6 research outputs found

    Detection and Preliminary Characterisation of Polluted White Dwarfs from Gaia EDR3 and LAMOST

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    We present a catalogue of 62 polluted white dwarfs observed by the 9th Low-Resolution Data Release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST LRS DR9v1; R≈\approx1,800) and the Early Data Release 3 (EDR3) of the Gaia Mission. Among these stellar remnants, 30 are new discoveries with previously unknown traces of calcium pollution. To generate our catalogue, we used a database of 4,324 unique Gaia EDR3 white dwarf candidates with LAMOST LRS DR9v1 observations, many of which have been spectroscopically confirmed by other telescopes. For these stars, we developed a quantitative method to detect calcium absorption in their spectra between 3,900-4,000A˚\mathring {\mathrm A}, which we then validated through visual inspection and multiple literature cross-checks. Our catalogue provides the astrometric and photometric properties of the white dwarf candidates, incorporates supplementary data (e.g. Montreal White Dwarf Database, MWDD; PanSTARRS; the Hubble Space Telescope), and indicates the possibility of calcium pollution in their atmospheres. For our final sample of polluted white dwarfs, we also determine the main atmospheric properties of 23 sources with effective temperatures TeffT_{\rm eff}≤\leq25,000K and no existing calcium abundances in the MWDD. Our analysis represents a first step towards measuring the full atmospheric composition of these stars and learning about the bulk properties of their accreted material. As we venture into the era of wide-field spectroscopic surveys, our work highlights the importance of combining large-scale databases for identifying and characterising new polluted white dwarfs.Comment: 29 pages, 14 figures (+3 in the Appendix), 5 tables (+5 in the Appendix). Accepted for publication in MNRA

    HD 219134 Revisited: Planet d Transit Upper Limit and Planet f Transit Nondetection with ASTERIA and TESS

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    HD 219134 is a K3V dwarf star with six reported radial-velocity discovered planets. The two innermost planets b and c show transits, raising the possibility of this system to be the nearest (6.53 pc), brightest (V = 5.57) example of a star with a compact multiple transiting planet system. Ground-based searches for transits of planets beyond b and c are not feasible because of the infrequent transits, long transit duration (~5 hr), shallow transit depths (<1%), and large transit time uncertainty (~half a day). We use the space-based telescopes the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) and the Transiting Exoplanet Survey Satellite (TESS) to search for transits of planets f (P = 22.717 days and M sin i = 7.3 ± 0.04M_⊕) and d (P = 46.859 days and M sin i = 16.7 ± 0.64M_⊕). ASTERIA was a technology demonstration CubeSat with an opportunity for science in an extended program. ASTERIA observations of HD 219134 were designed to cover the 3σ transit windows for planets f and d via repeated visits over many months. While TESS has much higher sensitivity and more continuous time coverage than ASTERIA, only the HD 219134 f transit window fell within the TESS survey's observations. Our TESS photometric results definitively rule out planetary transits for HD 219134 f. We do not detect the Neptune-mass HD 219134 d transits and our ASTERIA data are sensitive to planets as small as 3.6 R_⊕. We provide TESS updated transit times and periods for HD 219134 b and c, which are designated TOI 1469.01 and 1469.02 respectively

    HD 191939: Three Sub-Neptunes Transiting a Sun-like Star Only 54 pc Away

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    We present the discovery of three sub-Neptune-sized planets transiting the nearby and bright Sun-like star HD 191939 (TIC 269701147, TOI 1339), a K s = 7.18 mag G8 V dwarf at a distance of only 54 pc. We validate the planetary nature of the transit signals by combining 5 months of data from the Transiting Exoplanet Survey Satellite with follow-up ground-based photometry, archival optical images, radial velocities, and high angular resolution observations. The three sub-Neptunes have similar radii (Rb=3.42-0.11+0.11, Rc=3.23-0.11+0.11, and Rd=3.16-0.11+0.11,R⊕), and their orbits are consistent with a stable, circular, and coplanar architecture near mean-motion resonances of 1:3 and 3:4 (P b = 8.88, P c = 28.58, and P d = 38.35 days). The HD 191939 system is an excellent candidate for precise mass determinations of the planets with high-resolution spectroscopy due to the host star's brightness and low chromospheric activity. Moreover, the system's compact and near-resonant nature can provide an independent way to measure planetary masses via transit timing variations while also enabling dynamical and evolutionary studies. Finally, as a promising target for multiwavelength transmission spectroscopy of all three planets' atmospheres, HD 191939 can offer valuable insight into multiple sub-Neptunes born from a protoplanetary disk that may have resembled that of the early Sun.Funding for this research is provided by the Massachusetts Institute of Technology, the MIT Torres Fellow Program, and the MIT Kavli Institute. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and the TESS Science Processing Operations Center. Funding for the TESS mission is provided by NASAʼs Science Mission directorate. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes (MAST). The STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. The National Geographic Society—Palomar Observatory Sky Atlas (POSS-I) was made by the California Institute of Technology with grants from the National Geographic Society. The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www. cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/ gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This paper used data retrieved from the SOPHIE archive at Observatoire de Haute-Provence (OHP), available at atlas.obs-hp.fr/sophie. The AO images presented in this paper were obtained at the Gemini Observatory (Program ID: GN-2019B-LP-101), which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). The authors thank Amanda Bosh (MIT), Tim Brothers (MIT Wallace Astrophysical Observatory), Julien de Wit (MIT), Artem Burdanov (MIT), Songhu Wang (Yale University), Enrique Herrero (IEEC/OAdM), Jonathan Irwin (HarvardCfA), Samuel Hadden (Harvard-CfA), Özgür Baştürk (Ankara University), Ergün Ege (Istanbul University), and Brice-Olivier Demory (University of Bern) for helping to coordinate followup observations. We thank the anonymous referee for helpful comments and suggestions that greatly improved this work. M.N.G. and C.X.H. acknowledge support from MIT’s Kavli Institute as Juan Carlos Torres Fellows. T.D. acknowledges support from MITʼs Kavli Institute as a Kavli postdoctoral fellow. A.V.ʼs work was performed under contract with the California Institute of Technology/Jet Propulsion Laboratory, funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. I.R. acknowledges support from the Spanish Ministry of Science, Innovation and Universities (MCIU) and the Fondo Europeo de Desarrollo Regional (FEDER) through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA program. B.V.R. and J.N.W. thank the Heising-Simons Foundation for support. I.J.M.C. acknowledges support from the NSF through grant AST-1824644 and NASA through Caltech/JPL grant RSA-1610091

    Hide your pain:Social threat increases pain reports and aggression, but reduces facial pain expression and empathy

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    Earlier research studying the effects of social threat on the experience and expression of pain led to mixed results. In this study, female participants (N = 32) came to the lab with two confederates. Both confederates administered a total of 10 painful electrocutaneous stimuli to the participant. The framing of the administration was manipulated in a within-subjects design: In the low social threat condition the participant was told that the confederate could choose between 10 to 20 pain stimuli, thus they believed that this confederate chose to administer the minimum allowed number of pain stimuli. In the high social threat condition the confederate had a choice between 1 and 10 stimuli, thus they believed that this confederate chose to administer the maximum allowed number of stimuli. Participants reported on the intensity, unpleasantness, and threat value of the painful stimuli, and their facial expression was recorded. Moreover, aggression and empathy towards the confederates were assessed. As hypothesized, participants reported increased pain intensity, unpleasantness, and threat in the high social threat condition compared to the low social threat condition, but showed less facial pain expression. Finally, participants exhibited increased aggression and reduced empathy towards the confederate in the high social threat condition.status: publishe

    HD 191939: Three Sub-Neptunes Transiting a Sun-like Star Only 54 pc Away

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