DOCSLIB.ORG

The HARPS Search for Southern Extra-Solar Planets

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The HARPS Search for Southern Extra-Solar Planets A&A 437, 1121–1126 (2005) Astronomy DOI: 10.1051/0004-6361:20052864 & c ESO 2005 Astrophysics The HARPS search for southern extra-solar planets III. Three Saturn-mass planets around HD 93083, HD 101930 and HD 102117 C. Lovis1, M. Mayor1, F. Bouchy2,F.Pepe1,D.Queloz1,N.C.Santos3,1, S. Udry1,W.Benz4, J.-L. Bertaux5, C. Mordasini4, and J.-P. Sivan2 1 Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland e-mail: [email protected] 2 Laboratoire d’Astrophysique de Marseille, Traverse du Siphon, 13013 Marseille, France 3 Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal 4 Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 5 Service d’Aéronomie du CNRS, BP 3, 91371 Verrières-le-Buisson, France Received 11 February 2005 / Accepted 16 March 2005 Abstract. We report on the detection of three Saturn-mass planets discovered with the HARPS instrument. HD 93083 shows radial-velocity (RV) variations best explained by the presence of a companion of 0.37 MJup orbiting in 143.6 days. HD 101930 b has an orbital period of 70.5 days and a minimum mass of 0.30 MJup. For HD 102117, we present the independent detection of a companion with m2 sin i = 0.14 MJup and orbital period P = 20.7 days. This planet was recently detected by Tinney et al. (2004, ApJ, submitted). Activity and bisector indicators exclude any significant RV perturbations of stellar origin, reinforcing the planetary interpretation of the RV variations. The radial-velocity residuals around the Keplerian fits are 2.0, 1.8 and 0.9 m s−1 respectively, showing the unprecedented RV accuracy achieved with HARPS. A sample of stable stars observed with HARPS is also presented to illustrate the long-term precision of the instrument. All three stars are metal-rich, confirming the now well- established relation between planet occurrence and metallicity. The new planets are all in the Saturn-mass range, orbiting at moderate distance from their parent star, thereby occupying an area of the parameter space which seems difficult to populate according to planet formation theories. A systematic exploration of these regions will provide new constraints on formation scenarios in the near future. Key words. stars: individual: HD 93083 – stars: individual: HD 101930 – stars: individual: HD 102117 – stars: planetary systems – techniques: radial velocities – techniques: spectroscopic 1. Introduction characterization of long-period planets and complex planetary systems. The low-mass and long-period regions of the exo- The HARPS instrument is the new ESO high-resolution (R = planet parameter space will therefore be under close scrutiny in 115 000) fiber-fed echelle spectrograph, mainly dedicated to the coming months and years. This will improve our knowledge planet search programmes and asteroseismology. It has already of the planet distribution in the mass-period diagram and will proved to be the most precise spectro-velocimeter to date, allow comparisons with theoretical predictions (see for exam- reaching an instrumental RV accuracy of ∼1ms−1 (Mayor ple Armitage et al. 2002; Ida & Lin 2004; Alibert et al. 2005). et al. 2003; Pepe et al. 2004; Santos et al. 2004a), and even In this paper we present the discovery of three plane- better on a short-term basis. This opens a new field in the tary companions to the stars HD 93083, HD 101930 and search for extrasolar planets, allowing the detection of com- HD 102117. Interesting characteristics of these planets include panions of a few Earth masses around solar-type stars. Indeed, a mass in the Saturn-mass regime and below, and an orbital dis- the increase of the planet frequency towards very low masses is tance to the star of 0.1–0.5 AU. According to recent planet for- confirmed by the recent discovery of Neptune-mass exoplanets mation scenarios (Ida & Lin 2004), they are situated in a region (McArthur et al. 2004; Santos et al. 2004a; Butler et al. 2004). of the mass-period diagram that seems difficult to populate. Moreover, the combination of CORALIE (Queloz et al. 2000) The systematic exploration of this mass and distance regime is and HARPS data, extending over several years, will allow the therefore an important test for the core-accretion and migration Based on observations made with the HARPS instrument on theories of planet formation. the ESO 3.6 m telescope at La Silla Observatory under programme This paper is structured as follows. Section 2 describes ID 072.C-0488(E). the observations, the data reduction process and discusses the Article published by EDP Sciences and available at http://www.edpsciences.org/aa or http://dx.doi.org/10.1051/0004-6361:20052864 1122 C. Lovis et al.: The HARPS search for southern extra-solar planets. III. long-term precision of the HARPS measurements. The physi- cal properties of the parent stars are presented in Sect. 3, fol- lowed by the RV measurements and orbital solutions in Sect. 4. We discuss in the last section the characteristics of these new planets in the context of the already-known properties of exo- planets and highlight some theoretical questions that might be answered by radial-velocity surveys in the near future. 2. Observations and measurement precision HD 93083, HD 101930 and HD 102117 are all members of the HARPS high-precision RV sample. The aim of this sur- veyistoobtainRV measurements with photon errors below 1ms−1 to detect very low-mass extrasolar planets. The stars in this sample have been selected from the CORALIE planet Fig. 1. Radial velocities for a sample of 12 stable stars from the HARPS high-precision programme, observed over about 700 days. search database for being non-evolved, having low projected −1 For each star, the mean RV has been subtracted. The overall rms of rotational velocity (v sin i < 3kms ) and exhibiting low ac- −1 ff 1.81 m s is made of di erent contributions, among which photon − − − tivity levels (log RHK < 4.7). These criteria should elimi- noise (∼0.8 m s 1), calibration noise (∼0.8 m s 1), guiding errors nate most stars showing large intrinsic RV variations and select (0.2–0.6 m s−1) and stellar acoustic modes (0.5–2.0 m s−1). Seasonal only very quiet, chromospherically inactive stars, so that stel- averages have been computed (bottom part). The absence of long-term lar RV jitter does not hide possible planetary signals down to drifts and the dispersion of only 0.64 m s−1 illustrate the long-term sta- 1–2 m s−1. Obviously, the photon noise error on the radial ve- bility of ThAr reference lamps. locity must also remain below 1 m s−1. For each HARPS spec- trum we compute the photon-limited, ultimate RV precision us- – The mean photon error, computed according to Bouchy ing the formulae given by Connes (1985) and Bouchy et al. −1 −1 et al. (2001), is 0.8 m s ; (2001). HARPS typically delivers 0.5–1 m s photon-limited – the zero-point wavelength calibration, given by nightly / ∼ −1 accuracy at a S N ratio of 100 per pixel (0.8 km s ) at 550 nm ThAr reference spectra, is presently determined with an ac- on solar-type stars. The exact number mainly depends on the curacy of ∼0.8 m s−1; depth of absorption lines and the projected rotational velocity. – guiding errors are responsible for 0.2–0.6 m s−1 of extra The radial velocities for HD 93083, HD 101930 and dispersion, due to the non-optimal tuning of the guiding HD 102117 have been obtained with the standard HARPS re- software. This issue has now been solved and the guiding duction pipeline, based on the cross-correlation with a stellar noise should remain below 0.3 m s−1 in the future; template, the precise nightly wavelength calibration with ThAr – the largest contribution to the global RV dispersion spectra and the tracking of instrumental drifts with the simul- comes from the star itself, mainly due to acoustic modes taneous ThAr technique (Baranne et al. 1996). Of particular (p-modes). For our 12 stars we estimate this contribution interest is the fact that the nightly instrumental drifts always to be 0.5–2.0 m s−1, depending on spectral type and evolu- −1 remain below 1 m s for HARPS due to the high instrumental tionary status (see Mayor et al. 2003; Bouchy et al. 2005). stability. The observational strategy has been recently optimized to To assess the long-term precision of the instrument, we se- minimize these stellar oscillations, essentially by integrat- lected a sample of 12 stable stars, which have been followed ing over long enough periods to cover more than 1–2 oscil- regularly over the past two years. These stars include HD 55 lations (3–15 min, depending on spectral type). (K5V, V = 8.49), HD 1581 (F9V, V = 4.23), HD 6673 (K1V, V = 8.84), HD 20794 (G8V, V = 4.26), HD 28471 (G5V, Adding all these effects quadratically, we obtain a total dis- V = 7.89), HD 30278 (G8V, V = 7.61), HD 44594 (G4V, persion that is very close to the measured value of 1.81 m s−1 V = 6.61), HD 82342 (K3/K4V, V = 8.31), HD 114853 (the exact number depending on the adopted mean value for (G2V, V = 6.93), HD 162396 (F8V, V = 6.19), HD 196761 the oscillation noise). This leaves only little space (probably (G8/K0V, V = 6.36) and HD 215152 (K0V, V = 8.11).
Load more

Recommended publications
  • Arxiv:1809.07342V1 [Astro-Ph.SR] 19 Sep 2018
    Draft version September 21, 2018 Preprint typeset using LATEX style emulateapj v. 11/10/09 FAR-ULTRAVIOLET ACTIVITY LEVELS OF F, G, K, AND M DWARF EXOPLANET HOST STARS* Kevin France1, Nicole Arulanantham1, Luca Fossati2, Antonino F. Lanza3, R. O. Parke Loyd4, Seth Redfield5, P. Christian Schneider6 Draft version September 21, 2018 ABSTRACT We present a survey of far-ultraviolet (FUV; 1150 { 1450 A)˚ emission line spectra from 71 planet- hosting and 33 non-planet-hosting F, G, K, and M dwarfs with the goals of characterizing their range of FUV activity levels, calibrating the FUV activity level to the 90 { 360 A˚ extreme-ultraviolet (EUV) stellar flux, and investigating the potential for FUV emission lines to probe star-planet interactions (SPIs). We build this emission line sample from a combination of new and archival observations with the Hubble Space Telescope-COS and -STIS instruments, targeting the chromospheric and transition region emission lines of Si III,N V,C II, and Si IV. We find that the exoplanet host stars, on average, display factors of 5 { 10 lower UV activity levels compared with the non-planet hosting sample; this is explained by a combination of observational and astrophysical biases in the selection of stars for radial-velocity planet searches. We demonstrate that UV activity-rotation relation in the full F { M star sample is characterized by a power-law decline (with index α ≈ −1.1), starting at rotation periods & 3.5 days. Using N V or Si IV spectra and a knowledge of the star's bolometric flux, we present a new analytic relationship to estimate the intrinsic stellar EUV irradiance in the 90 { 360 A˚ band with an accuracy of roughly a factor of ≈ 2.
    [Show full text]
  • Li Abundances in F Stars: Planets, Rotation, and Galactic Evolution,
    A&A 576, A69 (2015) Astronomy DOI: 10.1051/0004-6361/201425433 & c ESO 2015 Astrophysics Li abundances in F stars: planets, rotation, and Galactic evolution, E. Delgado Mena1,2, S. Bertrán de Lis3,4, V. Zh. Adibekyan1,2,S.G.Sousa1,2,P.Figueira1,2, A. Mortier6, J. I. González Hernández3,4,M.Tsantaki1,2,3, G. Israelian3,4, and N. C. Santos1,2,5 1 Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [email protected] 2 Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal 3 Instituto de Astrofísica de Canarias, C/via Lactea, s/n, 38200 La Laguna, Tenerife, Spain 4 Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain 5 Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Portugal 6 SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, UK Received 28 November 2014 / Accepted 14 December 2014 ABSTRACT Aims. We aim, on the one hand, to study the possible differences of Li abundances between planet hosts and stars without detected planets at effective temperatures hotter than the Sun, and on the other hand, to explore the Li dip and the evolution of Li at high metallicities. Methods. We present lithium abundances for 353 main sequence stars with and without planets in the Teff range 5900–7200 K. We observed 265 stars of our sample with HARPS spectrograph during different planets search programs. We observed the remaining targets with a variety of high-resolution spectrographs.
    [Show full text]
  • A Proxy for Stellar Extreme Ultraviolet Fluxes
    Astronomy & Astrophysics manuscript no. main ©ESO 2020 November 2, 2020 Ca ii H&K stellar activity parameter: a proxy for stellar Extreme Ultraviolet Fluxes A. G. Sreejith1, L. Fossati1, A. Youngblood2, K. France2, and S. Ambily2 1 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria e-mail: [email protected] 2 Laboratory for Atmospheric and Space Physics, University of Colorado, UCB 600, Boulder, CO, 80309, USA Received date / Accepted date ABSTRACT Atmospheric escape is an important factor shaping the exoplanet population and hence drives our understanding of planet formation. Atmospheric escape from giant planets is driven primarily by the stellar X-ray and extreme-ultraviolet (EUV) radiation. Furthermore, EUV and longer wavelength UV radiation power disequilibrium chemistry in the middle and upper atmosphere. Our understanding of atmospheric escape and chemistry, therefore, depends on our knowledge of the stellar UV fluxes. While the far-ultraviolet fluxes can be observed for some stars, most of the EUV range is unobservable due to the lack of a space telescope with EUV capabilities and, for the more distant stars, to interstellar medium absorption. Thus, it becomes essential to have indirect means for inferring EUV fluxes from features observable at other wavelengths. We present here analytic functions for predicting the EUV emission of F-, G-, K-, and M-type ′ stars from the log RHK activity parameter that is commonly obtained from ground-based optical observations of the ′ Ca ii H&K lines. The scaling relations are based on a collection of about 100 nearby stars with published log RHK and EUV flux values, where the latter are either direct measurements or inferences from high-quality far-ultraviolet (FUV) spectra.
    [Show full text]
  • Naming the Extrasolar Planets
    Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named.
    [Show full text]
  • Exoplanet.Eu Catalog Page 1 # Name Mass Star Name
    exoplanet.eu_catalog # name mass star_name star_distance star_mass OGLE-2016-BLG-1469L b 13.6 OGLE-2016-BLG-1469L 4500.0 0.048 11 Com b 19.4 11 Com 110.6 2.7 11 Oph b 21 11 Oph 145.0 0.0162 11 UMi b 10.5 11 UMi 119.5 1.8 14 And b 5.33 14 And 76.4 2.2 14 Her b 4.64 14 Her 18.1 0.9 16 Cyg B b 1.68 16 Cyg B 21.4 1.01 18 Del b 10.3 18 Del 73.1 2.3 1RXS 1609 b 14 1RXS1609 145.0 0.73 1SWASP J1407 b 20 1SWASP J1407 133.0 0.9 24 Sex b 1.99 24 Sex 74.8 1.54 24 Sex c 0.86 24 Sex 74.8 1.54 2M 0103-55 (AB) b 13 2M 0103-55 (AB) 47.2 0.4 2M 0122-24 b 20 2M 0122-24 36.0 0.4 2M 0219-39 b 13.9 2M 0219-39 39.4 0.11 2M 0441+23 b 7.5 2M 0441+23 140.0 0.02 2M 0746+20 b 30 2M 0746+20 12.2 0.12 2M 1207-39 24 2M 1207-39 52.4 0.025 2M 1207-39 b 4 2M 1207-39 52.4 0.025 2M 1938+46 b 1.9 2M 1938+46 0.6 2M 2140+16 b 20 2M 2140+16 25.0 0.08 2M 2206-20 b 30 2M 2206-20 26.7 0.13 2M 2236+4751 b 12.5 2M 2236+4751 63.0 0.6 2M J2126-81 b 13.3 TYC 9486-927-1 24.8 0.4 2MASS J11193254 AB 3.7 2MASS J11193254 AB 2MASS J1450-7841 A 40 2MASS J1450-7841 A 75.0 0.04 2MASS J1450-7841 B 40 2MASS J1450-7841 B 75.0 0.04 2MASS J2250+2325 b 30 2MASS J2250+2325 41.5 30 Ari B b 9.88 30 Ari B 39.4 1.22 38 Vir b 4.51 38 Vir 1.18 4 Uma b 7.1 4 Uma 78.5 1.234 42 Dra b 3.88 42 Dra 97.3 0.98 47 Uma b 2.53 47 Uma 14.0 1.03 47 Uma c 0.54 47 Uma 14.0 1.03 47 Uma d 1.64 47 Uma 14.0 1.03 51 Eri b 9.1 51 Eri 29.4 1.75 51 Peg b 0.47 51 Peg 14.7 1.11 55 Cnc b 0.84 55 Cnc 12.3 0.905 55 Cnc c 0.1784 55 Cnc 12.3 0.905 55 Cnc d 3.86 55 Cnc 12.3 0.905 55 Cnc e 0.02547 55 Cnc 12.3 0.905 55 Cnc f 0.1479 55
    [Show full text]
  • 2016 Publication Year 2021-04-23T14:32:39Z Acceptance in OA@INAF Age Consistency Between Exoplanet Hosts and Field Stars Title B
    Publication Year 2016 Acceptance in OA@INAF 2021-04-23T14:32:39Z Title Age consistency between exoplanet hosts and field stars Authors Bonfanti, A.; Ortolani, S.; NASCIMBENI, VALERIO DOI 10.1051/0004-6361/201527297 Handle http://hdl.handle.net/20.500.12386/30887 Journal ASTRONOMY & ASTROPHYSICS Number 585 A&A 585, A5 (2016) Astronomy DOI: 10.1051/0004-6361/201527297 & c ESO 2015 Astrophysics Age consistency between exoplanet hosts and field stars A. Bonfanti1;2, S. Ortolani1;2, and V. Nascimbeni2 1 Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy e-mail: [email protected] 2 Osservatorio Astronomico di Padova, INAF, Vicolo dell’Osservatorio 5, 35122 Padova, Italy Received 2 September 2015 / Accepted 3 November 2015 ABSTRACT Context. Transiting planets around stars are discovered mostly through photometric surveys. Unlike radial velocity surveys, photo- metric surveys do not tend to target slow rotators, inactive or metal-rich stars. Nevertheless, we suspect that observational biases could also impact transiting-planet hosts. Aims. This paper aims to evaluate how selection effects reflect on the evolutionary stage of both a limited sample of transiting-planet host stars (TPH) and a wider sample of planet-hosting stars detected through radial velocity analysis. Then, thanks to uniform deriva- tion of stellar ages, a homogeneous comparison between exoplanet hosts and field star age distributions is developed. Methods. Stellar parameters have been computed through our custom-developed isochrone placement algorithm, according to Padova evolutionary models. The notable aspects of our algorithm include the treatment of element diffusion, activity checks in terms of 0 log RHK and v sin i, and the evaluation of the stellar evolutionary speed in the Hertzsprung-Russel diagram in order to better constrain age.
    [Show full text]
  • The HARPS Search for Southern Extra-Solar Planets
    The HARPS search for southern extra-solar planets. III. Three Saturn-mass planets around HD 93083, HD 101930 and HD 102117 C. Lovis, M. Mayor, François Bouchy, F. Pepe, D. Queloz, N. C. Santos, S. Udry, W. Benz, Jean-Loup Bertaux, C. Mordasini, et al. To cite this version: C. Lovis, M. Mayor, François Bouchy, F. Pepe, D. Queloz, et al.. The HARPS search for southern extra-solar planets. III. Three Saturn-mass planets around HD 93083, HD 101930 and HD 102117. Astronomy and Astrophysics - A&A, EDP Sciences, 2005, 437 (3), pp.1121-1126. 10.1051/0004- 6361:20052864. hal-00017981 HAL Id: hal-00017981 https://hal.archives-ouvertes.fr/hal-00017981 Submitted on 17 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A&A 437, 1121–1126 (2005) Astronomy DOI: 10.1051/0004-6361:20052864 & c ESO 2005 Astrophysics The HARPS search for southern extra-solar planets III. Three Saturn-mass planets around HD 93083, HD 101930 and HD 102117 C. Lovis1, M. Mayor1, F. Bouchy2,F.Pepe1,D.Queloz1,N.C.Santos3,1, S. Udry1,W.Benz4, J.-L. Bertaux5, C.
    [Show full text]
  • IAU Division C Working Group on Star Names 2019 Annual Report
    IAU Division C Working Group on Star Names 2019 Annual Report Eric Mamajek (chair, USA) WG Members: Juan Antonio Belmote Avilés (Spain), Sze-leung Cheung (Thailand), Beatriz García (Argentina), Steven Gullberg (USA), Duane Hamacher (Australia), Susanne M. Hoffmann (Germany), Alejandro López (Argentina), Javier Mejuto (Honduras), Thierry Montmerle (France), Jay Pasachoff (USA), Ian Ridpath (UK), Clive Ruggles (UK), B.S. Shylaja (India), Robert van Gent (Netherlands), Hitoshi Yamaoka (Japan) WG Associates: Danielle Adams (USA), Yunli Shi (China), Doris Vickers (Austria) WGSN Website: https://www.iau.org/science/scientific_bodies/working_groups/280/ ​ WGSN Email: [email protected] ​ The Working Group on Star Names (WGSN) consists of an international group of astronomers with expertise in stellar astronomy, astronomical history, and cultural astronomy who research and catalog proper names for stars for use by the international astronomical community, and also to aid the recognition and preservation of intangible astronomical heritage. The Terms of Reference and membership for WG Star Names (WGSN) are provided at the IAU website: https://www.iau.org/science/scientific_bodies/working_groups/280/. ​ ​ ​ WGSN was re-proposed to Division C and was approved in April 2019 as a functional WG whose scope extends beyond the normal 3-year cycle of IAU working groups. The WGSN was specifically called out on p. 22 of IAU Strategic Plan 2020-2030: “The IAU serves as the ​ internationally recognised authority for assigning designations to celestial bodies and their surface features. To do so, the IAU has a number of Working Groups on various topics, most notably on the nomenclature of small bodies in the Solar System and planetary systems under Division F and on Star Names under Division C.” WGSN continues its long term activity of researching cultural astronomy literature for star names, and researching etymologies with the goal of adding this information to the WGSN’s online materials.
    [Show full text]
  • Mètodes De Detecció I Anàlisi D'exoplanetes
    MÈTODES DE DETECCIÓ I ANÀLISI D’EXOPLANETES Rubén Soussé Villa 2n de Batxillerat Tutora: Dolors Romero IES XXV Olimpíada 13/1/2011 Mètodes de detecció i anàlisi d’exoplanetes . Índex - Introducció ............................................................................................. 5 [ Marc Teòric ] 1. L’Univers ............................................................................................... 6 1.1 Les estrelles .................................................................................. 6 1.1.1 Vida de les estrelles .............................................................. 7 1.1.2 Classes espectrals .................................................................9 1.1.3 Magnitud ........................................................................... 9 1.2 Sistemes planetaris: El Sistema Solar .............................................. 10 1.2.1 Formació ......................................................................... 11 1.2.2 Planetes .......................................................................... 13 2. Planetes extrasolars ............................................................................ 19 2.1 Denominació .............................................................................. 19 2.2 Història dels exoplanetes .............................................................. 20 2.3 Mètodes per detectar-los i saber-ne les característiques ..................... 26 2.3.1 Oscil·lació Doppler ........................................................... 27 2.3.2 Trànsits
    [Show full text]
  • Frequency of Debris Disks Around Solar-Type Stars: First Results from a Spitzer Mips Survey G
    The Astrophysical Journal, 636:1098–1113, 2006 January 10 A # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. FREQUENCY OF DEBRIS DISKS AROUND SOLAR-TYPE STARS: FIRST RESULTS FROM A SPITZER MIPS SURVEY G. Bryden,1 C. A. Beichman,2 D. E. Trilling,3 G. H. Rieke,3 E. K. Holmes,1,4 S. M. Lawler,1 K. R. Stapelfeldt,1 M. W. Werner,1 T. N. Gautier,1 M. Blaylock,3 K. D. Gordon,3 J. A. Stansberry,3 and K. Y. L. Su3 Received 2005 August 1; accepted 2005 September 12 ABSTRACT We have searched for infrared excesses around a well-defined sample of 69 FGK main-sequence field stars. These stars were selected without regard to their age, metallicity, or any previous detection of IR excess; they have a median age of 4 Gyr. We have detected 70 m excesses around seven stars at the 3 confidence level. This extra emission is produced by cool material (<100 K) located beyond 10 AU, well outside the ‘‘habitable zones’’ of these systems and consistent with the presence of Kuiper Belt analogs with 100 times more emitting surface area than in our own planetary system. Only one star, HD 69830, shows excess emission at 24 m, corresponding to dust with temper- À3 atures k300 K located inside of 1 AU. While debris disks with Ldust /L? 10 are rare around old FGK stars, we find À4 À5 that the disk frequency increases from 2% Æ 2% for Ldust /L? 10 to 12% Æ 5% for Ldust /L? 10 .
    [Show full text]
  • Estimation of the XUV Radiation Onto Close Planets and Their Evaporation⋆
    A&A 532, A6 (2011) Astronomy DOI: 10.1051/0004-6361/201116594 & c ESO 2011 Astrophysics Estimation of the XUV radiation onto close planets and their evaporation J. Sanz-Forcada1, G. Micela2,I.Ribas3,A.M.T.Pollock4, C. Eiroa5, A. Velasco1,6,E.Solano1,6, and D. García-Álvarez7,8 1 Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESAC Campus, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain e-mail: [email protected] 2 INAF – Osservatorio Astronomico di Palermo G. S. Vaiana, Piazza del Parlamento, 1, 90134, Palermo, Italy 3 Institut de Ciènces de l’Espai (CSIC-IEEC), Campus UAB, Fac. de Ciències, Torre C5-parell-2a planta, 08193 Bellaterra, Spain 4 XMM-Newton SOC, European Space Agency, ESAC, Apartado 78, 28691 Villanueva de la Cañada, Madrid, Spain 5 Dpto. de Física Teórica, C-XI, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain 6 Spanish Virtual Observatory, Centro de Astrobiología (CSIC-INTA), ESAC Campus, Madrid, Spain 7 Instituto de Astrofísica de Canarias, 38205 La Laguna, Spain 8 Grantecan CALP, 38712 Breña Baja, La Palma, Spain Received 27 January 2011 / Accepted 1 May 2011 ABSTRACT Context. The current distribution of planet mass vs. incident stellar X-ray flux supports the idea that photoevaporation of the atmo- sphere may take place in close-in planets. Integrated effects have to be accounted for. A proper calculation of the mass loss rate through photoevaporation requires the estimation of the total irradiation from the whole XUV (X-rays and extreme ultraviolet, EUV) range. Aims. The purpose of this paper is to extend the analysis of the photoevaporation in planetary atmospheres from the accessible X-rays to the mostly unobserved EUV range by using the coronal models of stars to calculate the EUV contribution to the stellar spectra.
    [Show full text]
  • Exoplanet.Eu Catalog Page 1 Star Distance Star Name Star Mass
    exoplanet.eu_catalog star_distance star_name star_mass Planet name mass 1.3 Proxima Centauri 0.120 Proxima Cen b 0.004 1.3 alpha Cen B 0.934 alf Cen B b 0.004 2.3 WISE 0855-0714 WISE 0855-0714 6.000 2.6 Lalande 21185 0.460 Lalande 21185 b 0.012 3.2 eps Eridani 0.830 eps Eridani b 3.090 3.4 Ross 128 0.168 Ross 128 b 0.004 3.6 GJ 15 A 0.375 GJ 15 A b 0.017 3.6 YZ Cet 0.130 YZ Cet d 0.004 3.6 YZ Cet 0.130 YZ Cet c 0.003 3.6 YZ Cet 0.130 YZ Cet b 0.002 3.6 eps Ind A 0.762 eps Ind A b 2.710 3.7 tau Cet 0.783 tau Cet e 0.012 3.7 tau Cet 0.783 tau Cet f 0.012 3.7 tau Cet 0.783 tau Cet h 0.006 3.7 tau Cet 0.783 tau Cet g 0.006 3.8 GJ 273 0.290 GJ 273 b 0.009 3.8 GJ 273 0.290 GJ 273 c 0.004 3.9 Kapteyn's 0.281 Kapteyn's c 0.022 3.9 Kapteyn's 0.281 Kapteyn's b 0.015 4.3 Wolf 1061 0.250 Wolf 1061 d 0.024 4.3 Wolf 1061 0.250 Wolf 1061 c 0.011 4.3 Wolf 1061 0.250 Wolf 1061 b 0.006 4.5 GJ 687 0.413 GJ 687 b 0.058 4.5 GJ 674 0.350 GJ 674 b 0.040 4.7 GJ 876 0.334 GJ 876 b 1.938 4.7 GJ 876 0.334 GJ 876 c 0.856 4.7 GJ 876 0.334 GJ 876 e 0.045 4.7 GJ 876 0.334 GJ 876 d 0.022 4.9 GJ 832 0.450 GJ 832 b 0.689 4.9 GJ 832 0.450 GJ 832 c 0.016 5.9 GJ 570 ABC 0.802 GJ 570 D 42.500 6.0 SIMP0136+0933 SIMP0136+0933 12.700 6.1 HD 20794 0.813 HD 20794 e 0.015 6.1 HD 20794 0.813 HD 20794 d 0.011 6.1 HD 20794 0.813 HD 20794 b 0.009 6.2 GJ 581 0.310 GJ 581 b 0.050 6.2 GJ 581 0.310 GJ 581 c 0.017 6.2 GJ 581 0.310 GJ 581 e 0.006 6.5 GJ 625 0.300 GJ 625 b 0.010 6.6 HD 219134 HD 219134 h 0.280 6.6 HD 219134 HD 219134 e 0.200 6.6 HD 219134 HD 219134 d 0.067 6.6 HD 219134 HD
    [Show full text]