- ID:
- ivo://CDS.VizieR/J/A+A/476/1019
- Title:
- RMS survey of southern candidate massive YSOs
- Short Name:
- J/A+A/476/1019
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Red MSX Source (RMS) survey is an ongoing effort to return a large, well-selected sample of massive young stellar objects (MYSOs) within our Galaxy. 2000 candidates have been colour-selected from the Mid-course Space Experiment (MSX) point source catalogue (PSC). A series of ground-based follow-up observations are being undertaken in order to remove contaminant objects (ultra-compact HII (UCHII) regions, planetary nebulae (PN), evolved stars), and to begin characterising these MYSOs. As a part of these follow-up observations, high resolution (~1") mid-IR imaging aids the identification of contaminant objects which are resolved (UCHII regions, PN) as opposed to those which are unresolved (YSOs, evolved stars) as well as identifying YSOs near UCHII regions and other multiple sources. We present 10.4{mu}m imaging observations for 346 candidate MYSOs in the RMS survey in the Southern Hemisphere, primarily outside the region covered by the GLIMPSE Spitzer Legacy Survey. These were obtained using TIMMI2 on the ESO 3.6m telescope in La Silla, Chile. Our photometric accuracy is of order 0.05Jy, and our astrometric accuracy is 0.8", which is an improvement over the nominal 2" accuracy of the MSX PSC.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/588/A54
- Title:
- roAp star alpha Cir blue and red light curves
- Short Name:
- J/A+A/588/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on an analysis of high-precision, multi-colour photometric observations of the rapidly-oscillating Ap (roAp) star alpha Cir. These observations were obtained with the BRITE-Constellation, which is a coordinated mission of five nanosatellites that collects continuous millimagnitude-precision photometry of dozens of bright stars for up to 180-days at a time in two colours (~Johnson B and R). BRITE stands for BRight Target Explorer. The object Cir is the brightest roAp star and an ideal target for such investigations, facilitating the determination of oscillation frequencies with high resolution. This star is bright enough for complementary interferometry and time-resolved spectroscopy. Four BRITE satellites observed alpha Cir for 146d or 33 rotational cycles. Phasing the photometry according to the 4.4790d rotational period reveals qualitatively different light variations in the two photometric bands. The phased red-band photometry is in good agreement with previously-published WIRE data, showing a light curve symmetric about phase 0.5 with a strong contribution from the first harmonic. The phased blue-band data, in contrast, show an essentially sinusoidal variation. We model both light curves with Bayesian Photometric Imaging, which suggests the presence of two large-scale, photo- metrically bright (relative to the surrounding photosphere) spots. We also examine the high-frequency pulsation spectrum as encoded in the BRITE photometry. Our analysis establishes the stability of the main pulsation frequency over the last ~20-years, confirms the presence of frequency f_7_, which was not detected (or the mode not excited) prior to 2006, and excludes quadrupolar modes for the main pulsation frequency.
- ID:
- ivo://CDS.VizieR/J/AJ/155/51
- Title:
- Robo-AO binary star systems in 3 open clusters
- Short Name:
- J/AJ/155/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify and roughly characterize 66 candidate binary star systems in the Pleiades, Praesepe, and NGC 2264 star clusters, based on robotic adaptive optics imaging data obtained using Robo-AO at the Palomar 60" telescope. Only ~10% of our imaged pairs were previously known. We detect companions at red optical wavelengths, with physical separations ranging from a few tens to a few thousands of au. A three-sigma contrast curve generated for each final image provides upper limits to the brightness ratios for any undetected putative companions. The observations are sensitive to companions with a maximum contrast of ~6^m^ at larger separations. At smaller separations, the mean (best) raw contrast at 2" is 3.8^m^ (6^m^), at 1" is 3.0^m^ (4.5^m^), and at 0.5" is 1.9^m^ (3^m^). Point-spread function subtraction can recover nearly the full contrast in the closer separations. For detected candidate binary pairs, we report separations, position angles, and relative magnitudes. Theoretical isochrones appropriate to the Pleiades and Praesepe clusters are then used to determine the corresponding binary mass ratios, which range from 0.2 to 0.9 in q=m_2_/m_1_. For our sample of roughly solar-mass (FGK type) stars in NGC 2264 and sub-solar-mass (K and early M-type) primaries in the Pleiades and Praesepe, the overall binary frequency is measured at ~15.5%+/-2%. However, this value should be considered a lower limit to the true binary fraction within the specified separation and mass ratio ranges in these clusters, given that complex and uncertain corrections for sensitivity and completeness have not been applied.
- ID:
- ivo://CDS.VizieR/J/AJ/156/259
- Title:
- Robo-AO detected close binaries in Gaia DR2
- Short Name:
- J/AJ/156/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Robo-AO survey of Kepler planetary candidate host stars, the largest adaptive optics survey yet performed, to measure the recovery rate of close stellar binaries in Gaia DR2 (Cat. I/345). We find that Gaia recovers binaries down to 1" at magnitude contrasts as large as six; closer systems are not resolved, regardless of secondary brightness. Gaia DR2 binary detection does not have a strong dependence on the orientation of the stellar pairs. We find 177 nearby stars to Kepler planetary candidate host stars in Gaia DR2 that were not detected in the Robo-AO survey, almost all of which are faint (G>20); the remainder were largely targets observed by Robo-AO in poor conditions. If the primary star is the host, the impact on the radii estimates of planet candidates in these systems is likely minimal; many of these faint stars, however, could be faint eclipsing binaries that are the source of a false positive planetary transit signal. With Robo-AO and Gaia combined, we find that 18.7+/-0.7% of Kepler planet candidate hosts have nearby stars within 4". We also find 36 nearby stars in Gaia DR2 around 35 planetary candidate host stars detected with K2. The nearby star fraction rate for K2 planetary candidates is significantly lower than that for the primary Kepler mission. The binary recovery rate of Gaia will improve initial radius estimates of future Transiting Exoplanet Survey Satellite planet candidates significantly; however, ground-based high-resolution follow-up observations are still needed for precise characterization and confirmation. The sensitivity of Gaia to closely separated binaries is expected to improve in later data releases.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/34
- Title:
- Robo-AO Kepler asteroseismic survey. II.
- Short Name:
- J/ApJ/888/34
- Date:
- 25 Oct 2021 10:08:41
- Publisher:
- CDS
- Description:
- The Kepler Space Telescope observed over 15000 stars for asteroseismic studies. Of these, 75% of dwarfs (and 8% of giants) were found to show anomalous behavior, such as suppressed oscillations (low amplitude) or no oscillations at all. The lack of solar-like oscillations may be a consequence of multiplicity, due to physical interactions with spectroscopic companions or due to the dilution of oscillation amplitudes from "wide" (AO detected; visual) or spectroscopic companions introducing contaminating flux. We present a search for stellar companions to 327 of the Kepler asteroseismic sample, which were expected to display solar-like oscillations. We used direct imaging with Robo-AO, which can resolve secondary sources at ~0.15", and followed up detected companions with Keck AO. Directly imaged companion systems with both separations of <=0.5" and amplitude dilutions >10% all have anomalous primaries, suggesting these oscillation signals are diluted by a sufficient amount of excess flux. We also used the high-resolution spectrometer ESPaDOnS at the Canada-France-Hawai'i Telescope to search for spectroscopic binaries. We find tentative evidence for a higher fraction of spectroscopic binaries with high radial velocity scatter in anomalous systems, which would be consistent with previous results suggesting that oscillations are suppressed by tidal interactions in close eclipsing binaries.
- ID:
- ivo://CDS.VizieR/J/AJ/152/18
- Title:
- Robo-AO Kepler planetary candidate survey. II.
- Short Name:
- J/AJ/152/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We initiated the Robo-AO Kepler Planetary Candidate Survey in 2012 to observe each Kepler exoplanet candidate host star with high angular resolution, visible light, laser adaptive optics (AOs) imaging. Our goal is to find nearby stars lying in Kepler's photometric apertures that are responsible for the relatively high probability of false-positive exoplanet detections and that cause underestimates of the size of transit radii. Our comprehensive survey will also shed light on the effects of stellar multiplicity on exoplanet properties and will identify rare exoplanetary architectures. In this second part of our ongoing survey, we observed an additional 969 Kepler planet candidate hosts and we report blended stellar companions up to {Delta}m{approx}6 that contribute to Kepler's measured light curves. We found 203 companions within ~4'' of 181 of the Kepler stars, of which 141 are new discoveries. We measure the nearby star probability for this sample of Kepler planet candidate host stars to be 10.6%+/-1.1% at angular separations up to 2.5'', significantly higher than the 7.4%+/-1.0% probability discovered in our initial sample of 715 stars; we find the probability increases to 17.6%+/-1.5% out to a separation of 4.0''. The median position of Kepler Objects of Interest (KOIs) observed in this survey are 1.1{deg} closer to the galactic plane, which may account for some of the nearby star probability enhancement. We additionally detail 50 Keck AO images of Robo-AO observed KOIs in order to confirm 37 companions detected at a <5{sigma} significance level and to obtain additional infrared photometry on higher significance detected companions.
- ID:
- ivo://CDS.VizieR/J/AJ/153/66
- Title:
- Robo-AO Kepler Planetary Candidate Survey. III.
- Short Name:
- J/AJ/153/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results of our search for stars nearby 1629 Kepler planet candidate hosts. With survey sensitivity to objects as close as ~0.15", and magnitude differences {Delta}m=<6, we find 223 stars in the vicinity of 206 target KOIs; 209 of these nearby stars have not been previously imaged in high resolution. We measure an overall nearby-star probability for Kepler planet candidates of 12.6%+/-0.9% at separations between 0.15" and 4.0". Particularly interesting KOI systems are discussed, including 26 stars with detected companions that host rocky, habitable zone candidates and five new candidate planet-hosting quadruple star systems. We explore the broad correlations between planetary systems and stellar binarity, using the combined data set of Baranec et al. (2016, J/AJ/152/18) and this paper. Our previous 2{sigma} result of a low detected nearby star fraction of KOIs hosting close-in giant planets is less apparent in this larger data set. We also find a significant correlation between detected nearby star fraction and KOI number, suggesting possible variation between early and late Kepler data releases.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/4
- Title:
- Robo-AO observations of binary stars
- Short Name:
- J/ApJ/799/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conducted a survey of nearby binary systems composed of main sequence stars of spectral types F and G in order to improve our understanding of the hierarchical nature of multiple star systems. Using Robo-AO, the first robotic adaptive optics instrument, we collected high angular resolution images with deep and well-defined detection limits in the Sloan Digital Sky Survey i' band. A total of 695 components belonging to 595 systems were observed. We prioritized observations of faint secondary components with separations over 10" to quantify the still poorly constrained frequency of their subsystems. Of the 214 secondaries observed, 39 contain such subsystems; 19 of those were discovered with Robo-AO. The selection-corrected frequency of secondary subsystems with periods from 10^3.5^ to 10^5^ days is 0.12+/-0.03, the same as the frequency of such companions to the primary. Half of the secondary pairs belong to quadruple systems where the primary is also a close pair, showing that the presence of subsystems in both components of the outer binary is correlated. The relatively large abundance of 2+2 quadruple systems is a new finding, and will require more exploration of the formation mechanism of multiple star systems. We also targeted close binaries with periods less than 100 yr, searching for their distant tertiary components, and discovered 17 certain and 2 potential new triples. In a subsample of 241 close binaries, 71 have additional outer companions. The overall frequency of tertiary components is not enhanced, compared to all (non-binary) targets, but in the range of outer periods from 10^6^ to 10^7.5^ days (separations on the order of 500AU), the frequency of tertiary components is 0.16+/-0.03, exceeding the frequency of similar systems among all targets (0.09) by almost a factor of two. Measurements of binary stars with Robo-AO allowed us to compute first orbits for 9 pairs and to improve orbits of another 11 pairs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/S138
- Title:
- Robotic view of 67P perihelion
- Short Name:
- J/MNRAS/462/S138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Around the time of its perihelion passage, the observability of 67P/Churyumov-Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where service/queue-scheduled mode was possible, and with robotic telescopes. We describe the robotic observations that allowed us to measure the total activity of the comet around perihelion, via photometry (dust) and spectroscopy (gas), and compare these results with the measurements at this time by Rosetta's instruments. The peak of activity occurred approximately two weeks after perihelion. The total brightness (dust) largely followed the predictions from Snodgrass et al., with no significant change in total activity levels from previous apparitions. The CN gas production rate matched previous orbits near perihelion, but appeared to be relatively low later in the year.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A38
- Title:
- Robust automatic photometry for SDSS gal.
- Short Name:
- J/A+A/591/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an automatic procedure to perform reliable photometry of galaxies on SDSS images. We selected a sample of 5853 galaxies in the Coma and Virgo superclusters. For each galaxy, we derive Petrosian g and i magnitudes, surface brightness and color profiles. Unlike the SDSS pipeline, our procedure is not affected by the well known shredding problem and efficiently extracts Petrosian magnitudes for all galaxies. Hence we derived magnitudes even from the population of galaxies missed by the SDSS which represents ~25% of all Local supercluster galaxies and 95% of galaxies with g<11mag. After correcting the g and i magnitudes for Galactic and internal extinction, the blue and red sequences in the color magnitude diagram are well separated, with similar slopes. In addition, we study (i) the color-magnitude diagrams in different galaxy regions, the inner (r<=1kpc), intermediate (0.2R_{Pet}_>=r>=0.3R_{Pet}_) and outer, disk-dominated (r>=0.35R_{Pet}_)) zone, and (ii), we compute template color profiles, discussing the dependences of the templates on the galaxy masses and on their morphological type. The two analyses consistently lead to a picture where elliptical galaxies show no color gradients, irrespective of their masses. Spirals, instead, display a steeper gradient in their color profiles with increasing mass, which is consistent with the growing relevance of a bulge and/or a bar component above 10^10^M_{sun}_.
