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Damasso M, Del Sordo F, Anglada-Escudé G, Giacobbe P, Sozzetti A, Morbidelli A, Pojmanski G, Barbato D, Butler RP, Jones HRA, Hambsch FJ, Jenkins JS, López-González MJ, Morales N, Peña Rojas PA, Rodríguez-López C, Rodríguez E, Amado PJ, Anglada G, Feng F, Gómez JF. A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU. SCIENCE ADVANCES 2020; 6:eaax7467. [PMID: 31998838 PMCID: PMC6962037 DOI: 10.1126/sciadv.aax7467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 10/31/2019] [Indexed: 06/10/2023]
Abstract
Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass m c sin i c = 5.8 ± 1.9M ⊕ and orbital period P c = 5.21 - 0.22 + 0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.
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Affiliation(s)
- Mario Damasso
- INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
| | - Fabio Del Sordo
- Department of Physics, University of Crete, Voutes, 70013 Heraklion, Greece
- Institute of Astrophysics, Foundation for Research and Technology-Hellas, PO Box 1527, 71110 Heraklion, Crete, Greece
| | - Guillem Anglada-Escudé
- School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Rd., E14NS London, UK
| | - Paolo Giacobbe
- INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
| | - Alessandro Sozzetti
- INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
| | - Alessandro Morbidelli
- Laboratoire Lagrange, UMR7293, Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, Boulevard de l’Observatoire, 06304, Nice Cedex 4, France
| | - Grzegorz Pojmanski
- Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
| | - Domenico Barbato
- INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
- Dipartimento di Fisica, Universitá degli Studi di Torino, Via Pietro Giuria 1, I-10125 Torino, Italy
| | - R. Paul Butler
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA
| | - Hugh R. A. Jones
- Centre for Astrophysics Research School of Physics, Astronomy and Mathematics University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
| | - Franz-Josef Hambsch
- American Association of Variable Stars Observers, 49 Bay State Road, Cambridge, MA 02138, USA
| | - James S. Jenkins
- Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
| | - María José López-González
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Nicolás Morales
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Pablo A. Peña Rojas
- Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
| | - Cristina Rodríguez-López
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Eloy Rodríguez
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Pedro J. Amado
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Guillem Anglada
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
| | - Fabo Feng
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA
| | - Jose F. Gómez
- Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
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Bollengier O, Brown JM, Shaw GH. Thermodynamics of pure liquid water: Sound speed measurements to 700 MPa down to the freezing point, and an equation of state to 2300 MPa from 240 to 500 K. J Chem Phys 2019. [DOI: 10.1063/1.5097179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Olivier Bollengier
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA
| | - J. Michael Brown
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA
| | - George H. Shaw
- Geology Department, Union College, Schenectady, New York 12308, USA
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Imaging the water snow-line during a protostellar outburst. Nature 2016; 535:258-61. [PMID: 27411631 DOI: 10.1038/nature18612] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/18/2016] [Indexed: 11/08/2022]
Abstract
A snow-line is the region of a protoplanetary disk at which a major volatile, such as water or carbon monoxide, reaches its condensation temperature. Snow-lines play a crucial role in disk evolution by promoting the rapid growth of ice-covered grains. Signatures of the carbon monoxide snow-line (at temperatures of around 20 kelvin) have recently been imaged in the disks surrounding the pre-main-sequence stars TW Hydra and HD163296 (refs 3, 10), at distances of about 30 astronomical units (au) from the star. But the water snow-line of a protoplanetary disk (at temperatures of more than 100 kelvin) has not hitherto been seen, as it generally lies very close to the star (less than 5 au away for solar-type stars). Water-ice is important because it regulates the efficiency of dust and planetesimal coagulation, and the formation of comets, ice giants and the cores of gas giants. Here we report images at 0.03-arcsec resolution (12 au) of the protoplanetary disk around V883 Ori, a protostar of 1.3 solar masses that is undergoing an outburst in luminosity arising from a temporary increase in the accretion rate. We find an intensity break corresponding to an abrupt change in the optical depth at about 42 au, where the elevated disk temperature approaches the condensation point of water, from which we conclude that the outburst has moved the water snow-line. The spectral behaviour across the snow-line confirms recent model predictions: dust fragmentation and the inhibition of grain growth at higher temperatures results in soaring grain number densities and optical depths. As most planetary systems are expected to experience outbursts caused by accretion during their formation, our results imply that highly dynamical water snow-lines must be considered when developing models of disk evolution and planet formation.
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