- ID:
- ivo://CDS.VizieR/J/AJ/145/5
- Title:
- Follow-up photometry of HATS-1
- Short Name:
- J/AJ/145/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-1b, a transiting extrasolar planet orbiting the moderately bright V=12.05 G dwarf star GSC 6652-00186, and the first planet discovered by HATSouth, a global network of autonomous wide-field telescopes. HATS-1b has a period of P{approx}3.4465days, mass of M_p_{approx}1.86M_J_, and radius of R_p_{approx}1.30R_J_. The host star has a mass of 0.99M_{sun}_ and radius of 1.04R_{sun}_. The discovery light curve of HATS-1b has near-continuous coverage over several multi-day timespans, demonstrating the power of using a global network of telescopes to discover transiting planets.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/834/107
- Title:
- Follow-up photometry of M101 OT2015-1
- Short Name:
- J/ApJ/834/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient in the Pinwheel galaxy (M101), spanning a total of 16 years. The light curve showed two distinct peaks with absolute magnitudes M_r_<=-12.4 and M_r_~-12, on 2014 November 11 and 2015 February 17, respectively. The spectral energy distributions during the second maximum show a cool outburst temperature of ~3700K and low expansion velocities (~-300km/s) for the HI, CaII, BaII, and KI lines. From archival data spanning 15-8 years before the outburst, we find a single source consistent with the optically discovered transient, which we attribute to being the progenitor; it has properties consistent with being an F-type yellow supergiant with L~8.7x10^4^L_{sun}_, T_eff_~7000K, and an estimated mass of M1=18+/-1M_{sun}_. This star has likely just finished the H-burning phase in the core, started expanding, and is now crossing the Hertzsprung gap. Based on the combination of observed properties, we argue that the progenitor is a binary system, with the more evolved system overfilling the Roche lobe. Comparison with binary evolution models suggests that the outburst was an extremely rare phenomenon, likely associated with the ejection of the common envelope of a massive star. The initial mass of the primary fills the gap between the merger candidates V838 Mon (5-10M_{sun}_) and NGC 4490-OT (30M_{sun}_).
- ID:
- ivo://CDS.VizieR/J/ApJ/874/82
- Title:
- Follow-up photometry & spectroscopy of PTF14jg
- Short Name:
- J/ApJ/874/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the outbursting source PTF 14jg, which, prior to the onset of its late 2013 eruption, was a faint, unstudied, and virtually uncataloged star. The salient features of the PTF 14jg outburst are (i) projected location near the W4 HII region and radial velocity consistent with physical association; (ii) a light curve that underwent an ~6-7mag optical (R-band) through mid-infrared (L-band) brightening on a timescale of a few months, peaked and then faded by ~3mag, but plateaued still >3.5mag above quiescence by ~8 months post-peak, lasting to at least 4yr after eruption; (iii) strong outflow signatures with velocities reaching -530km/s; (iv) a low-gravity and broad (~100-150km/s FWHM) optical absorption-line spectrum that systematically changes its spectral type with wavelength; (v) lithium; and (vi) ultraviolet and infrared excess. We tentatively identify the outburst as exhibiting characteristics of a young star FU Ori event. However, the burst would be unusually hot, with an absorption spectrum exhibiting high-excitation (~11000-15000K) lines in the optical and no evidence of CO in the near-infrared, in addition to exhibiting an unusual light curve. We thus also consider alternative scenarios-including various forms of novae, nuclear-burning instabilities, massive star events, and mergers-finding them all inferior to the atypically hot FU Ori star classification. The source eventually may be interpreted as a new category of young star outburst with a larger amplitude and shorter rise time than most FU Ori-like events.
614. Fornax Globular 3
- ID:
- ivo://CDS.VizieR/J/AJ/114/1471
- Title:
- Fornax Globular 3
- Short Name:
- J/AJ/114/1471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new B-V color-magnitude diagrams for Fornax globular cluster 3 and the surrounding field where our data reach one magnitude below the horizontal branch which is at V_HB_=21.28. After subtracting the field stars from the cluster CMD, we found no evidence for an intrinsic width of the red giant branch because the scatter is only slightly wider than the photometric errors. We determine that there is an intrinsic width to the horizontal branch because the scatter is larger than the photometric errors. After comparing our data with earlier photometry, we find 7 possible variable stars, both within and outside the instability strip, out of a total of 74 horizontal branch stars. We calculate the horizontal branch type of cluster 3 to be of intermediate color, -0.110+/-0.104, which when compared to Fornax cluster 1, having similar metallicity, suggests a second-parameter pair. Five carbon star candidates identified by Jorgensen & Jimenez (1997, Cat. <J/A+A/317/54>) are marked in the field-subtracted color-magnitude diagram. (c) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/J/A+A/440/61
- Title:
- FORS spectroscopy of HDFS galaxies
- Short Name:
- J/A+A/440/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present low resolution multi-object spectroscopy of an I-band magnitude limited (I_AB_~23-23.5) sample of galaxies located in an area centered on the Hubble Deep Field-South (HDFS). The observations were obtained using the Focal Reducer/low dispersion Spectrograph (FORS) on the ESO Very Large Telescope. Thirty-two primary spectroscopic targets in the HST-WFPC2 HDFS were supplemented with galaxies detected in the Infrared Space Observatory's survey of the HDFS and the ESO Imaging Deep Survey to comprise a sample of 100 galaxies for spectroscopic observations. Based on detections of several emission lines, such as [OII]3727, H{beta} and [OIII]5007, or of other spectroscopic features, we measured accurate redshifts for 50 objects in the central HDFS and flanking fields. The redshift range of the current sample of galaxies is 0.6-1.2, with a median redshift of 1.13 (at I~23.5 not corrected for completeness). The sample is dominated by starburst galaxies with only a small fraction of ellipticals (~10%). For the emission line objects, the extinction corrected [OII]3727 line strengths yield estimates of star formation rates in the range 0.5-30M_{sun}_/yr. We used the present data to derive the [OII]3727 luminosity function up to redshift of 1.2. When combined with [OII]3727 luminosity densities for the local and high redshift Universe, our results confirm the steep rise in the star formation rate (SFR) to z~1.3.
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/4307
- Title:
- From optical to infrared photometry of SN 2013dy
- Short Name:
- J/MNRAS/452/4307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SN 2013dy is a Type Ia supernova (SN Ia) for which we have compiled an extraordinary data set spanning from 0.1 to ~500d after explosion. We present 10 epochs of ultraviolet (UV) through near-infrared (NIR) spectra with Hubble Space Telescope/Space Telescope Imaging Spectrograph, 47 epochs of optical spectra (15 of them having high resolution), and more than 500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and slowly declining light curve ({Delta}m_15_(B)=0.92mag), shallow SiII {lambda}6355 absorption, and a low velocity gradient. We detect strong CII in our earliest spectra, probing unburned progenitor material in the outermost layers of the SN ejecta, but this feature fades within a few days. The UV continuum of SN 2013dy, which is strongly affected by the metal abundance of the progenitor star, suggests that SN 2013dy had a relatively high-metallicity progenitor. Examining one of the largest single set of high-resolution spectra for an SN Ia, we find no evidence of variable absorption from circumstellar material. Combining our UV spectra, NIR photometry, and high-cadence optical photometry, we construct a bolometric light curve, showing that SN 2013dy had a maximum luminosity of 10.0^+4.8^_-3.8_x10^42^erg/s. We compare the synthetic light curves and spectra of several models to SN 2013dy, finding that SN 2013dy is in good agreement with a solar-metallicity W7 model.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/585
- Title:
- Fundamental parameters of M dwarfs
- Short Name:
- J/MNRAS/389/585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We empirically determine effective temperatures and bolometric luminosities for a large sample of nearby M dwarfs, for which high accuracy optical and infrared photometry is available. We introduce a new technique which exploits the flux ratio in different bands as a proxy of both effective temperature and metallicity. Our temperature scale for late-type dwarfs extends well below 3000K (almost to the brown dwarf limit) and is supported by interferometric angular diameter measurements above 3000K. Our metallicities are in excellent agreement (usually within 0.2dex) with recent determinations via independent techniques. A subsample of cool M dwarfs with metallicity estimates based on hotter Hipparcos common proper motion companions indicates our metallicities are also reliable below 3000K, a temperature range unexplored until now. The high quality of our data allows us to identify a striking feature in the bolometric luminosity versus temperature plane, around the transition from K to M dwarfs. We have compared our sample of stars with theoretical models and conclude that this transition is due to an increase in the radii of the M dwarfs, a feature which is not reproduced by theoretical models.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A131
- Title:
- Fundamental parameters of star clusters in the LMC
- Short Name:
- J/A+A/555/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To enlarge our growing sample of well-studied star clusters in the Large Magellanic Cloud (LMC), we present CCD Washington CT1 photometry to T1~23 in the fields of twenty-three mostly unstudied clusters located in the inner disc and outer regions of the LMC. We estimated cluster radii from star counts. Using the cluster Washington (T1,C-T1) colour-magnitude diagrams, statistically cleaned from field star contamination, we derived cluster ages and metallicities from a comparison with theoretical isochrones of the Padova group. Whenever possible, we also derived ages using delta T1 - the magnitude difference between the red giant clump and the main sequence turn off - and estimated metallicities from the standard giant branch procedure. We enlarged our sample by adding clusters with published ages and metallicities determined on a similar scale by applying the same methods. We examined relationships between their positions in the LMC, ages and metallicities. We find that the two methods for age and metallicity determination agree well with each other. Fourteen clusters are found to be intermediate-age clusters (1-2Gyr), with [Fe/H] values ranging from -0.4 to -0.7. The remaining nine clusters turn out to be younger than 1Gyr, with metallicities between 0.0 and -0.4. Our 23 clusters represent an increase of ~30% in the current total amount number of well-studied LMC clusters using Washington photometry. In agreement with previous studies, we find no evidence for a metallicity gradient. We also find that the younger clusters were formed closer to the LMC centre than the older ones.
- ID:
- ivo://CDS.VizieR/J/AJ/155/30
- Title:
- Fundamental parameters of 87 stars from the NPOI
- Short Name:
- J/AJ/155/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the fundamental properties of 87 stars based on angular diameter measurements from the Navy Precision Optical Interferometer, 36 of which have not been measured previously using interferometry. Our sample consists of 5 dwarfs, 3 subgiants, 69 giants, 3 bright giants, and 7 supergiants, and span a wide range of spectral classes from B to M. We combined our angular diameters with photometric and distance information from the literature to determine each star's physical radius, effective temperature, bolometric flux, luminosity, mass, and age.
- ID:
- ivo://CDS.VizieR/J/AJ/154/259
- Title:
- Fundamental parameters of Tycho-2 & TGAS stars
- Short Name:
- J/AJ/154/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present bolometric fluxes and angular diameters for over 1.6 million stars in the Tycho-2 catalog (I/259), determined using previously determined empirical color-temperature and color-flux relations. We vet these relations via full fits to the full broadband spectral energy distributions for a subset of benchmark stars and perform quality checks against the large set of stars for which spectroscopically determined parameters are available from LAMOST, RAVE, and/or APOGEE. We then estimate radii for the 355502 Tycho-2 stars in our sample whose Gaia DR1 (I/337) parallaxes are precise to ~<10%. For these stars, we achieve effective temperature, bolometric flux, and angular diameter uncertainties of the order of 1%-2% and radius uncertainties of order 8%, and we explore the effect that imposing spectroscopic effective temperature priors has on these uncertainties. These stellar parameters are shown to be reliable for stars with T_eff_~<7000 K. The over half a million bolometric fluxes and angular diameters presented here will serve as an immediate trove of empirical stellar radii with the Gaia second data release, at which point effective temperature uncertainties will dominate the radius uncertainties. Already, dwarf, subgiant, and giant populations are readily identifiable in our purely empirical luminosity-effective temperature (theoretical) Hertzsprung-Russell diagrams.
