The Anglo-Australian Planet Search (AAPS) is a long-term program being carried out on the 3.9m Anglo-Australian Telescope (AAT) to search for giant planets around more than 240 nearby Solar-type stars with V<8. We use the "Doppler wobble" technique to search for these otherwise invisible extra-solar planets, and achieve the highest long-term precision demonstrated by any Southern Hemisphere planet search.

The Anglo-Australian Planet Search Team

R. Paul Butler (Carnegie Institution of Washington)
Chris Tinney (University of New South Wales)
Hugh Jones (University of Hertfordshire)
Geoff Marcy (University of California Berkeley)
Brad Carter (University of Southern Queensland)
Simon O'Toole (Anglo-Australian Observatory)
Jeremy Bailey (Macquarie University)

News

  7 Feb 2007 - AAPS announces three new planets

Three new planets are announced orbiting G-type dwarfs. Two of these planets (those orbiting HD159868 and HD23127) have periods of 3-4 years,  minimum (Msini) masses of between 1.5 and 1.7 times that of Jupiter and orbital semi-major axes of 2-2.4 astronomical units.

The third planet is found as a longer-period companion to the star HD154857 (already known to host a planet with an orbital period of just over a year and minimum mass of 1.8 times that of Jupiter). The second planet has an orbital period of over 5 years.

For further details see the accepted paper available on astro-ph.

How our planet search works.

Exoplanets exerts a small gravitational pull on its parent star, causing the star to wobble. The velocity of this wobble depends on the distance at which the planet orbits, and the mass of the planet. For typical giant planets the velocity variation is in the range 1 to 100 m/s.

This motion can be detected via the Doppler Effect. When the unseen planet is moving away from the Earth, the star will move slightly towards the Earth. The light emitted by a star when it is doing this is Doppler shifted to shorter (bluer) wavelengths. The reverse happens when the unseen planet moves towards the Earth - the star moves away, and the light it emits is shifted to longer (redder) wavelengths. Because of the small velocities involved, the effect is subtle  - it doesn't effect the apparent colour of the star, for example. But it can be detected by very high precision astronomical instruments like the University College London Echelle Spectrograph (or UCLES) on the AAT.

 
How an Unseen Planet Moves its Star A star with a Jupiter-mass planet will be revealed by the periodic Doppler shift of its light. After one or two orbital periods the information from the Doppler measurements allows us to calculate the orbit and mass of the unseen planet. Our current measurement precision is 3 meters per second (a brisk walk). For comparison, Jupiter causes the Sun to wobble with a velocity of 12.5 meters per second over a 12 year period. Saturn induces a 2.7 meter per second wobble on the Sun with a 30 year period. The other planets (in particular the terrestrial planets like the Earth, Mars and Venus) are far too small to produce a measureable effect on the Sun.

 

The project

AAPS has been operating since January 1998, and is expected to run until 2010, at which point we will have observed for long enough to detect Jupiter-like planets in Jupiter-like orbits around other stars. We are currently monitoring the 200 nearest and brightest Sun-like stars visible from the AAT's Southern Hemisphere location on 20 nights per year. We perform these observations using the University College London Echelle Spectrograph (UCLES). UCLES enables us to observe almost  the entire visible spectrum in a single observation. Doppler shifts in the stellar spectra are measured with reference to a precision calibrated iodine vapour absorption cell (ike that shown to the left). The absorption that produces the faint purple colour of the iodine gas in this cell, imprints a dense network of narrow lines on our spectra, telling us everything we need to know about UCLES's performance.
The only example of a star with planets that know in much detail is our own Solar System. Ultimately we need to know what fraction of Sun-like stars have Jupiter- and Saturn-mass planets in Jupiter- and Saturn-like orbits. In other words,  what fraction of extra-solar planetary systems are similar to our own?






AAPS Planets : New Planets and Past Announcments

7 Feb 2007 - AAPS announces three new planets orbiting G-type dwarfs

August 2006 - AAPS publishes an exoplanetary system in a 2:1 resonance.

June 2006 - AAPS publishes two new high eccentricity planets

15 Sep 2004 - AAPS announces five new extra-solar planets!

  • Data for
  • HD160691 (mu Ara) system
  • HD158457 system
  • HD117618 system
  • HD102117 system
  • HD208487 system
  • Data on all AAPS Planet Detections
  • ApJ paper on HD160691/158457
  • ApJ paper on HD117618/102117/208487
    		•
    The five new planets include the first multiple planet systems detected by the AAPS, and three low-mass (ie Saturnian- or sub-Saturnian-mass planets).

    The multiple planet systems include two planets detected around the star mu Ara (in the constellation of Ara "The Altar"). The inner planet has an orbital period of 645 days and a minimum mass of 1.7 Jupiter masses. The outer planet has an orbital period of 8.2 years and a minimum mass of  3.1 Jupiter masses. Both planets have quite eccentric (ie non-circular) orbits. These two planets were recently "joined" by a third inner (but very much smaller) planet in a 9 day orbit announced by Santos et al.

    The three low-mass planets have all been detected with orbital periods of between 26 and 129 days, and minimum masses of between 0.16 and 0.4 times that of Jupiter. These low-mass planets are exciting to the Anglo-Australian Planet Search team because they all have small velocity amplitudes - that is the represent the detection of quite small "wobbles" in the parent stars due to these planets. Indeed at just 12 to 18m/s these results obtained from data streams stretching back to 1998, represent exactly the levels of precision that our search needs to attain to detect Solar Systems like our own around other stars via the orbital motion of a Jupiter-like planet in a Jupiter-like 12 year orbit. They give us confidence that in the next 6 years, if there are any "Solar System-like" systems amongst our 240 targets stars, we will find them.


    4 July 2003 : detection of the best Solar System analog yet found orbiting HD70642
  • AAPS Planet Detections 
  • Data for HD70642 System
  • Scientific Paper at astro-ph

  • Press releases :-

    		•
    tHD70642 (c) PPARC. Credit D.Hardy
    Artisis impression of the HD70642 gas giant
    planet, with hypothetical moons.

    Photo Credit: David A. Hardy, astroart.org
    (c) PPARC

    HD70642 Orbit
    HD70642 Orbit graphic

    17 Sep 2002 : detection of a Jupiter-mass planet orbiting tau1 Gruis
  • AAPS Planet Detections
  • Data for tau1 Gruis
  • Scientific Paper at astro-ph

  • Press releases :-
  • PPARC (UK) Press Release Word and  HTML (with high res. graphics)
  • PPARC Press & Graphics Request contact: 
       Julia Maddock +44 1793 442094 julia.maddock@pparc.ac.uk
  • Carnegie Institute (USA) Press Release (Word)
  • Digital Sky Survey image of tau Gruis (Digital Sky Survey © 1994, AURA, Inc. )
    		•
    tau Gruis (c) PPARC
    Photo Credit: David A. Hardy, astroart.org
    (c) PPARC

    8 July 2002 : detection of a sub-Saturn "hot Jupiter"  planet orbiting HD76700

    26 June 2002: detection of an eccentric gas giant planet orbiting HD2039

    13 June 2002: AAPS, Lick and Keck detect 15 New Planets, including Lick discovery of 55 Cnc c : the first Jupiter-like planet in a Jupiter-like orbit!  (press release, NASA graphics, AAPS graphics)

    June 2002 :  detection of four new planets, and improved orbit for a previous planet press materials, release)

    October 2001 : the detection of three new extra-solar planets (press materials, release)

    December 2000 :  the detection of three extra-solar planets and a brown dwarf (press release)
     

    Stay tuned for more planets as they happen - we always have more in the pipeline!

    Planets Found by AAPS

    The AAPS Target List

    Notes of CaHK Observing for AAPS

    Links

    Team Members
    Chris Tinney (Chris Tinney's contact details)
    Paul Butler (paul - at- dtm.ciw.edu)
    Geoff Marcy (gmarcy -at- etoile.Berkeley.edu)
    Hugh Jones (h.r.a.jones -at- herts.ac.uk)
    Brad Carter (carterb - at- usq.edu.au)
    Simon O'Toole (otoole -at- aao.gov.au)
    Jeremy Bailey (jbailey -at- els.mq.edu.au)
    Some Planet Searches
    Lick and Keck Planet Searches - exoplanets.org
    Elodie and Coralie Planet Searches
    General Resources
    Extra-solar Planet Encyclopaedia (France)
    Extra-solar Planet Encyclopaedia (USA Mirror)

    AAPS Publications

    Planet Detection Papers
    I -First Results from the Anglo-Australian Planet Search: A Brown Dwarf Candidate and a  51 Peg-like Planet.
    Tinney et al. 2001, ApJ, 551, 507. ADS Abstract and Links

    II - Two New Planets from the Anglo-Australian Planet Search. 
    Butler et al. 2001, ApJ, 555, 410. ADS Abstract and Links

    III -Two Extrasolar Planets from the Anglo-Australian Planet Search
    Tinney et al. 2002, ApJ, 571, 528. ADS Abstract and Links

    IV -A probable planetary companion to HD 39091 from the Anglo-Australian Planet Search
    Jones et al. 2002, MNRAS, 333, 871. ADS Abstract and Links. astro-ph

    V -On the Double Planet System Around HD 83443
    Butler et al. 2002, ApJ, 578, 565. ADS Abstract and Links

    VI - Extra-solar planets around HD 196050, HD 216437 and HD 160691
    Jones et al. 2003, MNRAS, 337, 1170. ADS Abstract and links.

    VII - Four new planets around metal-enriched stars
    Tinney et al. 2003, ApJ, 587, 423. ADS Abstract and links.

    VIII - An exoplanet in orbit around tau1 Gruis
    Jones et al. 2003, MNRAS, 341, 948. ADS Abstract and Links

    IX - A Planet in a Circular Orbit with a 6 Year Period
    Carter et al. 2003. ApJ, 593, L43. ADS Abstract and Links

    X - Multiple Companions to HD 154857 & HD 160691
    McCarthy et al. 2004, ApJ, 617, 575. ADS Abstract and Links

    XI - Three low-mass planets from the Anglo-Australian Planet Search
    Tinney et al. 2005, ApJ, 623, 1171. ADS Abstract and Links

    XII - High-eccentricity planets from the Anglo-Australian Planet Search
    Jones et al. 2006, MNRAS, 369, 249. ADS Abstract and Links

    XIII - The 2:1 Resonant Exoplanetary System Orbiting HD 73526
    Tinney et al. 2006, ApJ, 647, 594. ADS Abstract and Links

    XIV - Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars.
    Wright et al. ApJ, 2007. 657, 533. ADS Abstract and Links

    XV - New Planets around Three G Dwarfs
    O'Toole et al. 2007, ApJ, in press. astro-ph preprint


    AAPS Related Papers
    • Echelle spectroscopy of Ca II HK activity in Southern Hemisphere planet search targets.
      • Tinney et al. 2002, MNRAS, 332, 759. ADS Abstract and Links

    • Constraining the difference in convective blueshift between the components of alpha Cen with precise radial velocities
      Pourbaix et al. 2002, A&A, 386, 280. ADS Abstract and links.

    • On the Double-Planet System around HD 83443
      Butler et al. ApJ, 578, 565. ADS Abstract and Links
    • Observed Properties of Exoplanets: Masses, Orbits, and Metallicities
      Marcy et al.       et al. Prog.Ther.Phys, 158, 24. ADS Abstract and Links
    • Catalog of Nearby Exoplanets
      Butler et al. ApJ, 646, 505. ADS Abstract and Links

    • The abundance distribution of stars with planets
      Bond       et al. MNRAS, 370, 163. ADS Abstract and Links
    • An activity catalogue of southern stars
      Butler et al. ApJ, 372, 163. ADS Abstract and Links


    Astroseismology Papers using the AAPS Radial Velocity System

    • Evidence for Solar-like Oscillations in beta Hydri
      Bedding et al. 2001, ApJ, 549, L105. ADS Abstract and Links

    • Ultra-High Precision Velocity Measurements of Oscillations in α Centauri A
      Butler, R.P. et al., 2004, ApJ, 600, L75. ADS Abstract and Links.

    • Oscillation frequencies and mode lifetimes in a Centauri A (2004)
      Bedding, T.R. et al.  2004, ApJ, 614, 380. ADS Abstract and Links

    • Solar-like Oscillations in α Centauri B
      Kjeldsen et al. 2005, ApJ, 635, 1281. ADS Abstract and Links

    • Solar-like Oscillations in the Metal-poor Subgiant ν Indi: Constraining the Mass and Age Using Asteroseismology
      Bedding et al. 2006, ApJ, 647, 558. ADS Abstract and Links

    • Solar-like oscillations in the G2 subgiant beta Hydri from dual-site observations
      Bedding et al. 2007, ApJ, in press. astro-ph preprint




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    Modifications to UCLES to permit iodine automation

    Contact Information

    • AAT Control Room +61 48 42 6279
    • AAT FAX +61 68 84 2298
    • AAT Co-ordinates
    • Geodetic coordinates:
    • Longitude = 149:03:57.91 = 9h56m15.861 East
    • Lattitude = 31:16:37.34 South
    • Altitude = 1164 m


    This page currently maintained by Chris Tinney. Page maintaner details.
    Last updated 19 April 2007.