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1. The PLATO Mission

Author

Rauer, Heike, Aerts, Conny, Cabrera, Juan, Deleuil, Magali, Erikson, Anders, Gizon, Laurent, Goupil, Mariejo, Heras, Ana, Lorenzo-Alvarez, Jose, Marliani, Filippo, Martin-Garcia, Cesar, Mas-Hesse, J. Miguel, O'Rourke, Laurence, Osborn, Hugh, Pagano, Isabella, Piotto, Giampaolo, Pollacco, Don, Ragazzoni, Roberto, Ramsay, Gavin, Udry, Stéphane, Appourchaux, Thierry, Benz, Willy, Brandeker, Alexis, Güdel, Manuel, Janot-Pacheco, Eduardo, Kabath, Petr, Kjeldsen, Hans, Min, Michiel, Santos, Nuno, Smith, Alan, Suarez, Juan-Carlos, Werner, Stephanie C., Aboudan, Alessio, Abreu, Manuel, Acuña, Lorena, Adams, Moritz, Adibekyan, Vardan, Affer, Laura, Agneray, François, Agnor, Craig, Børsen-Koch, Victor Aguirre, Ahmed, Saad, Aigrain, Suzanne, Al-Bahlawan, Ashraf, Gil, M de los Angeles Alcacera, Alei, Eleonora, Alencar, Silvia, Alexander, Richard, Alfonso-Garzón, Julia, Alibert, Yann, Prieto, Carlos Allende, Almeida, Leonardo, Sobrino, Roi Alonso, Altavilla, Giuseppe, Althaus, Christian, Trujillo, Luis Alonso Alvarez, Amarsi, Anish, Eiff, Matthias Ammler-von, Amôres, Eduardo, Andrade, Laerte, Antoniadis-Karnavas, Alexandros, António, Carlos, del Moral, Beatriz Aparicio, Appolloni, Matteo, Arena, Claudio, Armstrong, David, Aliaga, Jose Aroca, Asplund, Martin, Audenaert, Jeroen, Auricchio, Natalia, Avelino, Pedro, Baeke, Ann, Baillié, Kevin, Balado, Ana, Balestra, Andrea, Ball, Warrick, Ballans, Herve, Ballot, Jerome, Barban, Caroline, Barbary, Gaële, Barbieri, Mauro, Forteza, Sebastià Barceló, Barker, Adrian, Barklem, Paul, Barnes, Sydney, Navascues, David Barrado, Barragan, Oscar, Baruteau, Clément, Basu, Sarbani, Baudin, Frederic, Baumeister, Philipp, Bayliss, Daniel, Bazot, Michael, Beck, Paul G., Bedding, Tim, Belkacem, Kevin, Bellinger, Earl, Benatti, Serena, Benomar, Othman, Bérard, Diane, Bergemann, Maria, Bergomi, Maria, Bernardo, Pierre, Biazzo, Katia, Bignamini, Andrea, Bigot, Lionel, Billot, Nicolas, Binet, Martin, Biondi, David, Biondi, Federico, Birch, Aaron C., Bitsch, Bertram, Ceballos, Paz Victoria Bluhm, Bódi, Attila, Bognár, Zsófia, Boisse, Isabelle, Bolmont, Emeline, Bonanno, Alfio, Bonavita, Mariangela, Bonfanti, Andrea, Bonfils, Xavier, Bonito, Rosaria, Bonomo, Aldo Stefano, Börner, Anko, Saikia, Sudeshna Boro, Martín, Elisa Borreguero, Borsa, Francesco, Borsato, Luca, Bossini, Diego, Bouchy, Francois, Boué, Gwenaël, Boufleur, Rodrigo, Boumier, Patrick, Bourrier, Vincent, Bowman, Dominic M., Bozzo, Enrico, Bradley, Louisa, Bray, John, Bressan, Alessandro, Breton, Sylvain, Brienza, Daniele, Brito, Ana, Brogi, Matteo, Brown, Beverly, Brown, David, Brun, Allan Sacha, Bruno, Giovanni, Bruns, Michael, Buchhave, Lars A., Bugnet, Lisa, Buldgen, Gaël, Burgess, Patrick, Busatta, Andrea, Busso, Giorgia, Buzasi, Derek, Caballero, José A., Cabral, Alexandre, Calderone, Flavia, Cameron, Robert, Cameron, Andrew, Campante, Tiago, Martins, Bruno Leonardo Canto, Cara, Christophe, Carone, Ludmila, Carrasco, Josep Manel, Casagrande, Luca, Casewell, Sarah L., Cassisi, Santi, Castellani, Marco, Castro, Matthieu, Catala, Claude, Fernández, Irene Catalán, Catelan, Márcio, Cegla, Heather, Cerruti, Chiara, Cessa, Virginie, Chadid, Merieme, Chaplin, William, Charpinet, Stephane, Chiappini, Cristina, Chiarucci, Simone, Chiavassa, Andrea, Chinellato, Simonetta, Chirulli, Giovanni, Christensen-Dalsgaard, Jorgen, Church, Ross, Claret, Antonio, Clarke, Cathie, Claudi, Riccardo, Clermont, Lionel, Coelho, Hugo, Coelho, Joao, Cogato, Fabrizio, Colomé, Josep, Condamin, Mathieu, Conseil, Simon, Corbard, Thierry, Correia, Alexandre C. M., Corsaro, Enrico, Cosentino, Rosario, Costes, Jean, Cottinelli, Andrea, Covone, Giovanni, Creevey, Orlagh L., Crida, Aurelien, Csizmadia, Szilard, Cunha, Margarida, Curry, Patrick, da Costa, Jefferson, da Silva, Francys, Dalal, Shweta, Damasso, Mario, Damiani, Cilia, Damiani, Francesco, Chagas, Maria Liduina das, Davies, Melvyn, Davies, Guy, Davies, Ben, Davison, Gary, de Almeida, Leandro, de Angeli, Francesca, de Barros, Susana Cristina Cabral, Leão, Izan de Castro, de Freitas, Daniel Brito, de Freitas, Marcia Cristina, De Martino, Domitilla, de Medeiros, José Renan, de Paula, Luiz Alberto, de Plaa, Jelle, De Ridder, Joris, Deal, Morgan, Decin, Leen, Deeg, Hans, Degl'Innocenti, Scilla, Deheuvels, Sebastien, del Burgo, Carlos, Del Sordo, Fabio, Delgado-Mena, Elisa, Demangeon, Olivier, Denk, Tilmann, Derekas, Aliz, Desidera, Silvano, Dexet, Marc, Di Criscienzo, Marcella, Di Giorgio, Anna Maria, Di Mauro, Maria Pia, Rial, Federico Jose Diaz, Díaz-García, José-Javier, Dima, Marco, Dinuzzi, Giacomo, Dionatos, Odysseas, Distefano, Elisa, Nascimento Jr., Jose-Dias do, Domingo, Albert, D'Orazi, Valentina, Dorn, Caroline, Doyle, Lauren, Duarte, Elena, Ducellier, Florent, Dumaye, Luc, Dumusque, Xavier, Dupret, Marc-Antoine, Eggenberger, Patrick, Ehrenreich, David, Eigmüller, Philipp, Eising, Johannes, Emilio, Marcelo, Eriksson, Kjell, Ermocida, Marco, Giribaldi, Riano Isidoro Escate, Eschen, Yoshi, Estrela, Inês, Evans, Dafydd Wyn, Fabbian, Damian, Fabrizio, Michele, Faria, João Pedro, Farina, Maria, Farinato, Jacopo, Feliz, Dax, Feltzing, Sofia, Fenouillet, Thomas, Ferrari, Lorenza, Ferraz-Mello, Sylvio, Fialho, Fabio, Fienga, Agnes, Figueira, Pedro, Fiori, Laura, Flaccomio, Ettore, Focardi, Mauro, Foley, Steve, Fontignie, Jean, Ford, Dominic, Fornazier, Karin, Forveille, Thierry, Fossati, Luca, Franca, Rodrigo de Marca, da Silva, Lucas Franco, Frasca, Antonio, Fridlund, Malcolm, Furlan, Marco, Gabler, Sarah-Maria, Gaido, Marco, Gallagher, Andrew, Galli, Emanuele, Garcia, Rafael A., Hernández, Antonio García, Munoz, Antonio Garcia, García-Vázquez, Hugo, Haba, Rafael Garrido, Gaulme, Patrick, Gauthier, Nicolas, Gehan, Charlotte, Gent, Matthew, Georgieva, Iskra, Ghigo, Mauro, Giana, Edoardo, Gill, Samuel, Girardi, Leo, Winter, Silvia Giuliatti, Giusi, Giovanni, da Silva, João Gomes, Zazo, Luis Jorge Gómez, Gomez-Lopez, Juan Manuel, Hernández, Jonay Isai González, Murillo, Kevin Gonzalez, Gorius, Nicolas, Gouel, Pierre-Vincent, Goulty, Duncan, Granata, Valentina, Grenfell, John Lee, Grießbach, Denis, Grolleau, Emmanuel, Grouffal, Salomé, Grziwa, Sascha, Guarcello, Mario Giuseppe, Gueguen, Loïc, Guenther, Eike Wolf, Guilhem, Terrasa, Guillerot, Lucas, Guiot, Pierre, Guterman, Pascal, Gutiérrez, Antonio, Gutiérrez-Canales, Fernando, Hagelberg, Janis, Haldemann, Jonas, Hall, Cassandra, Handberg, Rasmus, Harrison, Ian, Harrison, Diana L., Hasiba, Johann, Haswell, Carole A., Hatalova, Petra, Hatzes, Artie, Haywood, Raphaelle, Hébrard, Guillaume, Heckes, Frank, Heiter, Ulrike, Hekker, Saskia, Heller, René, Helling, Christiane, Helminiak, Krzysztof, Hemsley, Simon, Heng, Kevin, Hermans, Aline, Hermes, JJ, Torres, Nadia Hidalgo, Hinkel, Natalie, Hobbs, David, Hodgkin, Simon, Hofmann, Karl, Hojjatpanah, Saeed, Houdek, Günter, Huber, Daniel, Huesler, Joseph, Hui-Bon-Hoa, Alain, Huygen, Rik, Huynh, Duc-Dat, Iro, Nicolas, Irwin, Jonathan, Irwin, Mike, Izidoro, André, Jacquinod, Sophie, Jannsen, Nicholas Emborg, Janson, Markus, Jeszenszky, Harald, Jiang, Chen, Mancebo, Antonio José Jimenez, Jofre, Paula, Johansen, Anders, Johnston, Cole, Jones, Geraint, Kallinger, Thomas, Kálmán, Szilárd, Kanitz, Thomas, Karjalainen, Marie, Karjalainen, Raine, Karoff, Christoffer, Kawaler, Steven, Kawata, Daisuke, Keereman, Arnoud, Keiderling, David, Kennedy, Tom, Kenworthy, Matthew, Kerschbaum, Franz, Kidger, Mark, Kiefer, Flavien, Kintziger, Christian, Kislyakova, Kristina, Kiss, László, Klagyivik, Peter, Klahr, Hubert, Klevas, Jonas, Kochukhov, Oleg, Köhler, Ulrich, Kolb, Ulrich, Koncz, Alexander, Korth, Judith, Kostogryz, Nadiia, Kovács, Gábor, Kovács, József, Kozhura, Oleg, Krivova, Natalie, Kučinskas, Arunas, Kuhlemann, Ilyas, Kupka, Friedrich, Laauwen, Wouter, Labiano, Alvaro, Lagarde, Nadege, Laget, Philippe, Laky, Gunter, Lam, Kristine Wai Fun, Lambrechts, Michiel, Lammer, Helmut, Lanza, Antonino Francesco, Lanzafame, Alessandro, Martiz, Mariel Lares, Laskar, Jacques, Latter, Henrik, Lavanant, Tony, Lawrenson, Alastair, Lazzoni, Cecilia, Lebre, Agnes, Lebreton, Yveline, Etangs, Alain Lecavelier des, Leinhardt, Zoe, Leleu, Adrien, Lendl, Monika, Leto, Giuseppe, Levillain, Yves, Libert, Anne-Sophie, Lichtenberg, Tim, Ligi, Roxanne, Lignieres, Francois, Lillo-Box, Jorge, Linsky, Jeffrey, Liu, John Scige, Loidolt, Dominik, Longval, Yuying, Lopes, Ilídio, Lorenzani, Andrea, Ludwig, Hans-Guenter, Lund, Mikkel, Lundkvist, Mia Sloth, Luri, Xavier, Maceroni, Carla, Madden, Sean, Madhusudhan, Nikku, Maggio, Antonio, Magliano, Christian, Magrin, Demetrio, Mahy, Laurent, Maibaum, Olaf, Malac-Allain, LeeRoy, Malapert, Jean-Christophe, Malavolta, Luca, Maldonado, Jesus, Mamonova, Elena, Manchon, Louis, Mann, Andrew, Mantovan, Giacomo, Marafatto, Luca, Marconi, Marcella, Mardling, Rosemary, Marigo, Paola, Marinoni, Silvia, Marques, Érico, Marques, Joao Pedro, Marrese, Paola Maria, Marshall, Douglas, Perales, Silvia Martínez, Mary, David, Marzari, Francesco, Masana, Eduard, Mascher, Andrina, Mathis, Stéphane, Mathur, Savita, Figueiredo, Ana Carolina Mattiuci, Maxted, Pierre F. L., Mazeh, Tsevi, Mazevet, Stephane, Mazzei, Francesco, McCormac, James, McMillan, Paul, Menou, Lucas, Merle, Thibault, Meru, Farzana, Mesa, Dino, Messina, Sergio, Mészáros, Szabolcs, Meunier, Nadége, Meunier, Jean-Charles, Micela, Giuseppina, Michaelis, Harald, Michel, Eric, Michielsen, Mathias, Michtchenko, Tatiana, Miglio, Andrea, Miguel, Yamila, Milligan, David, Mirouh, Giovanni, Mitchell, Morgan, Moedas, Nuno, Molendini, Francesca, Molnár, László, Mombarg, Joey, Montalban, Josefina, Montalto, Marco, Monteiro, Mário J. P. F. G., Morales, Juan Carlos, Morales-Calderon, Maria, Morbidelli, Alessandro, Mordasini, Christoph, Moreau, Chrystel, Morel, Thierry, Morello, Guiseppe, Morin, Julien, Mortier, Annelies, Mosser, Benoît, Mourard, Denis, Mousis, Olivier, Moutou, Claire, Mowlavi, Nami, Moya, Andrés, Muehlmann, Prisca, Muirhead, Philip, Munari, Matteo, Musella, Ilaria, Mustill, Alexander James, Nardetto, Nicolas, Nardiello, Domenico, Narita, Norio, Nascimbeni, Valerio, Nash, Anna, Neiner, Coralie, Nelson, Richard P., Nettelmann, Nadine, Nicolini, Gianalfredo, Nielsen, Martin, Niemi, Sami-Matias, Noack, Lena, Noels-Grotsch, Arlette, Noll, Anthony, Norazman, Azib, Norton, Andrew J., Nsamba, Benard, Ofir, Aviv, Ogilvie, Gordon, Olander, Terese, Olivetto, Christian, Olofsson, Göran, Ong, Joel, Ortolani, Sergio, Oshagh, Mahmoudreza, Ottacher, Harald, Ottensamer, Roland, Ouazzani, Rhita-Maria, Paardekooper, Sijme-Jan, Pace, Emanuele, Pajas, Miriam, Palacios, Ana, Palandri, Gaelle, Palle, Enric, Paproth, Carsten, Parro, Vanderlei, Parviainen, Hannu, Granado, Javier Pascual, Passegger, Vera Maria, Pastor-Morales, Carmen, Pätzold, Martin, Pedersen, May Gade, Hidalgo, David Pena, Pepe, Francesco, Pereira, Filipe, Persson, Carina M., Pertenais, Martin, Peter, Gisbert, Petit, Antoine C., Petit, Pascal, Pezzuto, Stefano, Pichierri, Gabriele, Pietrinferni, Adriano, Pinheiro, Fernando, Pinsonneault, Marc, Plachy, Emese, Plasson, Philippe, Plez, Bertrand, Poppenhaeger, Katja, Poretti, Ennio, Portaluri, Elisa, Portell, Jordi, de Mello, Gustavo Frederico Porto, Poyatos, Julien, Pozuelos, Francisco J., Moroni, Pier Giorgio Prada, Pricopi, Dumitru, Prisinzano, Loredana, Quade, Matthias, Quirrenbach160, ndreas, Reina6, Julio Arturo Rabanal, Soares, Maria Cristina Rabello, Raimondo, Gabriella, Rainer, Monica, Rodón, Jose Ramón, Ramón-Ballesta, Alejandro, Zapata, Gonzalo Ramos, Rätz, Stefanie, Rauterberg, Christoph, Redman, Bob, Redmer, Ronald, Reese, Daniel, Regibo, Sara, Reiners, Ansgar, Reinhold, Timo, Renie, Christian, Ribas, Ignasi, Ribeiro, Sergio, Ricciardi, Thiago Pereira, Rice, Ken, Richard, Olivier, Riello, Marco, Rieutord, Michel, Ripepi, Vincenzo, Rixon, Guy, Rockstein, Steve, Rodríguez, María Teresa Rodrigo, Díaz, Luisa Fernanda Rodríguez, Garcia, Juan Pablo Rodriguez, Rodriguez-Gomez, Julio, Roehlly, Yannick, Roig, Fernando, Rojas-Ayala, Bárbara, Rolf, Tobias, Rørsted, Jakob Lysgaard, Rosado, Hugo, Rosotti, Giovanni, Roth, Olivier, Roth, Markus, Rousseau, Alex, Roxburgh, Ian, Roy, Fabrice, Royer, Pierre, Ruane, Kirk, Mastropasqua, Sergio Rufini, de Galarreta, Claudia Ruiz, Russi, Andrea, Saar, Steven, Saillenfest, Melaine, Salaris, Maurizio, Salmon, Sebastien, Saltas, Ippocratis, Samadi, Réza, Samadi, Aunia, Samra, Dominic, da Silva, Tiago Sanches, Carrasco, Miguel Andrés Sánchez, Santerne, Alexandre, Santoli, Francesco, Santos, Ângela R. G., Mesa, Rosario Sanz, Sarro, Luis Manuel, Scandariato, Gaetano, Schäfer, Martin, Schlafly, Edward, Schmider, François-Xavier, Schneider, Jean, Schou, Jesper, Schunker, Hannah, Schwarzkopf, Gabriel Jörg, Serenelli, Aldo, Seynaeve, Dries, Shan, Yutong, Shapiro, Alexander, Shipman, Russel, Sicilia, Daniela, Sanmartin, Maria Angeles Sierra, Sigot, Axelle, Silliman, Kyle, Silvotti, Roberto, Simon, Attila E., Napoli, Ricardo Simoyama, Skarka, Marek, Smalley, Barry, Smiljanic, Rodolfo, Smit, Samuel, Smith, Alexis, Smith, Leigh, Snellen, Ignas, Sódor, Ádám, Sohl, Frank, Solanki, Sami K., Sortino, Francesca, Sousa, Sérgio, Southworth, John, Souto, Diogo, Sozzetti, Alessandro, Stamatellos, Dimitris, Stassun, Keivan, Steller, Manfred, Stello, Dennis, Stelzer, Beate, Stiebeler, Ulrike, Stokholm, Amalie, Storelvmo, Trude, Strassmeier, Klaus, Strøm, Paul Anthony, Strugarek, Antoine, Sulis, Sophia, Švanda, Michal, Szabados, László, Szabó, Róbert, Szabó, Gyula M., Szuszkiewicz, Ewa, Talens, Geert Jan, Teti, Daniele, Theisen, Tom, Thévenin, Frédéric, Thoul, Anne, Tiphene, Didier, Titz-Weider, Ruth, Tkachenko, Andrew, Tomecki, Daniel, Tonfat, Jorge, Tosi, Nicola, Trampedach, Regner, Traven, Gregor, Triaud, Amaury, Trønnes, Reidar, Tsantaki, Maria, Tschentscher, Matthias, Turin, Arnaud, Tvaruzka, Adam, Ulmer, Bernd, Ulmer-Moll, Solène, Ulusoy, Ceren, Umbriaco, Gabriele, Valencia, Diana, Valentini, Marica, Valio, Adriana, Guijarro, Ángel Luis Valverde, Van Eylen, Vincent, Van Grootel, Valerie, van Kempen, Tim A., Van Reeth, Timothy, Van Zelst, Iris, Vandenbussche, Bart, Vasiliou, Konstantinos, Vasilyev, Valeriy, de Mascarenhas, David Vaz, Vazan, Allona, Nunez, Marina Vela, Velloso, Eduardo Nunes, Ventura, Rita, Ventura, Paolo, Venturini, Julia, Trallero, Isabel Vera, Veras, Dimitri, Verdugo, Eva, Verma, Kuldeep, Vibert, Didier, Martinez, Tobias Vicanek, Vida, Krisztián, Vigan, Arthur, Villacorta, Antonio, Villaver, Eva, Aparicio, Marcos Villaverde, Viotto, Valentina, Vorobyov, Eduard, Vorontsov, Sergey, Wagner, Frank W., Walloschek, Thomas, Walton, Nicholas, Walton, Dave, Wang, Haiyang, Waters, Rens, Watson, Christopher, Wedemeyer, Sven, Weeks, Angharad, Weingril, Jörg, Weiss, Annita, Wendler, Belinda, West, Richard, Westerdorff, Karsten, Westphal, Pierre-Amaury, Wheatley, Peter, White, Tim, Whittaker, Amadou, Wickhusen, Kai, Wilson, Thomas, Windsor, James, Winter, Othon, Winther, Mark Lykke, Winton, Alistair, Witteck, Ulrike, Witzke, Veronika, Woitke, Peter, Wolter, David, Wuchterl, Günther, Wyatt, Mark, Yang, Dan, Yu, Jie, Sanchez, Ricardo Zanmar, Osorio, María Rosa Zapatero, Zechmeister, Mathias, Zhou, Yixiao, Ziemke, Claas, and Zwintz, Konstanze

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

PLATO (PLAnetary Transits and Oscillations of stars) is ESA's M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large number of stars. PLATO will detect small planets (down to <2 R_(Earth)) around bright stars (<11 mag), including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observations from the ground, planets will be characterised for their radius, mass, and age with high accuracy (5 %, 10 %, 10 % for an Earth-Sun combination respectively). PLATO will provide us with a large-scale catalogue of well-characterised small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our Solar System planets in a broader context. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements. Here we review the science objectives, present PLATO's target samples and fields, provide an overview of expected core science performance as well as a description of the instrument and the mission profile at the beginning of the serial production of the flight cameras. PLATO is scheduled for a launch date end 2026. This overview therefore provides a summary of the mission to the community in preparation of the upcoming operational phases.

Published
2024

2. Mode Mixing and Rotational Splittings: II. Reconciling Different Approaches to Mode Coupling

Author

Ong, J. M. Joel and Gehan, Charlotte

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

In the mixed-mode asteroseismology of subgiants and red giants, the coupling between the p- and g-mode cavities must be understood well in order to derive localised estimates of interior rotation from measurements of mode multiplet rotational splittings. There exist now two different descriptions of this coupling: one based on an asymptotic quantisation condition, and the other arising from coupling matrices associated with "acoustic molecular orbitals". We examine the analytic properties of both, and derive closed-form expressions for various quantities -- such as the period-stretching function $\tau$ -- which previously had to be solved for numerically. Using these, we reconcile both formulations for the first time, deriving relations by which quantities in each formulation may be translated to and interpreted within the other. This yields an information criterion for whether a given configuration of mixed modes meaningfully constrains the parameters of the asymptotic construction, which is likely not satisfied by the majority of first-ascent red giant stars in our observational sample. Since this construction has been already used to make rotational measurements of such red giants, we examine -- through a hare-and-hounds exercise -- whether, and how, such limitations affect existing measurements. While averaged estimates of core rotation seem fairly robust, template-matching using the asymptotic construction has difficulty reliably assigning rotational splittings to individual multiplets, or estimating mixing fractions $\zeta$ of the most p-dominated mixed modes, where such estimates are most needed. We finally discuss implications for extending the two-zone model of radial differential rotation, e.g. via rotational inversions, with these methods., Comment: 23 pages, 13 figures. Accepted for publication in ApJ

Published
2023
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3. TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting An Extremely Eccentric Exoplanet

Author

Jiang, Chen, Wu, Tao, Feinstein, Adina D., Stassun, Keivan G., Bedding, Timothy R., Veras, Dimitri, Corsaro, Enrico, Buzasi, Derek L., Stello, Dennis, Li, Yaguang, Mathur, Savita, Garcia, Rafael A., Breton, Sylvain N., Lundkvist, Mia S., Mikolajczyk, Przemyslaw J., Gehan, Charlotte, Campante, Tiago L., Bossini, Diego, Kane, Stephen R., Ong, Jia Mian Joel, Yildiz, Mutlu, Kayhan, Cenk, Orhan, Zeynep Celik, Ortel, Sibel, Zhang, Xinyi, Cunha, Margarida S., de Moura, Bruno Lustosa, Yu, Jie, Huber, Daniel, Ou, Jian-wen, Wittenmyer, Robert A., Gizon, Laurent, and Chaplin, William J.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Transiting Exoplanet Survey Satellite (TESS) mission searches for new exoplanets. The observing strategy of TESS results in high-precision photometry of millions of stars across the sky, allowing for detailed asteroseismic studies of individual systems. In this work, we present a detailed asteroseismic analysis of the giant star HD 76920 hosting a highly eccentric giant planet ($e = 0.878$) with an orbital period of 415 days, using 5 sectors of TESS light curve that cover around 140 days of data. Solar-like oscillations in HD 76920 are detected around $52 \, \mu$Hz by TESS for the first time. By utilizing asteroseismic modeling that takes classical observational parameters and stellar oscillation frequencies as constraints, we determine improved measurements of the stellar mass ($1.22 \pm 0.11\, M_\odot$), radius ($8.68 \pm 0.34\,R_\odot$), and age ($5.2 \pm 1.4\,$Gyr). With the updated parameters of the host star, we update the semi-major axis and mass of the planet as $a=1.165 \pm 0.035$ au and $M_{\rm p}\sin{i} = 3.57 \pm 0.22\,M_{\rm Jup}$. With an orbital pericenter of $0.142 \pm 0.005$ au, we confirm that the planet is currently far away enough from the star to experience negligible tidal decay until being engulfed in the stellar envelope. We also confirm that this event will occur within about 100\,Myr, depending on the stellar model used., Comment: 18 pages, 7 figures, 4 tables

Published
2023
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4. Surface magnetism of rapidly rotating red giants: single versus close binary stars

Author

Gehan, Charlotte, Gaulme, Patrick, and Yu, Jie

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

According to dynamo theory, stars with convective envelopes efficiently generate surface magnetic fields, which manifest as magnetic activity in the form of starspots, faculae, flares, when their rotation period is shorter than their convective turnover time. Most red giants, having undergone significant spin down while expanding, have slow rotation and no spots. However, based on a sample of about 4500 red giants observed by the NASA Kepler mission, a previous study showed that about 8 % display spots, including about 15 % that belong to close binary systems. Here, we shed light on a puzzling fact: for rotation periods less than 80 days, a red giant that belongs to a close binary system displays a photometric modulation about an order of magnitude larger than that of a single red giant with similar rotational period and physical properties. We investigate whether binarity leads to larger magnetic fields when tides lock systems, or if a different spot distribution on single versus close binary stars can explain this fact. For this, we measure the chromospheric emission in the CaII H & K lines of 3130 of the 4465 stars studied in a previous work thanks to the LAMOST survey. We show that red giants in a close-binary configuration with spin-orbit resonance display significantly larger chromospheric emission than single stars, suggesting that tidal locking leads to larger magnetic fields at a fixed rotational period. Beyond bringing interesting new observables to study the evolution of binary systems, this result could be used to distinguish single versus binary red giants in automatic pipelines based on machine learning., Comment: 10 pages, 8 Figures, accepted for publication in A&A

Published
2022
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5. Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?

Author

Tayar, Jamie, Moyano, Facundo D., Soares-Furtado, Melinda, Escorza, Ana, Joyce, Meridith, Martell, Sarah L., García, Rafael A., Breton, Sylvain N., Mathis, Stéphane, Mathur, Savita, Delsanti, Vincent, Kiefer, Sven, Reffert, Sabine, Bowman, Dominic M., Van Reeth, Timothy, Shetye, Shreeya, Gehan, Charlotte, and Grunblatt, Samuel K.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

In this paper, we report the potential detection of a nonmonotonic radial rotation profile in a low-mass lower-luminosity giant star. For most low- and intermediate-mass stars, the rotation on the main sequence seems to be close to rigid. As these stars evolve into giants, the core contracts and the envelope expands, which should suggest a radial rotation profile with a fast core and a slower envelope and surface. KIC 9267654, however, seems to show a surface rotation rate that is faster than its bulk envelope rotation rate, in conflict with this simple angular momentum conservation argument. We improve the spectroscopic surface constraint, show that the pulsation frequencies are consistent with the previously published core and envelope rotation rates, and demonstrate that the star does not show strong chemical peculiarities. We discuss the evidence against any tidally interacting stellar companion. Finally, we discuss the possible origin of this unusual rotation profile, including the potential ingestion of a giant planet or unusual angular momentum transport by tidal inertial waves triggered by a close substellar companion, and encourage further observational and theoretical efforts., Comment: 18 pages, 9 figures, submitted to AAS Journals

Published
2022
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6. A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c

Author

Huber, Daniel, White, Timothy R., Metcalfe, Travis S., Chontos, Ashley, Fausnaugh, Michael M., Ho, Cynthia S. K., Van Eylen, Vincent, Ball, Warrick, Basu, Sarbani, Bedding, Timothy R., Benomar, Othman, Bossini, Diego, Breton, Sylvain, Buzasi, Derek L., Campante, Tiago L., Chaplin, William J., Christensen-Dalsgaard, Joergen, Cunha, Margarida S., Deal, Morgan, Garcia, Rafael A., Munoz, Antonio Garcia, Gehan, Charlotte, Gonzalez-Cuesta, Lucia, Jiang, Chen, Kayhan, Cenk, Kjeldsen, Hans, Lundkvist, Mia S., Mathis, Stephane, Mathur, Savita, Monteiro, Mario J. P. F. G., Nsamba, Benard, Ong, Jia Mian Joel, Pakstiene, Erika, Serenelli, Aldo M., Aguirre, Victor Silva, Stassun, Keivan G., Stello, Dennis, Stilling, Sissel Norgaard, Winther, Mark Lykke, Wu, Tao, Barclay, Thomas, Daylan, Tansu, Guenther, Maximilian N., Hermes, J. J., Jenkins, Jon M., Latham, David W., Levine, Alan M., Ricker, George R., Seager, Sara, Shporer, Avi, Twicken, Joseph D., Vanderspek, Roland K., and Winn, Joshua N.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present an analysis of the first 20-second cadence light curves obtained by the TESS space telescope during its extended mission. We find a precision improvement of 20-second data compared to 2-minute data for bright stars when binned to the same cadence (~10-25% better for T<~8 mag, reaching equal precision at T~13 mag), consistent with pre-flight expectations based on differences in cosmic ray mitigation algorithms. We present two results enabled by this improvement. First, we use 20-second data to detect oscillations in three solar analogs (gamma Pav, zeta Tuc and pi Men) and use asteroseismology to measure their radii, masses, densities and ages to ~1%, ~3%, ~1% and ~20% respectively, including systematic errors. Combining our asteroseismic ages with chromospheric activity measurements we find evidence that the spread in the activity-age relation is linked to stellar mass and thus convection-zone depth. Second, we combine 20-second data and published radial velocities to re-characterize pi Men c, which is now the closest transiting exoplanet for which detailed asteroseismology of the host star is possible. We show that pi Men c is located at the upper edge of the planet radius valley for its orbital period, confirming that it has likely retained a volatile atmosphere and that the "asteroseismic radius valley" remains devoid of planets. Our analysis favors a low eccentricity for pi Men c (<0.1 at 68% confidence), suggesting efficient tidal dissipation (Q/k <~ 2400) if it formed via high-eccentricity migration. Combined, these early results demonstrate the strong potential of TESS 20-second cadence data for stellar astrophysics and exoplanet science., Comment: 17 pages (excluding references), 13 figures, 6 tables; accepted for publication in AJ. Data and scripts to reproduce results are archived at https://zenodo.org/record/5555456

Published
2021
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7. Large-scale measurements of the red giant core rotation through asteroseismology

Author

Gehan, Charlotte, Mosser, Benoît, and Michel, Eric

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Red giant stars are solar-like pulsators presenting mixed-modes. Such modes consist in a coupling between pressure waves propagating in the external convective envelope and gravity waves propagating in the radiative interior. Therefore, the red giant asteroseismology provides us with a direct view on their core and opens the possibility to monitor the evolution of their core rotation. Previous measurements of the mean core rotation revealed that angular momentum is efficiently transferred from the core to the envelope inside red giants, but the physical mechanisms at work are not yet fully understood. We thus need stronger observational constraints on the evolution of the red giant core rotation. In this context, we developed an automated method to determine the mean core rotation of red giant branch stars observed with Kepler. This automated method is paving the way for the future PLATO data, representing hundreds of thousands of potential red giant oscillation spectra. Results obtained for almost 1200 red giant branch stars indicate that the rate of the core rotation braking is lower than previously estimated and does not seem to depend on the stellar mass., Comment: 5 pages, 3 figures, 2 tables, SF2A 2017

Published
2017

8. Measuring the core rotation of red giant stars

Author

Gehan, Charlotte, Mosser, Benoît, and Michel, Eric

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Red giant stars present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative interior. This mixed character allows to probe the physical conditions in their core. With the advent of long-duration time series from space-borne missions such as CoRoT and Kepler, it becomes possible to study the red giant core rotation. As more than 15 000 red giant light curves have been recorded, it is crucial to develop a robust and efficient method to measure this rotation. Such measurements of thousands of mean core rotation would open the way to a deeper understanding of the physical mechanisms that are able to transport angular momentum from the core to the envelope in red giants. In this work, we detail the principle of the method we developed to obtain automatic measurements of the red giant mean core rotation. This method is based on the stretching of the oscillation spectra and on the use of the so-called Hough transform. We finally validate this method for stars on the red giant branch, where overlapping rotational splittings and mixed-mode spacings produce complicated frequency spectra., Comment: 8 pages, 3 figures, 1 table

Published
2016
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9. Rapidly rotating red giants

Author

Gehan, Charlotte, Mosser, Benoît, and Michel, Eric

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the identification of mode crossings is precise and efficient. The determination of the mean core rotation directly derives from the precise measurement of the asymptotic period spacing {\Delta}{\Pi}1 and of the frequency at which the crossing of the rotational components is observed., Comment: 4 pages, 2 figures, 2 tables, to be published in the Astro Fluid 2016 Conference Proceedings, editor EAS Publications Series

Published
2016
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10. Magnetic activity of red giants: impact of tidal interactions on magnetic fields

Author

Gehan, Charlotte and Gaulme, Patrick

Abstract

According to dynamo theory, stars with convective envelopes efficiently generate surface magnetic fields, which manifest as magnetic activity in the form of starspots, faculae, flares, when their rotation period is shorter than their convective turnover time. Most red giants, having undergone significant spin down while expanding, have slow rotation, thus no spots. However, some red giants that belong to close binary systems display a photospheric activity measured from photometric time series produced by the NASA Kepler mission, which is about an order of magnitude larger than that of single red giants with similar rotation periods. In order to investigate whether binarity leads to larger magnetic fields when tides lock systems, or if a different spot distribution on single versus close binary red giants can explain this fact, we measured the chromospheric emission in the CaII H & K lines of LAMOST optical spectra. We find that red giants belonging to binary systems in a configuration of spin-orbit resonance display significantly larger chromospheric emission than single stars, suggesting that tidal interactions lead to larger magnetic fields. In other words, the large magnetic field of red giants in close binary systems is not only due to the faster rotation rate induced by tidal interactions. Somehow, our work resuscitates an old speculation about a special binary-induced dynamo activity.

Published
2023
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13. TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting an Extremely Eccentric Exoplanet

Author

Jiang, Chen, primary, Wu, Tao, additional, Feinstein, Adina D., additional, Stassun, Keivan G., additional, Bedding, Timothy R., additional, Veras, Dimitri, additional, Corsaro, Enrico, additional, Buzasi, Derek L., additional, Stello, Dennis, additional, Li, Yaguang, additional, Mathur, Savita, additional, García, Rafael A., additional, Breton, Sylvain N., additional, Lundkvist, Mia S., additional, Mikołajczyk, Przemysław J., additional, Gehan, Charlotte, additional, Campante, Tiago L., additional, Bossini, Diego, additional, Kane, Stephen R., additional, Joel Ong, Jia Mian, additional, Yıldız, Mutlu, additional, Kayhan, Cenk, additional, Çelik Orhan, Zeynep, additional, Örtel, Sibel, additional, Zhang, Xinyi, additional, Cunha, Margarida S., additional, de Moura, Bruno Lustosa, additional, Yu, Jie, additional, Huber, Daniel, additional, Ou, Jian-wen, additional, Wittenmyer, Robert A., additional, Gizon, Laurent, additional, and Chaplin, William J., additional

Published
2023
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15. KIC 7955301: A hierarchical triple system with eclipse timing variations and an oscillating red giant

Author

Gaulme, Patrick, primary, Borkovits, Tamás, additional, Appourchaux, Thierry, additional, Pavlovski, Krešimir, additional, Spada, Federico, additional, Gehan, Charlotte, additional, Ong, Joel, additional, Miglio, Andrea, additional, Tkachenko, Andrew, additional, Mosser, Benoît, additional, Vrard, Mathieu, additional, Benbakoura, Mansour, additional, Drew Chojnowski, Stephen, additional, Perkins, Jean, additional, Hedlund, Anne, additional, and Jackiewicz, Jason, additional

Published
2022
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16. Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?

Author

Tayar, Jamie, primary, Moyano, Facundo D., additional, Soares-Furtado, Melinda, additional, Escorza, Ana, additional, Joyce, Meridith, additional, Martell, Sarah L., additional, García, Rafael A., additional, Breton, Sylvain N., additional, Mathis, Stéphane, additional, Mathur, Savita, additional, Delsanti, Vincent, additional, Kiefer, Sven, additional, Reffert, Sabine, additional, Bowman, Dominic M., additional, Van Reeth, Timothy, additional, Shetye, Shreeya, additional, Gehan, Charlotte, additional, and Grunblatt, Samuel K., additional

Published
2022
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17. FRA – A new Fast, Robust and Automated pipeline for the detection of solar-like oscillations among red giants

Author

Gehan, Charlotte, Campante, Tiago, Cunha, Margarida, and Pereira, Filipe

Subjects
Astrophysics::Earth and Planetary Astrophysics
Abstract

Being able to assess the presence of solar-like oscillations in stellar power spectra is a pre-requisite to any seismic analysis. Given the increasing harvest of ligthcurves obtained by the space missions Kepler, TESS, and in the coming years, PLATO, it is crucial to have a fast, robust and automated tool at hand. We developed a new pipeline allowing the Fast, Robust and Automated (FRA) detection of solar-like oscillations. It is based on the detection and measurement of the frequency of maximum oscillation power, νmax, and runs in a few seconds of CPU time. Our pipeline allows to measure νmax independently from the large separation, ∆ν, while using statistical criteria to validate or not the obtained measurement, and thus confirm or not the presence of oscillations. I present here the results we obtain when applying the FRA pipeline to ∼ 1700 Kepler and ∼ 2300 TESS red giants, as well as ∼ 250 artificial power spectra representative of TESS red giants. The analysis of artificial power spectra provides limits in magnitude and in the number of observed sectors required to obtain consistent νmax measurements, while maximizing the detectability of oscillations and minimizing the false positive detections. Since νmax is among the crucial seismic parameters to derive precise and accurate stellar masses and radii, the FRA pipeline represents a huge potential for Galactic archeology and exoplanet characterization.

Published
2022
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18. A 20 Second Cadence View of Solar-type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Recharacterization of π Men c

Author

Huber, Daniel, primary, White, Timothy R., additional, Metcalfe, Travis S., additional, Chontos, Ashley, additional, Fausnaugh, Michael M., additional, Ho, Cynthia S. K., additional, Van Eylen, Vincent, additional, Ball, Warrick H., additional, Basu, Sarbani, additional, Bedding, Timothy R., additional, Benomar, Othman, additional, Bossini, Diego, additional, Breton, Sylvain, additional, Buzasi, Derek L., additional, Campante, Tiago L., additional, Chaplin, William J., additional, Christensen-Dalsgaard, Jørgen, additional, Cunha, Margarida S., additional, Deal, Morgan, additional, García, Rafael A., additional, García Muñoz, Antonio, additional, Gehan, Charlotte, additional, González-Cuesta, Lucía, additional, Jiang, Chen, additional, Kayhan, Cenk, additional, Kjeldsen, Hans, additional, Lundkvist, Mia S., additional, Mathis, Stéphane, additional, Mathur, Savita, additional, Monteiro, Mário J. P. F. G., additional, Nsamba, Benard, additional, Ong, Jia Mian Joel, additional, Pakštienė, Erika, additional, Serenelli, Aldo M., additional, Silva Aguirre, Victor, additional, Stassun, Keivan G., additional, Stello, Dennis, additional, Norgaard Stilling, Sissel, additional, Lykke Winther, Mark, additional, Wu, Tao, additional, Barclay, Thomas, additional, Daylan, Tansu, additional, Günther, Maximilian N., additional, Hermes, J. J., additional, Jenkins, Jon M., additional, Latham, David W., additional, Levine, Alan M., additional, Ricker, George R., additional, Seager, Sara, additional, Shporer, Avi, additional, Twicken, Joseph D., additional, Vanderspek, Roland K., additional, and Winn, Joshua N., additional

Published
2022
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19. Asteroseismic measurement of the inclination angle: characterizing exoplanetary systems

Author

Gehan, Charlotte, Benoit Mosser, Eric Michel, and Margarida Cunha

Subjects
Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Information on stellar inclinations are of prime importance to characterize the formation and dynamics of transiting exoplanetarysystems, by helping to constrain the angle between the stellar spin axis and the planetaryorbit axis, namely theobliquity. As PLATO will observe about 150 000 main-sequence stars potentially hostingexoplanets, it is crucial to have at hand afast, robust and automated method to measure the stellar inclination angle. I will present the method I developed and the results I derived for almost 1200 red giant stars that have beenobserved by the Keplerspace mission, which exhibit mixed modes offering the opportunity to obtain accurate measurements of the inclination angleof the stellar rotation axis. I could characterize the biases affecting inclinationmeasurements, in particular for extreme valuesclose to 0 ◦ and 90 ◦ . This study allowed me to provide a way to inferthe underlying statistical distribution of inclinations for agiven sample of stars, free from observational limitations.This method has the advantage to be able to deriveseismicmeasurements of theinclination angle for any solar-typepulsator with identified oscillation modes.

Published
2021
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20. Rapidly rotating red giants

Author

Gehan Charlotte, Mosser Benoît, and Michel Eric

Subjects
Physics, QC1-999
Abstract

Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, wich behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high–quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the identification of mode crossings is precise and efficient. The determination of the mean core rotation directly derives from the precise measurement of the asymptotic period spacing ΔΠ1 and of the frequency at which the crossing of the rotational components is observed.

Published
2017
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21. Evolution de la rotation du cœur des étoiles sur la branche des géantes rouges : des mesures à grande échelle vers une caractérisation du transport de moment cinétique

Author

Gehan, Charlotte, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris – LESIA, Benoît Mosser(Benoit.Mosser@obspm.fr), Eric Michel, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PSL Research University, Benoît Mosser, and Université Paris sciences et lettres

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Rotation interne, Stellar physics, Data analysis, Asteroseismology, Géantes rouges, Internal rotation, Stellar physics - Asteroseismology - Red giants - Internal rotation - Angular momentum transport - Data analysis - Modelling, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astérosismologie, Modelling, Red giants, Physique stellaire, Modélisation, Physique stellaire - Astérosismologie - Géantes rouges - Rotation interne - Transport de moment cinétique - Traitement de données - Modélisation, Traitement de données
Abstract

Asteroseismology consists in probing stellar interiors through the detection of seismic waves. Red giants are evolved low-mass stars that have exhausted hydrogen in their core. These stars are solar-type pulsators presenting mixed modes that allow us to have a direct access to the physical properties of their core. The available seismic measurements indicate that one or several mechanisms that remain poorly understood counterbalance the acceleration ofthe core rotation, resulting from its contraction, by transporting angularmomentum. The greatest part of this PhD thesis was devoted to the development of a method allowing a measurement as automated as possible of the mean core rotation of stars on the red giant branch that were observed by the Kepler satellite (NASA). The measurements that were derived for almost 900 stars highlight that the core rotation is almost constant along the red giant branch, with values largely independent of the stellar mass. The second part of this PhD thesis is devoted to the interpretation of these results based on stellar modelling. The challenge consists in using the large-scale measurements obtainedin the first part to characterise the quantity of angular momentum that has to be extracted from each layer of the core, at different timesteps on the red giant branch, for different stellar masses.; L’astérosismologie consiste à sonder les intérieurs stellaires en détectant les ondes sismiques qui s’y propagent. Les géantes rouges, des étoiles évoluées peu massives dont l’hydrogène du cœur est épuisé, sont des pulsateurs de type solaire présentant des modes mixtes qui nous permettent d’accéder directement aux propriétés physiques de leur cœur. Les mesures sismiques disponibles indiquent qu’un ou plusieurs mécanismes physiques encore mal compris contrebalancent l’accélération de la rotation du cœur sous l’effet de sa contraction, en transportant du moment cinétique. La majeure partie de cette thèse a été consacrée au développement d’une méthode permettant une mesure aussi automatisée que possible de la rotation moyenne du cœur des étoiles de la branche des géantes rouges observées par le satellite Kepler (NASA). Les mesures obtenues pour environ 900 étoiles mettent en évidence que la rotation du cœur est à peu près constante le long de la branche des géantes rouges,avec des valeurs indépendantes de la masse des étoiles. Le deuxième volet de cette thèse est consacré à l’interprétation de ces résultats basée sur la modélisation stellaire. L’enjeu consiste à utiliser les mesures à grande échelle obtenues durant la première partie pour caractériser la quantité de moment cinétique qui doit être extraite localement de chaque région du cœur, à différents instants sur la branche des géantes rouges, pour différentes masses stellaires.

Published
2018

22. Cover Picture: Astron. Nachr. 05/2023.

Author

Gehan, Charlotte, Campante, T. L., Cunha, M. S., and Pereira, F.

Subjects
*FREQUENCIES of oscillating systems, *RED giants
Abstract

The left panel shows the raw spectrum, where the frequency of the maximum oscillation power, SB max sb , is indicated by two almost coincident vertical lines corresponding to the reference measurement (dashed red and the measurement with the new FRA pipeline (solid black), respectively. Oscillation power spectrum of the Kepler red giant KIC 1027337. The new Fast, Robust, and Automated (FRA) tool for the detection and measurement of solar-like oscillations in time-series photometry of red-giant stars is described, tested, and validated in detail in the paper by Gehan et al., this issue, e220090. [Extracted from the article]

Published
2023
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