Browsing by Author "Kurtovic, Nicolas T."

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    An ultrahot Neptune in the Neptune desert
    (2020) Jenkins, James S.; Diaz, Matias R.; Kurtovic, Nicolas T.; Espinoza, Nestor; Vines, Jose I.; Rojas, Pablo A. Pena; Brahm, Rafael; Torres, Pascal; Cortes-Zuleta, Pia; Soto, Maritza G.; Lopez, Eric D.; King, George W.; Wheatley, Peter J.; Winn, Joshua N.; Ciardi, David R.; Ricker, George; Vanderspek, Roland; Latham, David W.; Seager, Sara; Jenkins, Jon M.; Beichman, Charles A.; Bieryla, Allyson; Burke, Christopher J.; Christiansen, Jessie L.; Henze, Christopher E.; Klaus, Todd C.; McCauliff, Sean; Mori, Mayuko; Narita, Norio; Nishiumi, Taku; Tamura, Motohide; de Leon, Jerome Pitogo; Quinn, Samuel N.; Villasenor, Jesus Noel; Vezie, Michael; Lissauer, Jack J.; Collins, Karen A.; Collins, Kevin I.; Isopi, Giovanni; Mallia, Franco; Ercolino, Andrea; Petrovich, Cristobal; Jordan, Andres; Acton, Jack S.; Armstrong, David J.; Bayliss, Daniel; Bouchy, Francois; Belardi, Claudia; Bryant, Edward M.; Burleigh, Matthew R.; Cabrera, Juan; Casewell, Sarah L.; Chaushev, Alexander; Cooke, Benjamin F.; Eigmueller, Philipp; Erikson, Anders; Foxell, Emma; Gansicke, Boris T.; Gill, Samuel; Gillen, Edward; Guenther, Maximilian N.; Goad, Michael R.; Hooton, Matthew J.; Jackman, James A. G.; Louden, Tom; McCormac, James; Moyano, Maximiliano; Nielsen, Louise D.; Pollacco, Don; Queloz, Didier; Rauer, Heike; Raynard, Liam; Smith, Alexis M. S.; Tilbrook, Rosanna H.; Titz-Weider, Ruth; Turner, Oliver; Udry, Stephane; Walker, Simon. R.; Watson, Christopher A.; West, Richard G.; Palle, Enric; Ziegler, Carl; Law, Nicholas; Mann, Andrew W.
    About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet(1,2). All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (R-circle plus), or apparently rocky planets smaller than 2 R-circle plus. Such lack of planets of intermediate size (the `hot Neptune desert') has been interpreted as the inability of low-mass planets to retain any hydrogen/ helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 R-circle plus and a mass of 29 M-circle plus, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite(3) revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planet's mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0(-2.9)(+2.7) % of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this `ultrahot Neptune' managed to retain such an envelope. Follow-up observations of the planet's atmosphere to better understand its origin and physical nature will be facilitated by the star's brightness (V-mag = 9.8).
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    Molecules with ALMA at Planet-forming Scales (MAPS). I. Program Overview and Highlights
    (2021) Oberg, Karin, I; Guzman, Viviana V.; Walsh, Catherine; Aikawa, Yuri; Bergin, Edwin A.; Law, Charles J.; Loomis, Ryan A.; Alarcon, Felipe; Andrews, Sean M.; Bae, Jaehan; Bergner, Jennifer B.; Boehler, Yann; Booth, Alice S.; Bosman, Arthur D.; Calahan, Jenny K.; Cataldi, Gianni; Cleeves, L. Ilsedore; Czekala, Ian; Furuya, Kenji; Huang, Jane; Ilee, John D.; Kurtovic, Nicolas T.; Le Gal, Romane; Liu, Yao; Long, Feng; Menard, Francois; Nomura, Hideko; Perez, Laura M.; Qi, Chunhua; Schwarz, Kamber R.; Sierra, Anibal; Teague, Richard; Tsukagoshi, Takashi; Yamato, Yoshihide; van't Hoff, Merel L. R.; Waggoner, Abygail R.; Wilner, David J.; Zhang, Ke
    Planets form and obtain their compositions in dust- and gas-rich disks around young stars, and the outcome of this process is intimately linked to the disk chemical properties. The distributions of molecules across disks regulate the elemental compositions of planets, including C/N/O/S ratios and metallicity (O/H and C/H), as well as access to water and prebiotically relevant organics. Emission from molecules also encodes information on disk ionization levels, temperature structures, kinematics, and gas surface densities, which are all key ingredients of disk evolution and planet formation models. The Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program was designed to expand our understanding of the chemistry of planet formation by exploring disk chemical structures down to 10 au scales. The MAPS program focuses on five disks-around IM Lup, GM Aur, AS 209, HD 163296, and MWC 480-in which dust substructures are detected and planet formation appears to be ongoing. We observed these disks in four spectral setups, which together cover similar to 50 lines from over 20 different species. This paper introduces the Astrophysical Journal Supplement's MAPS Special Issue by presenting an overview of the program motivation, disk sample, observational details, and calibration strategy. We also highlight key results, including discoveries of links between dust, gas, and chemical substructures, large reservoirs of nitriles and other organics in the inner disk regions, and elevated C/O ratios across most disks. We discuss how this collection of results is reshaping our view of the chemistry of planet formation.
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    Molecules with ALMA at Planet-forming Scales (MAPS). II. CLEAN Strategies for Synthesizing Images of Molecular Line Emission in Protoplanetary Disks
    (2021) Czekala, Ian; Loomis, Ryan A.; Teague, Richard; Booth, Alice S.; Huang, Jane; Cataldi, Gianni; Ilee, John D.; Law, Charles J.; Walsh, Catherine; Bosman, Arthur D.; Guzman, Viviana V.; Gal, Romane Le; Oberg, Karin I.; Yamato, Yoshihide; Aikawa, Yuri; Andrews, Sean M.; Bae, Jaehan; Bergin, Edwin A.; Bergner, Jennifer B.; Cleeves, L. Ilsedore; Kurtovic, Nicolas T.; Menard, Francois; Nomura, Hideko; Perez, Laura M.; Qi, Chunhua; Schwarz, Kamber R.; Tsukagoshi, Takashi; Waggoner, Abygail R.; Wilner, David J.; Zhang, Ke
    The Molecules with ALMA at Planet-forming Scales Large Program (MAPS LP) surveyed the chemical structures of five protoplanetary disks across more than 40 different spectral lines at high angular resolution (0.'' 15 and 0.'' 30 beams for Bands 6 and 3, respectively) and sensitivity (spanning 0.3-1.3 mJy beam(-1) and 0.4-1.9 mJy beam(-1) for Bands 6 and 3, respectively). In this article, we describe the multistage workflow-built around the CASA tclean image deconvolution procedure-that we used to generate the core data product of the MAPS LP: the position-position-velocity image cubes for each spectral line. Owing to the expansive nature of the survey, we encountered a range of imaging challenges: some are familiar to the submillimeter protoplanetary disk community, like the need to use an accurate CLEAN mask, and others are less well known, like the incorrect default flux scaling of the CLEAN residual map first described by Jorsater & van Moorsel (the "JvM effect"). We distill lessons learned into recommended workflows for synthesizing image cubes of molecular emission. In particular, we describe how to produce image cubes with accurate fluxes via "JvM correction," a procedure that is generally applicable to any image synthesized via CLEAN deconvolution but is especially critical for low signal-to-noise ratio (S/N) emission. We further explain how we used visibility tapering to promote a common, fiducial beam size and contextualize the interpretation of S/N when detecting molecular emission from protoplanetary disks. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
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    Molecules with ALMA at Planet-forming Scales (MAPS): A Circumplanetary Disk Candidate in Molecular-line Emission in the AS 209 Disk
    (2022) Bae, Jaehan; Teague, Richard; Andrews, Sean M.; Benisty, Myriam; Facchini, Stefano; Galloway-Sprietsma, Maria; Loomis, Ryan A.; Aikawa, Yuri; Alarcon, Felipe; Bergin, Edwin; Bergner, Jennifer B.; Booth, Alice S.; Cataldi, Gianni; Cleeves, L. Ilsedore; Czekala, Ian; Guzman, Viviana V.; Huang, Jane; Ilee, John D.; Kurtovic, Nicolas T.; Law, Charles J.; Le Gal, Romane; Liu, Yao; Long, Feng; Menard, Francois; Oberg, Karin, I; Perez, Laura M.; Qi, Chunhua; Schwarz, Kamber R.; Sierra, Anibal; Walsh, Catherine; Wilner, David J.; Zhang, Ke
    We report the discovery of a circumplanetary disk (CPD) candidate embedded in the circumstellar disk of the T Tauri star AS 209 at a radial distance of about 200 au (on-sky separation of 1.'' 4 from the star at a position angle of 161 degrees), isolated via (CO)-C-13 J = 2-1 emission. This is the first instance of CPD detection via gaseous emission capable of tracing the overall CPD mass. The CPD is spatially unresolved with a 117 x 82 mas beam and manifests as a point source in (CO)-C-13, indicating that its diameter is less than or similar to 14 au. The CPD is embedded within an annular gap in the circumstellar disk previously identified using (CO)-C-12 and near-infrared scattered-light observations and is associated with localized velocity perturbations in (CO)-C-12. The coincidence of these features suggests that they have a common origin: an embedded giant planet. We use the (CO)-C-13 intensity to constrain the CPD gas temperature and mass. We find that the CPD temperature is greater than or similar to 35 K, higher than the circumstellar disk temperature at the radial location of the CPD, 22 K, suggesting that heating sources localized to the CPD must be present. The CPD gas mass is greater than or similar to 0.095 M (Jup) similar or equal to 30 M (circle plus) adopting a standard (CO)-C-13 abundance. From the nondetection of millimeter continuum emission at the location of the CPD (3 sigma flux density less than or similar to 26.4 mu Jy), we infer that the CPD dust mass is less than or similar to 0.027 M (circle plus) similar or equal to 2.2 lunar masses, indicating a low dust-to-gas mass ratio of less than or similar to 9 x 10(-4). We discuss the formation mechanism of the CPD-hosting giant planet on a wide orbit in the framework of gravitational instability and pebble accretion.
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    The Disk Substructures at High Angular Resolution Project (DSHARP). IV. Characterizing Substructures and Interactions in Disks around Multiple Star Systems
    (2018) Kurtovic, Nicolas T.; Perez, Laura M.; Benisty, Myriam; Zhu, Zhaohuan; Zhang, Shangjia; Huang, Jane; Andrews, Sean M.; Dullemond, Cornelis P.; Isella, Andrea; Guzmán Veloso, Viviana Gabriela; Bai, Xue-Ning; Carpenter, John M.; Ricci, Luca; Wilner, David J.
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    The Disk Substructures at High Angular Resolution Project (DSHARP). VI. Dust Trapping in Thin-ringed Protoplanetary Disks
    (2018) Dullemond, Cornelis P.; Birnstiel, Tilman; Huang, Jane; Kurtovic, Nicolas T.; Andrews, Sean M.; Guzmán Veloso, Viviana Gabriela; Pérez, Laura M.; Isella, Andrea; Zhu, Zhaohuan; Benisty, Myriam; Wilner, David J.; Bai, Xue-Ning; Carpenter, John M.; Zhang, Shangjia; Ricci, Luca