Welcome to the AAPS
  1. 7 Feb 2007 - AAPS announces three new planets orbiting G-dwarfs

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.
How our planet search works.
  1. Every planets exert a small gravitational pull on its parent star, causing the star to wobble. In particular, its velocity will be continually varying as it repeatedly moves away from, and then back towards, the Earth. Such velocity changes can be detected via the Doppler Effect.
  3. When the unseen planet is moving away from the Earth, the star will move 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 is moving toward the Earth - the star moves away, and the light it emits is shifted to longer (redder) wavelengths.
  5. The velocity changes revealed by this Doppler wobble depend on the distance at which the planet orbits, the mass of the planet, and how circular its orbit is. For typical gas-giant planets the Doppler velocity variations are in the range 1 to 100 m/s. 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 UCLES spectrograph on the AAT.
  1. So stars with planets can be identified via the observation of periodic Doppler shifts in their 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 1 meter per second (a slow 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 AAPS Project
  2. AAPS has been operating since January 1998, and is expected to run until at least 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 around 240 of the nearest and brightest Sun-like stars visible from the AAT's Southern Hemisphere location on 32 nights per year. (In addition we are also carrying out intensive campaign-mode observations on 48 nights per year, of smaller sets of the most stable stars in our main sample, in an effort to find small planets of masses down to a few times the mass of the Earth).
  4. 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 (like that shown above). 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.
  6. 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?
Team Members & Contact Details (in alphabetical order)
  1. Jeremy Bailey, Macquarie University (jbailey -at- els.mq.edu.au)
  2. Brad Carter, University of Southern Queensland (carterb - at- usq.edu.au)
  3. James Jenkins, University of Hertfordshire (j.s.jenkins -at- herts.ac.uk)
  4. Hugh Jones, University of Hertfordshire (h.r.a.jones -at- herts.ac.uk)
  5. Geoff Marcy, University of California, Berkeley (gmarcy -at- etoile.Berkeley.edu)
  6. Simon O'Toole, Anglo-Australian Observatory (otoole -at- aao.gov.au)
  7. Chris Tinney, University of New South Wales (cgt -at- phys.unsw.edu.au)
Contact Information
  1. AAT Control Room +61 48 42 6279
  2. AAT FAX +61 68 84 2298
  3. AAT Co-ordinates
  4. Geodetic coordinates:
  5.     Longitude = 149:03:57.91 = 9h56m15.861 East
  6.     Lattitude = 31:16:37.34 South
  7.     Altitude = 1164 m
AAPS Publications
  1. Planet Detection Papers
  3. 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
  4. II - Two New Planets from the Anglo-Australian Planet Search. 
    Butler et al. 2001, ApJ, 555, 410.
    ADS Abstract and Links
  5. III -Two Extrasolar Planets from the Anglo-Australian Planet Search
    Tinney et al. 2002, ApJ, 571, 528.
     ADS Abstract and Links
  6. 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
  7. V -On the Double Planet System Around HD 83443
    Butler et al. 2002, ApJ, 578, 565.
    ADS Abstract and Links
  8. VI - Extra-solar planets around HD 196050, HD 216437 and HD 160691
    Jones et al. 2003, MNRAS, 337, 1170.
    ADS Abstract and links
  9. VII - Four new planets around metal-enriched stars
    Tinney et al. 2003, ApJ, 587, 423.
    ADS Abstract and links
  10. VIII - An exoplanet in orbit around τ1 Gruis
    Jones et al. 2003, MNRAS, 341, 948.
    ADS Abstract and Links
  11. IX - A Planet in a Circular Orbit with a 6 Year Period
    Carter et al. 2003. ApJ, 593, L43.
    ADS Abstract and Links
  12. X - Multiple Companions to HD 154857 & HD 160691
    McCarthy et al. 2004, ApJ, 617, 575.
    ADS Abstract and Links
  13. XI - Three low-mass planets from the Anglo-Australian Planet Search
    Tinney et al. 2005, ApJ, 623, 1171.
    ADS Abstract and Links
  14. XII - High-eccentricity planets from the Anglo-Australian Planet Search
    Jones et al. 2006, MNRAS, 369, 249.
    ADS Abstract and Links
  15. XIII - The 2:1 Resonant Exoplanetary System Orbiting HD 73526
    Tinney et al. 2006, ApJ, 647, 594.
    ADS Abstract and Links
  16. 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
  17. XV - New Planets around Three G Dwarfs
    O'Toole et al. 2007, ApJ, 660, 1636.
    ADS Abstract and Links
  19. Other AAPS papers
  21. 1. Echelle spectroscopy of Ca II HK activity in Southern Hemisphere planet search targets.
    Tinney et al. 2002, MNRAS, 332, 759.
    ADS Abstract and Links
  22. 2. 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
  23. 3. Observed Properties of Exoplanets: Masses, Orbits, and Metallicities
    Marcy et al. et al. 2005, Prog.Ther.Phys, 158, 24.
    ADS Abstract and Links
  24. 4. Catalog of Nearby Exoplanets
    Butler et al. 2006, ApJ, 646, 505.
    ADS Abstract and Links
  25. 5. The abundance distribution of stars with planets
    Bond et al. 2006, MNRAS, 370, 163.
    ADS Abstract and Links
  26. 6. An activity catalogue of southern stars
    Jenkins et al. 2006, ApJ, 372, 163.
    ADS Abstract and Links

  27. Astroseismology Papers using the AAPS Radial Velocity System
  29. 1. Evidence for Solar-like Oscillations in β Hydri
    Bedding et al. 2001, ApJ, 549, L105.
    ADS Abstract and Links

  30. 2. Solar-like oscillations in β Hydri: Confirmation of a stellar origin for the excess power
    Carrier et al. 2001, A&A, 378, 142.
    ADS Abstract and Links.

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

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

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

  34. 6. 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

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

  36. 8. Solar-like oscillations in the metal-poor subgiant ν Indi: II. Acoustic spectrum and mode lifetime
    Carrier et al. 2007, A&A, in press.
    astro-ph preprint

AAPS Planets : New Planets and Past Announcements
  2. 7 Feb 2007 - AAPS announces three new planets orbiting G-type dwarfs
  3. August 2006 - AAPS publishes an exoplanetary system in a 2:1 resonance.
  4. ApJ paper on the HD73526 resonant system.
  5. June 2006 - AAPS publishes two new high eccentricity planets.
  6. MNRAS paper on HD187085 and HD20782 systems
  7. 15 Sep 2004 - AAPS announces five new extra-solar planets!
  8. 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).
  9. 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.
  10. 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.
  11. The published papers are available with data on HD160691 & HD158457 and HD117618, HD102117 & HD208487
  12. 4 July 2003 : detection of the best Solar System analog yet found orbiting HD70642
  16. Upper right - Artists impression of the HD70642 gas giant planet, with hypothetical moons.
    Photo Credit: David A. Hardy, astroart.org (c) PPARC.

  17. Lower left - HD70642 Orbital graphic
  24. 17 Sep 2002 : detection of a Jupiter-mass planet orbiting tau1 Gruis
Photo Credit: David A. Hardy, astroart.org
  1. 8 July 2002 : detection of a sub-Saturn "hot Jupiter"
      planet orbiting HD76700
  2. 26 June 2002: detection of an eccentric gas giant planet orbiting HD2039
  3. 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!  (AAO press release, NASA graphics, UK press release)
  4. Photo Credit: Lynette Cook
  6. 16 October 2001 : the detection of three
    new extra-solar planets  
    AAO press release )

    Photo Credit: David Hardy, astroart.org (c) PPARC
  9. 11 December 2000 :  the detection of three extra-solar planets and a brown dwarf (AAO press release, UK press release)
Page maintained by Chris Tinney. Last updated 9 July 2007.
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.