Browsing by Author "Tuomi, Mikko"

Now showing items 1-20 of 58

    • AD Leonis : Radial velocity signal of stellar rotation or spin-orbit resonance? 

      Tuomi, Mikko; Jones, Hugh R. A.; Anglada-Escudé, Guillem; Butler, R. Paul; Kiraga, Marcin; Vogt, Steven S. (2018-04-16)
      AD Leonis is a nearby magnetically active M dwarf. We find Doppler variability with a period of 2.23 days, as well as photometric signals: (1) a short-period signal, which is similar to the radial velocity signal, albeit ...

    • Agatha: : disentangling periodic signals from correlated noise in a periodogram framework 

      Feng, Fabo; Tuomi, Mikko; Jones, Hugh R. A. (2017-10-01)
      Periodograms are used as a key significance assessment and visualisation tool to display the significant periodicities in unevenly sampled time series. We introduce a framework of periodograms, called "Agatha", to disentangle ...

    • Analysis of combined radial velocities and activity of BD+20 1790: : evidence supporting the existence of a planetary companion 

      Hernán-Obispo, M.; Tuomi, Mikko; Gálvez-Ortiz, M. C.; Golovin, A.; Barnes, J. R.; Jones, Hugh; Kane, S. R.; Pinfield, D.; Jenkins, J. S.; Petit, P.; Anglada-Escudé, G.; Marsden, S. C.; Catalán, S.; Jeffers, S. V.; Castro, E. de; Cornide, M.; Garcés, A.; Jones, M. I.; Gorlova, N.; Andreev, M. (2015-04-01)
      This paper presents the simultaneous Bayesian analysis of the radial velocity and activity indices for the K5Ve active star BD+20 1790, that was proposed to host a close-in massive planet by Hern\'an-Obispo et al. (2010). ...

    • The Anglo-Australian planet search. XXII : Two new multi-planet systems 

      Wittenmyer, Robert A.; Horner, J.; Tuomi, Mikko; Salter, G. S.; Tinney, C.G.; Butler, R. P.; Jones, H.R.A.; O'Toole, S. J.; Bailey, J.; Carter, B. D.; Jenkins, J. S.; Zhang, Z.; Vogt, S. S.; Rivera, Eugenio J. (2012-07-10)
      We report the detection of two new planets from the Anglo-Australian Planet Search. These planets orbit two stars each previously known to host one planet. The new planet orbiting HD 142 has a period of 6005 +/- 427 days, ...

    • The Anglo-Australian planet search. XXIII. Two new jupiter analogs 

      Wittenmyer, Robert A.; Horner, Jonathan; Tinney, C. G.; Butler, R. P.; Jones, H. R A; Salter, G. S.; Carter, B. D.; Koch, F. Elliott; O'Toole, S. J.; Bailey, J.; Wright, D.; Tuomi, Mikko (2014-03-10)
      We report the discovery of two long-period giant planets from the Anglo-Australian Planet Search. HD 154857c is in a multiple-planet system, while HD 114613b appears to be solitary. HD 114613b has an orbital period P = ...

    • Bayesian analysis of the radial velocities of HD 11506 reveals another planetary companion 

      Tuomi, Mikko; Kotiranta, S. (2009-03-01)
      Aims. We aim to demonstrate the efficiency of a Bayesian approach in analysing radial velocity data by reanalysing a set of radial velocity measurements. Methods. We present Bayesian analysis of a recently published set ...

    • Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics 

      Tuomi, Mikko; Jones, Hugh; Barnes, John R.; Anglada-Escudé, Guillem; Jenkins, James S. (2014-06-21)
      Due to their higher planet-star mass ratios, M dwarfs are the easiest targets for detection of low-mass planets orbiting nearby stars using Doppler spectroscopy. Furthermore, because of their low masses and luminosities, ...

    • Benchmarking the power of amateur observatories for TTV exoplanets detection 

      Baluev, Roman V.; Sokov, Evgenii N.; Shaidulin, Vakhit Sh; Sokova, Iraida A.; Jones, H.R.A.; Tuomi, Mikko; Anglada-Escudé, Guillem; Benni, Paul; Colazo, Carlos A.; Schneiter, Matias E.; D'Angelo, Carolina S. Villarreal; Burdanov, Artem Yu; Fernández-Lajús, Eduardo; Baştürk, Özgür; Hentunen, Veli-Pekka; Shadick, Stan (2015-07-01)
      We perform an analysis of ~80000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit ...

    • Carbon stock changes of forest land in Finland under different levels of wood use and climate change 

      Sievänen, Risto; Salminen, Olli; Lehtonen, Aleksi; Ojanen, Paavo; Liski, Jari; Ruosteenoja, Kimmo; Tuomi, Mikko (2014-03-01)
      •Context: Prediction of the effect of harvests and climate change (CC) on the changes in carbon stock of forests is necessary both for CC mitigation and adaptation purposes. •Aims: We assessed the impact of roundwood and ...

    • Color difference makes a difference: four planet candidates around tau Ceti 

      Feng, F.; Tuomi, Mikko; Jones, Hugh; Barnes, J.; Anglada-Escude, G.; Vogt, S. S.; Butler, R. P. (2017-09-05)
      The removal of noise typically correlated in time and wavelength is one of the main challenges for using the radial velocity method to detect Earth analogues. We analyze radial velocity data of tau Ceti and find robust ...

    • Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581" 

      Tuomi, Mikko; Anglada-Escude, Guillem (2015-03-06)
      Robertson et al. (Reports, 25 July 2014, p. 440) claimed that activity-induced variability is responsible for the Doppler signal of the proposed planet candidate GJ 581d. We point out that their analysis using periodograms ...

    • The complementarity of astrometrie and radial velocity exoplanet observations: : Determining exoplanet mass with astrometric snapshots 

      Tuomi, Mikko; Kotiranta, S.; Kaasalainen, M. (2009-02)
      Aims. It is commonly assumed that the two indirect exoplanet detection methods, the radial velocity method and astrometric method, require observational periods exceeding the orbital period to produce positive results. ...

    • The curious case of HD 41248. A pair of static signals buried behind red noise 

      Jenkins, J. S.; Tuomi, Mikko (2014-10-20)
      Gaining a better understanding of the effects of stellar-induced radial velocity noise is critical for the future of exoplanet studies since the discovery of the lowest-mass planets using this method will require us to go ...

    • The debris disc of solar analogue Τ Ceti : Herschel observations and dynamical simulations of the proposed multiplanet system 

      Lawler, S. M.; Di Francesco, J.; Kennedy, G. M.; Sibthorpe, B.; Booth, M.; Vandenbussche, B.; Matthews, B. C.; Holland, W. S.; Greaves, J.; Wilner, D. J.; Tuomi, Mikko; Blommaert, J. A D L; De Vries, B. L.; Dominik, C.; Fridlund, M.; Gear, W.; Heras, A. M.; Ivison, R.; Olofsson, G. (2014-11-01)
      Τ Ceti is a nearby, mature G-type star very similar to our Sun, with a massive Kuiper Belt analogue and possible multiplanet system that has been compared to our Solar system. We present Herschel Space Observatory images ...

    • Decomposition and changes in chemical composition of leaf litter of five dominant tree species in a West African tropical forest 

      Guendehou, G. H Sabin; Liski, Jari; Tuomi, Mikko; Moudachirou, Mansourou; Sinsin, Brice; Mäkipää, Raisa (2014-05)
      The objective of the research was to study the rate of decomposition and changes in the chemical characteristics in the leaf litter of selected tree species using a litterbag experiment. The decomposition of leaf litter ...

    • A dense mini-Neptune orbiting the bright young star HD 18599 

      Vines, Jose I.; Jenkins, James S.; Berdiñas, Zaira; Soto, Maritza G.; Díaz, Matías R.; Alves, Douglas R.; Tuomi, Mikko; Wittenmyer, Robert A.; Leon, Jerome Pitogo de; Peña, Pablo; Lissauer, Jack J.; Ballard, Sarah; Bedding, Timothy; Bowler, Brendan P.; Horner, Jonathan; Jones, Hugh R. A.; Kielkopf, John; Plavchan, Peter; Shporer, Avi; Tinney, C. G.; Wright, Hui Zhang Duncan J.; Addison, Brett; Mengel, Matthew W.; Okumura, Jack; Samadi-Ghadim, Anya (2022-10-13)
      Very little is known about the young planet population because the detection of small planets orbiting young stars is obscured by the effects of stellar activity and fast rotation which mask planets within radial velocity ...

    • Detection of the nearest Jupiter analog in radial velocity and astrometry data 

      Feng, Fabo; Anglada-Escudé, Guillem; Tuomi, Mikko; Jones, Hugh R. A.; Chanamé, Julio; Butler, Paul R.; Janson, Markus (2019-10-21)
      The presence of Jupiter is crucial to the architecture of the Solar System and models underline this to be a generic feature of planetary systems. We find the detection of the difference between the position and motion ...

    • A dynamically-packed planetary system around GJ 667C with three super-Earths in its habitable zone 

      Anglada-Escude, Guillem; Tuomi, Mikko; Gerlach, Enrico; Barnes, Rory; Heller, Rene; Jenkins, James S.; Wende, Sebastian; Vogt, Steven S.; Butler, R. Paul; Reiners, Ansgar; Jones, H.R.A. (2013-08-07)
      Context. Since low-mass stars have low luminosities, orbits at which liquid water can exist on Earth-sized planets are relatively close-in, which produces Doppler signals that are detectable using state-of-the-art Doppler ...

    • Evidence for at least three planet candidates orbiting HD20794 

      Feng, Fabo; Tuomi, Mikko; Jones, Hugh R. A. (2017-09-18)
      We explore the feasibility of detecting Earth analogs around Sun-like stars using the radial velocity method by investigating one of the largest radial velocities datasets for the one of the most stable radial-velocity ...

    • Evidence for nine planets in the HD 10180 system 

      Tuomi, Mikko (2012-07-01)
      Aims. We re-analyse the HARPS radial velocities of HD 10180 and calculate the probabilities of models with differing numbers of periodic signals in the data. We test the significance of the seven signals, corresponding to ...