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Jeffers SV, Dreizler S, Barnes JR, Haswell CA, Nelson RP, Rodríguez E, López-González MJ, Morales N, Luque R, Zechmeister M, Vogt SS, Jenkins JS, Palle E, Berdi Ñas ZM, Coleman GAL, Díaz MR, Ribas I, Jones HRA, Butler RP, Tinney CG, Bailey J, Carter BD, O'Toole S, Wittenmyer RA, Crane JD, Feng F, Shectman SA, Teske J, Reiners A, Amado PJ, Anglada-Escudé G. A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887. Science 2020; 368:1477-1481. [PMID: 32587019 DOI: 10.1126/science.aaz0795] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 05/12/2020] [Indexed: 11/02/2022]
Abstract
The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf.
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Affiliation(s)
- S V Jeffers
- Institut für Astrophysik, Georg-August-UniversitÄt, 37077 Göttingen, Germany.
| | - S Dreizler
- Institut für Astrophysik, Georg-August-UniversitÄt, 37077 Göttingen, Germany
| | - J R Barnes
- School of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - C A Haswell
- School of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - R P Nelson
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK
| | - E Rodríguez
- Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - M J López-González
- Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - N Morales
- Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - R Luque
- Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain.,Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
| | - M Zechmeister
- Institut für Astrophysik, Georg-August-UniversitÄt, 37077 Göttingen, Germany
| | - S S Vogt
- University of California/Lick Observatory, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - J S Jenkins
- Departamento de Astronomia, Universidad de Chile, Santiago, Chile.,Centro de Astrofísica y Tecnologías Afines, Santiago, Chile
| | - E Palle
- Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain.,Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
| | - Z M Berdi Ñas
- Departamento de Astronomia, Universidad de Chile, Santiago, Chile
| | - G A L Coleman
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK.,Physikalisches Institut, UniversitÄt Bern, 3012 Bern, Switzerland
| | - M R Díaz
- Departamento de Astronomia, Universidad de Chile, Santiago, Chile
| | - I Ribas
- Institut de Ciències de l'Espai, Consejo Superior de Investigaciones Científicas, Campus Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.,Istitut d'Estudis Espacials de Catalunya, E-08034 Barcelona, Spain
| | - H R A Jones
- Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - R P Butler
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - C G Tinney
- Exoplanetary Science at University of New South Wales, School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
| | - J Bailey
- Exoplanetary Science at University of New South Wales, School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
| | - B D Carter
- Centre for Astrophysics, University of Southern Queensland, Springfield Central, QLD 4300, Australia
| | - S O'Toole
- Australian Astronomical Optics, Macquarie University, North Ryde, NSW 2113, Australia
| | - R A Wittenmyer
- Centre for Astrophysics, University of Southern Queensland, Toowoomba, QLD 4350, Australia
| | - J D Crane
- The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101, USA
| | - F Feng
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA
| | - S A Shectman
- The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101, USA
| | - J Teske
- The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101, USA
| | - A Reiners
- Institut für Astrophysik, Georg-August-UniversitÄt, 37077 Göttingen, Germany
| | - P J Amado
- Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - G Anglada-Escudé
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK.,Institut de Ciències de l'Espai, Consejo Superior de Investigaciones Científicas, Campus Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.,Istitut d'Estudis Espacials de Catalunya, E-08034 Barcelona, Spain
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2
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Ribas I, Tuomi M, Reiners A, Butler RP, Morales JC, Perger M, Dreizler S, Rodríguez-López C, González Hernández JI, Rosich A, Feng F, Trifonov T, Vogt SS, Caballero JA, Hatzes A, Herrero E, Jeffers SV, Lafarga M, Murgas F, Nelson RP, Rodríguez E, Strachan JBP, Tal-Or L, Teske J, Toledo-Padrón B, Zechmeister M, Quirrenbach A, Amado PJ, Azzaro M, Béjar VJS, Barnes JR, Berdiñas ZM, Burt J, Coleman G, Cortés-Contreras M, Crane J, Engle SG, Guinan EF, Haswell CA, Henning T, Holden B, Jenkins J, Jones HRA, Kaminski A, Kiraga M, Kürster M, Lee MH, López-González MJ, Montes D, Morin J, Ofir A, Pallé E, Rebolo R, Reffert S, Schweitzer A, Seifert W, Shectman SA, Staab D, Street RA, Suárez Mascareño A, Tsapras Y, Wang SX, Anglada-Escudé G. A candidate super-Earth planet orbiting near the snow line of Barnard’s star. Nature 2018; 563:365-368. [DOI: 10.1038/s41586-018-0677-y] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/01/2018] [Indexed: 11/09/2022]
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3
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Marsh TR, Gänsicke BT, Hümmerich S, Hambsch FJ, Bernhard K, Lloyd C, Breedt E, Stanway ER, Steeghs DT, Parsons SG, Toloza O, Schreiber MR, Jonker PG, van Roestel J, Kupfer T, Pala AF, Dhillon VS, Hardy LK, Littlefair SP, Aungwerojwit A, Arjyotha S, Koester D, Bochinski JJ, Haswell CA, Frank P, Wheatley PJ. A radio-pulsing white dwarf binary star. Nature 2016; 537:374-377. [PMID: 27462808 DOI: 10.1038/nature18620] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/25/2016] [Indexed: 11/09/2022]
Abstract
White dwarfs are compact stars, similar in size to Earth but approximately 200,000 times more massive. Isolated white dwarfs emit most of their power from ultraviolet to near-infrared wavelengths, but when in close orbits with less dense stars, white dwarfs can strip material from their companions and the resulting mass transfer can generate atomic line and X-ray emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic. However, even in binaries, white dwarfs are rarely detected at far-infrared or radio frequencies. Here we report the discovery of a white dwarf/cool star binary that emits from X-ray to radio wavelengths. The star, AR Scorpii (henceforth AR Sco), was classified in the early 1970s as a δ-Scuti star, a common variety of periodic variable star. Our observations reveal instead a 3.56-hour period close binary, pulsing in brightness on a period of 1.97 minutes. The pulses are so intense that AR Sco's optical flux can increase by a factor of four within 30 seconds, and they are also detectable at radio frequencies. They reflect the spin of a magnetic white dwarf, which we find to be slowing down on a 107-year timescale. The spin-down power is an order of magnitude larger than that seen in electromagnetic radiation, which, together with an absence of obvious signs of accretion, suggests that AR Sco is primarily spin-powered. Although the pulsations are driven by the white dwarf's spin, they mainly originate from the cool star. AR Sco's broadband spectrum is characteristic of synchrotron radiation, requiring relativistic electrons. These must either originate from near the white dwarf or be generated in situ at the M star through direct interaction with the white dwarf's magnetosphere.
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Affiliation(s)
- T R Marsh
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - B T Gänsicke
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - S Hümmerich
- Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV), Berlin, Germany.,American Association of Variable Star Observers (AAVSO), Cambridge, Massachusetts, USA
| | - F-J Hambsch
- Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV), Berlin, Germany.,American Association of Variable Star Observers (AAVSO), Cambridge, Massachusetts, USA.,Vereniging Voor Sterrenkunde (VVS), Brugge, Belgium
| | - K Bernhard
- Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV), Berlin, Germany.,American Association of Variable Star Observers (AAVSO), Cambridge, Massachusetts, USA
| | - C Lloyd
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, UK
| | - E Breedt
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - E R Stanway
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - D T Steeghs
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - S G Parsons
- Instituto de Física y Astronomía, Universidad de Valparaíso, Avenida Gran Bretana 1111, Valparaíso, Chile
| | - O Toloza
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - M R Schreiber
- Instituto de Física y Astronomía, Universidad de Valparaíso, Avenida Gran Bretana 1111, Valparaíso, Chile
| | - P G Jonker
- SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht, The Netherlands.,Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - J van Roestel
- Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - T Kupfer
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - A F Pala
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
| | - V S Dhillon
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK.,Instituto de Astrofisica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain.,Universidad de La Laguna, Departamento Astrofisica, E-38206 La Laguna, Tenerife, Spain
| | - L K Hardy
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
| | - S P Littlefair
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
| | - A Aungwerojwit
- Department of Physics, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand
| | - S Arjyotha
- Program of Physics, Faculty of Science and Technology, Chiang Rai Rajabhat University, Chiang Rai 57100, Thailand
| | - D Koester
- Institut für Theoretische Physik und Astrophysik, University of Kiel, 24098 Kiel, Germany
| | - J J Bochinski
- Department of Physical Sciences, The Open University, Milton Keynes, UK
| | - C A Haswell
- Department of Physical Sciences, The Open University, Milton Keynes, UK
| | - P Frank
- Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV), Berlin, Germany
| | - P J Wheatley
- Department of Physics, Gibbet Hill Road, University of Warwick, Coventry CV4 7AL, UK
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Llama J, Wood K, Jardine M, Vidotto AA, Helling C, Fossati L, Haswell CA. The shocking transit of WASP-12b: modelling the observed early ingress in the near-ultraviolet. ACTA ACUST UNITED AC 2011. [DOI: 10.1111/j.1745-3933.2011.01093.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cui W, Shrader CR, Haswell CA, Hynes RI. Discovery of High-Frequency Quasi-periodic Oscillations in the Black Hole Candidate XTE J1859+226. Astrophys J 2000; 535:L123-L127. [PMID: 10835314 DOI: 10.1086/312712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2000] [Accepted: 04/17/2000] [Indexed: 05/23/2023]
Abstract
We report the discovery of quasi-periodic oscillations (QPOs) at roughly 187 and 150 Hz in the X-ray intensity of X-ray nova XTE J1859+226. The source was observed during a recent outburst with the Rossi X-Ray Timing Explorer. Besides these high-frequency QPOs, we have also detected QPOs (and sometimes their harmonics) at 6-7 Hz and significant broadband variability at low frequencies. These properties, as well as the observed hard X-ray spectrum, make XTE J1859+226 a black hole candidate (BHC). The detection of QPOs at two distinct frequencies greater, similar100 Hz in two observations separated by about 4 hr provide additional insights into the high-frequency QPO phenomenon in BHCs. The importance lies in the proposed interpretations, which invariably involve the effects of strong gravity near a black hole. We compare our results to those of other BHCs and discuss the impact of the observational data on the models in a global context.
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