster with respect to the Galactic standard of rest were calculated. In contrast to the first results given in the literature we obtain a significantly lower velocity and a smaller apogalactic distance for NGC 4147.
