- ID:
- ivo://CDS.VizieR/J/AJ/160/111
- Title:
- RI light curve of KELT-25 and KELT-26
- Short Name:
- J/AJ/160/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A stars. The transit signals were initially detected by the KELT survey and subsequently confirmed by Transiting Exoplanet Survey Satellite (TESS) photometry. KELT-25b is on a 4.40day orbit around the V=9.66 star CD-245016 (Teff=8280_-180_^+440^K, M{star}=2.18_-0.11_^+0.12^M{sun}), while KELT-26b is on a 3.34day orbit around the V=9.95 star HD134004 (Teff=8640_-240_^+500^K, M{star}=1.93_-0.16_^+0.14^M{sun}), which is likely an Am star. We have confirmed the substellar nature of both companions through detailed characterization of each system using ground-based and TESS photometry, radial velocity measurements, Doppler tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of RP=1.64_-0.043_^+0.039^RJ and a 3{sigma} upper limit on the companion's mass of ~64MJ. For KELT-26b, we infer a planetary mass and radius of MP=1.41_-0.51_^+0.43^M_J_ and RP=1.94_-0.058_^+0.060^RJ. From Doppler tomographic observations, we find KELT-26b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the TESS data. KELT-25b appears to be in a well-aligned, prograde orbit, and the system is likely a member of the cluster Theia449.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/763/L27
- Title:
- RI light curves of the type IIn SN 2009ip
- Short Name:
- J/ApJ/763/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent observations by Mauerhan et al. (2013MNRAS.430.1801M) have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN explosion. We present ~100 optical R- and I-band photometric measurements of SN 2009ip obtained between UT 2012 September 23.6 and October 9.6, using 0.3-0.4m aperture telescopes from the Coral Towers Observatory in Cairns, Australia. The light curves show well-defined phases, including very rapid brightening early on (0.5mag in 6hr observed during the night of September 24), a transition to a much slower rise between September 25 and September 28, and a plateau/peak around October 7. These changes are coincident with the reported spectroscopic changes that most likely mark the start of a strong interaction between the fast SN ejecta and a dense circumstellar medium formed during the LBV eruptions observed in recent years. In the 16-day observing period, SN 2009ip brightened by 3.7mag from I=17.4mag on September 23.6 (M_I_=~-14.2) to I=13.7mag (M_I_=~-17.9) on October 9.6, radiating ~3x10^49^erg in the optical wavelength range. As of 2012 October 9.6, SN 2009ip is more luminous than most Type IIP SN and comparable to other Type IIn SN.
- ID:
- ivo://CDS.VizieR/J/A+A/416/125
- Title:
- RI photometry in alpha Per and Pleiades
- Short Name:
- J/A+A/416/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photographic astrometry (proper motions and accurate positions), photometry (in the photographic R and I passbands) and membership probabilities for high probability proper motion members of the clusters Alpha Persei and The Pleiades are presented, along with cross-identifications with names from previously known members in the compilation of Prosser & Stauffer (The Stauffer & Prosser Open Cluster Catalogue, priv.comm.) and their corresponding proper motion membership probabilities according to our study. The SuperCOSMOS facility at the Royal Observatory Edinburgh has (using plates from the United Kingdom Schmidt Telescope) produced complete southern sky surveys in BJ, R and I with an additional second epoch R survey. These surveys are now publicly available (Hambly et al. 2001MNRAS.326.1279H). The scanning program has now moved on to the northern hemisphere, using film and glass copies of plates taken by the Oschin Schmidt Telescope on Mount Palomar, California. These data will soon be publicly available.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/155
- Title:
- RI photometry of blazars S5 0716+714 and 3C 273
- Short Name:
- J/ApJ/880/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the photometric observations of blazars S5 0716+714 and 3C 273 with high temporal resolution (30-60s) in the I or R bands. The observations were performed with a 1.02m optical telescope from 2007 March 7 to 2012 May 16. The F-test, one-way analysis of variance (ANOVA) test, and z-transformed discrete correlation function (ZDCF) cross-correlation zero lag test are used to search for intra-day variability (IDV). Four and five reliable IDVs survive three tests for S5 0716+714 and 3C 273, respectively. IDVs are found for S5 0716+714 and 3C 273. A flare on 2008 May 8 has {Delta}I~0.06+/-0.01mag in a duration of 0.54hr for S5 0716+714. A flare on 2011 May 10 shows {Delta}R~0.05+/-0.01mag in a duration of 0.40hr for 3C 273. Sharp dips appear on 2011 May 9 for 3C 273 and show {Delta}R~0.05+/-0.01mag. Under the assumptions that the IDV is tightly connected to black hole mass, M*, and that the flare durations are representative of the minimum characteristic timescales, we can estimate upper bounds to M*. In the case of the Kerr black holes, M*<~10^8.91^M_{sun}_ and M*<~10^9.02^M_{sun}_ are given for S5 0716+714 and 3C 273, respectively. These mass measurements are consistent with those measurements reported in the literature. Also, we discuss the origins of optical variations found in this work.
- ID:
- ivo://CDS.VizieR/J/ApJS/94/749
- Title:
- RI photometry of cool dwarfs
- Short Name:
- J/ApJS/94/749
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The luminosity function at the end of the main sequence is determined from V, R, and I data taken by the CCD/Transit Instrument (CTI), a dedicated telescope surveying an 8.25' wide strip of sky centered at {delta}=+28{deg}, thus sampling Galactic latitudes of +90{deg} down to -35{deg}. A selection of 133 objects chosen via R-I and V-I colors has been observed spectroscopically at the 4.5m Multiple Mirror Telescope to assess contributions by giants and subdwarfs and to verify that the reddest targets are objects of extremely late spectral class. Eighteen dwarfs of type M6 or later have been discovered, with the latest being of type M8.5. Data used for the determination of the luminosity function cover 27.3{deg}^2^ down to a completeness limit of R=19.0.
- ID:
- ivo://CDS.VizieR/J/A+A/369/932
- Title:
- RI photometry of LMC carbon stars
- Short Name:
- J/A+A/369/932
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of 7760 carbon stars in the Large Magellenic Cloud is presented. The stars were identified during a systematic survey of objective-prism plates taken with the UK 1.2m Schmidt Telescope. The catalogue is compared with other lists of carbon stars and the distribution of the carbon stars is discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/417/479
- Title:
- RI photometry of NGC 185 carbon stars
- Short Name:
- J/A+A/417/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the CFH12K wide field camera to survey the carbon star population of NGC 185 using the CN-TiO technique. 145 C stars are identified with a mean <I>=19.99+/-0.05, corresponding to <M_I_>=-4.41+/-0.05, a mean luminosity similar to what was recently found for the C star population of NGC 147. The stellar surface density profile of NGC 185 follows a power law with an exponential scale length of 2.53+/-0.07'. The surface density of C stars follows also a power law but with a smaller scale length, 1.56+/-0.06, demonstrating that the intermediate-age population of NGC 185 is more concentrated than its old population. A tidal radius, r_t_=22.5+/-2.2' is determined from red giant star counts. The C/M ratio of NGC 185 is 0.17+/-0.02 with no apparent sign of a radial gradient. We compare the carbon star populations of NGC 185 and NGC 147 to conclude that it is unlikely that they form a close pair.
- ID:
- ivo://CDS.VizieR/J/AJ/125/3037
- Title:
- RI photometry of NGC 205 carbon stars
- Short Name:
- J/AJ/125/3037
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a CFH12K survey of the carbon stars in NGC 205 and its surrounding field. We find that the number of C stars in NGC 205 is low (~500) for its luminosity and that very few C stars are seen outside of the 10 isophote, suggesting tidal stripping by M31. Their <M_I_>=-4.54, a magnitude nearly identical to what has been found in other galaxies with numerous C stars. Stars with accurate (R-I) photometry, to I~22.5, are used to determine the outer profile of NGC 205.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/19
- Title:
- riz photometry in Cyg OB2
- Short Name:
- J/ApJS/202/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to fully understand the gravitational collapse of molecular clouds, the star formation process, and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of stellar contents and positions in the Galaxy. The young massive association Cygnus OB2, in the Cygnus-X region, is a unique target to study how star formation and the evolution of circumstellar disks proceed in the presence of a large number of massive stars. We present a catalog obtained with recent optical observations in the r, i, z filters with OSIRIS, mounted on the 10.4m Gran Telescopio CANARIAS telescope, which is the deepest optical catalog of CygOB2 to date. The catalog consists of 64,157 sources down to M=0.15M_{sun}_ at the adopted distance and age of Cyg OB2. A total of 38,300 sources have good photometry in all three bands. We combined the optical catalog with existing X-ray data of this region, in order to define the cluster locus in the optical diagrams. The cluster locus in the r-i versus i-z diagram is compatible with an extinction of the optically selected cluster members in the 2.64m<A_V_<5.57m range. We derive an extinction map of the region, finding a median value of A_V_=4.33m in the center of the association, decreasing toward the northwest. In the color-magnitude diagrams, the shape of the distribution of main-sequence stars is compatible with the presence of an obscuring cloud in the foreground ~850+/-25pc from the Sun.
- 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.
