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1. The magnetic propeller accretion regime of LkCa 15

Author

Donati, J-F, Bouvier, J, Alencar, SH, Hill, C, Carmona, A, Folsom, CP, Menard, F, Gregory, SG, Hussain, GA, Grankin, K, Moutou, C, Malo, L, Takami, M, Herczeg, GJ, and collaboration, the MaTYSSE

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We present a spectropolarimetric study of the classical T Tauri star (cTTS) LkCa 15 investigating the large-scale magnetic topology of the central star and the way the field connects to the inner regions of the accretion disc. We find that the star hosts a strong poloidal field with a mainly axisymmetric dipole component of 1.35 kG, whereas the mass accretion rate at the surface of the star is $10^{-9.2}$ $\hbox{${\rm M}_{\odot}$ yr$^{-1}$}$. It implies that the magnetic field of LkCa 15 is able to evacuate the central regions of the disc up to a distance of 0.07 au at which the Keplerian orbital period equals the stellar rotation period. Our results suggest that LkCa 15, like the lower-mass cTTS AA Tau, interacts with its disc in a propeller mode, a regime supposedly very efficient at slowing down the rotation of cTTSs hosting strong dipolar fields., Comment: MNRAS letter, in press (3 figures, 1 table)

Published
2018
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2. I. Survey presentation and accretion properties of Orion OB1 and σ -Orionis

Author

Manara, CF, Frasca, A, Venuti, L, Siwak, M, Herczeg, GJ, Calvet, N, Hernandez, J, Tychoniec, Ł, Gangi, M, Alcalá, JM, Boffin, HMJ, Nisini, B, Robberto, M, Briceno, C, Campbell-White, J, Sicilia-Aguilar, A, McGinnis, P, Fedele, D, Kóspál, Á, Ábrahám, P, Alonso-Santiago, J, Antoniucci, S, Arulanantham, N, Bacciotti, F, Banzatti, A, Beccari, G, Benisty, M, Biazzo, K, Bouvier, J, Cabrit, S, Caratti o Garatti, A, Coffey, D, Covino, E, Dougados, C, Eislöffel, J, Ercolano, B, Espaillat, CC, Erkal, J, Facchini, S, Fang, M, Fiorellino, E, Fischer, WJ, France, K, Gameiro, JF, Garcia Lopez, R, Giannini, T, Ginski, C, Grankin, K, Günther, HM, Hartmann, L, Hillenbrand, LA, Hussain, GAJ, James, MM, Koutoulaki, M, Lodato, G, Maucó, K, Mendigutía, I, Mentel, R, Miotello, A, Oudmaijer, RD, Rigliaco, E, Rosotti, GP, Sanchis, E, Schneider, PC, Spina, L, Stelzer, B, Testi, L, Thanathibodee, T, Vink, JS, Walter, FM, Williams, JP, Zsidi, G, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
stars: variables: T Tauri, [PHYS]Physics [physics], accretion, accretion disks, protoplanetary disks, Herbig Ae/Be, Astrophysics::Solar and Stellar Astrophysics, stars: pre-main sequence, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

International audience; The evolution of young stars and disks is driven by the interplay of several processes, notably the accretion and ejection of material. These processes, critical to correctly describe the conditions of planet formation, are best probed spectroscopically. Between 2020 and 2022, about 500orbits of the Hubble Space Telescope (HST) are being devoted in to the ULLYSES public survey of about 70 low-mass ( M ⋆ ≤ 2 M ⊙ ) young (age < 10 Myr) stars at UV wavelengths. Here, we present the PENELLOPE Large Program carried out with the ESO Very Large Telescope (VLT) with the aim of acquiring, contemporaneously to the HST, optical ESPRESSO/UVES high-resolution spectra for the purpose of investigating the kinematics of the emitting gas, along with UV-to-NIR X-shooter medium-resolution flux-calibrated spectra to provide the fundamental parameters that HST data alone cannot provide, such as extinction and stellar properties. The data obtained by PENELLOPE have no proprietary time and the fully reduced spectra are being made available to the whole community. Here, we describe the data and the first scientific analysis of the accretion properties for the sample of 13 targets located in the Orion OB1 association and in the σ -Orionis cluster, observed in November–December 2020. We find that the accretion rates are in line with those observed previously in similarly young star-forming regions, with a variability on a timescale of days (≲3). The comparison of the fits to the continuum excess emission obtained with a slab model on the X-shooter spectra and the HST/STIS spectra shows a shortcoming in the X-shooter estimates of ≲10%, which is well within the assumed uncertainty. Its origin can be either due to an erroneous UV extinction curve or to the simplicity of the modeling and, thus, this question will form the basis of the investigation undertaken over the course of the PENELLOPE program. The combined ULLYSES and PENELLOPE data will be key in attaining a better understanding of the accretion and ejection mechanisms in young stars.

Published
2021
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3. The magnetic propeller accretion regime of LkCa 15

Author

Donati, J-F, Bouvier, J, Alencar, SH, Hill, C, Carmona, A, Folsom, CP, Menard, F, Gregory, SG, Hussain, GA, Grankin, K, Moutou, C, Malo, L, Takami, M, Herczeg, GJ, collaboration, the MaTYSSE, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), University of St Andrews [Scotland], Crimean Astrophysical Observatory (CrAO), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Academia Sinica, Max-Planck-Institut für Extraterrestrische Physik (MPE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Rotational symmetry, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Accretion rate, 0103 physical sciences, stars: magnetic fields, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Stellar rotation, Astronomy and Astrophysics, Orbital period, Accretion (astrophysics), stars: imaging, Magnetic field, Dipole, T Tauri star, techniques: polarimetric, Astrophysics - Solar and Stellar Astrophysics, stars: individual: LkCa 15, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics
Abstract

We present a spectropolarimetric study of the classical T Tauri star (cTTS) LkCa 15 investigating the large-scale magnetic topology of the central star and the way the field connects to the inner regions of the accretion disc. We find that the star hosts a strong poloidal field with a mainly axisymmetric dipole component of 1.35 kG, whereas the mass accretion rate at the surface of the star is $10^{-9.2}$ $\hbox{${\rm M}_{\odot}$ yr$^{-1}$}$. It implies that the magnetic field of LkCa 15 is able to evacuate the central regions of the disc up to a distance of 0.07 au at which the Keplerian orbital period equals the stellar rotation period. Our results suggest that LkCa 15, like the lower-mass cTTS AA Tau, interacts with its disc in a propeller mode, a regime supposedly very efficient at slowing down the rotation of cTTSs hosting strong dipolar fields., Comment: MNRAS letter, in press (3 figures, 1 table)

Published
2019
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4. A Large Double-ring Disk Around the Taurus M Dwarf J04124068+2438157

Author

Feng Long, Bin B. Ren, Nicole L. Wallack, Daniel Harsono, Gregory J. Herczeg, Paola Pinilla, Dimitri Mawet, Michael C. Liu, Sean M. Andrews, Xue-Ning Bai, Sylvie Cabrit, Lucas A. Cieza, Doug Johnstone, Jarron M. Leisenring, Giuseppe Lodato, Yao Liu, Carlo F. Manara, Gijs D. Mulders, Enrico Ragusa, Steph Sallum, Yangfan Shi, Marco Tazzari, Taichi Uyama, Kevin Wagner, David J. Wilner, Jerry W. Xuan, Long, F [0000-0002-7607-719X], Ren, BB [0000-0003-1698-9696], Wallack, NL [0000-0003-0354-0187], Harsono, D [0000-0001-6307-4195], Herczeg, GJ [0000-0002-7154-6065], Pinilla, P [0000-0001-8764-1780], Mawet, D [0000-0002-8895-4735], Liu, MC [0000-0003-2232-7664], Andrews, SM [0000-0003-2253-2270], Bai, XN [0000-0001-6906-9549], Cabrit, S [0000-0002-1593-3693], Cieza, LA [0000-0002-2828-1153], Johnstone, D [0000-0002-6773-459X], Leisenring, JM [0000-0002-0834-6140], Lodato, G [0000-0002-2357-7692], Manara, CF [0000-0003-3562-262X], Mulders, GD [0000-0002-1078-9493], Ragusa, E [0000-0001-5378-7749], Sallum, S [0000-0001-6871-6775], Shi, Y [0000-0001-9277-6495], Tazzari, M [0000-0003-3590-5814], Uyama, T [0000-0002-6879-3030], Wagner, K [0000-0002-4309-6343], Wilner, DJ [0000-0003-1526-7587], Xuan, JW [0000-0002-6618-1137], and Apollo - University of Cambridge Repository

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, 5109 Space Sciences, 51 Physical Sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

Planet formation imprints signatures on the physical structures of disks. In this paper, we present high-resolution ($\sim$50 mas, 8 au) Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and CO line emission toward the disk around the M3.5 star 2MASS J04124068+2438157. The dust disk consists only of two narrow rings at radial distances of 0.47 and 0.78 arcsec ($\sim$70 and 116 au), with Gaussian $\sigma$ widths of 5.6 and 8.5 au, respectively. The width of the outer ring is smaller than the estimated pressure scale height by $\sim25\%$, suggesting dust trapping in a radial pressure bump. The dust disk size, set by the location of the outermost ring, is significantly larger (by $3\sigma$) than other disks with similar millimeter luminosity, which can be explained by an early formation of local pressure bump to stop radial drift of millimeter dust grains. After considering the disk's physical structure and accretion properties, we prefer planet--disk interaction over dead zone or photoevaporation models to explain the observed dust disk morphology. We carry out high-contrast imaging at $L'$ band using Keck/NIRC2 to search for potential young planets, but do not identify any source above $5\sigma$. Within the dust gap between the two rings, we reach a contrast level of $\sim$7 mag, constraining the possible planet below $\sim$2--4 $M_{\rm Jup}$. Analyses of the gap/ring properties suggest a $\sim$Saturn mass planet at $\sim$90 au is likely responsible for the formation of the outer ring, which can be potentially revealed with JWST., Comment: 15 pages, 5 figures. Accepted for publication in ApJ

Published
2023

5. A major asymmetric dust trap in a transition disk.

Author

van der Marel N, van Dishoeck EF, Bruderer S, Birnstiel T, Pinilla P, Dullemond CP, van Kempen TA, Schmalzl M, Brown JM, Herczeg GJ, Mathews GS, and Geers V

Abstract

The statistics of discovered exoplanets suggest that planets form efficiently. However, there are fundamental unsolved problems, such as excessive inward drift of particles in protoplanetary disks during planet formation. Recent theories invoke dust traps to overcome this problem. We report the detection of a dust trap in the disk around the star Oph IRS 48 using observations from the Atacama Large Millimeter/submillimeter Array (ALMA). The 0.44-millimeter-wavelength continuum map shows high-contrast crescent-shaped emission on one side of the star, originating from millimeter-sized grains, whereas both the mid-infrared image (micrometer-sized dust) and the gas traced by the carbon monoxide 6-5 rotational line suggest rings centered on the star. The difference in distribution of big grains versus small grains/gas can be modeled with a vortex-shaped dust trap triggered by a companion.

Published
2013
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