Notes for 51 Peg

update: 18 September 2001

The planet(s):

Detection method: Radial Velocity
(with the Elodie spectrograph at the Observatoire de Haute Provence)

Basic data:

Name:	51 Peg b
M.sini:	0.44 M_J
Semi-major axis:	0.0512 AU
Orbital period:	4.23 d.
Eccentricity:	0.013
Omega (deg):	31
T_peri (JD-2450000):	68.89
Inclinaison:	-

Remarks:
- The orbital distance to the star (0.05 AU) was incompatible with theoretical predictions (A. Boss, Science, 287, 360, 1995) and has triggered speculations on orbital migration (Lin et al. 1996, Rasio et al., 1996)
- No second companion found (Marcy 1996)
- Further evidence for a planet (Hatzes et al., 1996, 1997): nonradial oscillation modes (l > 4) excluded to explain RV amplitude
- Further evidence for a planet (Pravdo et al., 1996) from X-ray non detection
- Planet or M2 star? This question was implicitely raised by a paper by the PTI team claiming that the 51 Peg system may be resolved. See the comment by G. Marcy
- Circumstellar disk searched for at UKIRT and KECK but not found (Trilling et al. 1999 and 2000)
Data:
- Inclination:
  - Near 90 ^o from Vsini (P. François et al. 1996).
  - < 85 ^o from absence of occultations by the companion (Henry et al. 1997)
  - ~ 0^o if it is an M2 star.
- Radius: 1.2 - 1.4 R_J from models by Guillot et al. (1996) (depending on the mass and thus on the inclination)
- T_eff: 1241 K (from Guillot et al. (1996));
  if the radius of the star is 1.7 R_Sun, then T_eff = 1425 K.
- Epoch: T_o = 2450203.947 +/- 0.03 (from Butler & Marcy 1996)
References:
- BROWN T., KOTAK R., HORNER S., KENELLY E., KORZENNIK S., NISENSON P. & NOYES R., 1997
  A search for line shape and variations in 51 Pegasi and tau Boötis.
  ApJ. Lett., in press
  preprint
- G. BRYDEN & D.N.C. LIN 1996
  Orbital Migration of Giant Protoplanets
  Stony Brook Workshop on Planets in Binary Stars (16-18 June 96)
  ( abstract).
- BUNDY & MARCY G., 2000
  Search For Transit Effects in Spectra of 51 Peg and HD 209458.
  PASP, accepted.
  preprint
- BUTLER P. & MARCY G., 1996
  The Lick Observatory Planet Search
  Submitted to: Astronomical and Biochemical Origins and the Search for Life in the Universe, IAU Colloquium No. 161, Capri 1-5 July 1996, eds. C.B. Cosmovici, S. Bowyer, and D. Werthimer
  preprint
- COUSTENIS A., SCHNEIDER J., WITTEMBERG R., CHASSEFIERE E., GREENE T., PENNY A. & GUILLOT T., 1997
  High-resolution Ground-based Spectroscopy of 51 Peg B: Search for Atmospheric Signatures
  in Brown Dwarfs and Extrasolar Planets (Tenerife 1997) abstract
- COUSTENIS A., SCHNEIDER J., BOCKELEE-MORVAN D., RAUER H., WITTEMBERG R., CHASSEFIERE E., GREENE T., PENNY A. & GUILLOT T., 1996
  Spectroscopy of 51 Peg B: Search for Atmospheric Signatures
  Planets Beyond the Solar System and the Next Generation of Space Missions
  Baltimore 16-18 Octonber 1996
  abstract
- FRANCOIS P.,BRIOT D., SPITE F. & SCHNEIDER J., 1999
  Planets around 51 Peg and ups. And.
  A. & A., 349, 220
  paper
- P.FRANCOIS, M.SPITE, D.GILLET, J.-F.GONZALEZ and F.SPITE, 1996
  Accurate determination of the projected rotational velocity of 51 Pegasi
  Astron. & Astrophys., 310, L13
  abstract.
- GIMENEZ A., 2000
  ubvy Photometry of stars with planets.
  Astron. & Astrophys., 356, 213.
  paper
- GLANZ J., 1997
  Is First Extrasolar Planet a Lost World?
  Science, 275, 1257
  abstract and paper
- GLANZ J., 1997
  51 Peg and the Perils of Planet Searches
  Science, 276, 1338
  abstract and paper
- GOUKENLEUQUE C., BEZARD B., JOGUET B., LELLOUCH E. & FREEDMAN R., 2000
  Radiative equilibrium model of 51 Peg
  Icarus, 143, 308
  paper
- GOUKENLEUQUE C., BEZARD B. & LELLOUCH E., 1998
  Radiative Equilibrium Model of 51 Peg b
  in 30^th DPS Meeting
  abstract
- GRAY D. & HATZES A. 1997
  Non-radial oscillation in the solar-temperature star 51 Pegasi.
  Ap.J. accepted
  preprint
- GRAY D., 1998
  A planetary companion for 51 Pegasi implied by absence of pulsations in the stellar spectra.
  Nature, 391, 153
  abstract
- GRAY D., 1997
  Absence of a planetary signature in the spectra of 51 Pegasi.
  Nature, 385, 795
  abstract
- GUILLOT T., BURROWS A., HUBBARD W. B., LUNINE J. I., SAUMON, D., 1996 Giant Planets at Small Orbital Distances (model of 51 Peg b)
  ApJ. Letters, 459, L35
  (paper)
- HATZES A., COCHRAN W. & BAKKER E., 1998
  Further evidence for the planet around 51 Pegasi
  Nature, 391, 154
  abstract and preprint
- HATZES A., COCHRAN W. & JOHNS-KRULL C., 1996
  A Search for Variability in the Spectral Line Shapes of 51 Peg: Further Evidence for a Planet.
  ApJ. Letters in press
  abstract and preprint
- HENRY G., BALIUNAS S., DONAHUE R., SOON W., & SAAR S., 1997
  Properties of Sun-Like Stars with Planets 51 Pegasi, 47 Ursae Majoris, 70 Virginis, and HD114762
  Apj., 474, 503
  paper
- HORNER S., BROWN T., KENELLY E., NOYES R., JHA S., KORZENNIK S. & NISENSON P., 1997
  51 Pegasi and Tau Bootis: Planets or Pulsations?
  Poster at the Los Alamos Conference on Stellar Pulsation, June 16-20
- KRISCIUNAS K., 1997
  The Discovery of Non-Radial Gravity-mode Pulsations in $\gamma$ Doradus-Type Stars
  Presented at IAU Symposium 185, New Eyes to See Inside the Sun and Stars. Pushing the Limits of Helio- and Asteroseismology with New Observations from Ground and from Space, Kyoto, 18-22 August, 1997
  abstract and preprint
- LIN D. N. C., BODENHEIMER P. & RICHARDSON, D. C, 1996
  Orbital migration of the planetary companion of 51 Pegasi to its present location
  Nature, 380, 606
  paper
- MARCY G., 1998
  Extrasolar Planets
  Nature, 391, 127
  abstract
- MARCY G., BUTLER P., WILLIAMS E., BILDSTEN L. & GRAHAM J., 1996
  The Planet Orbiting 51 Peg
  Astrophys. J. 481, 926
  paper
- MAYOR M. and QUELOZ D., 1995
  A Jupiter-mass companion to a solar-type star
  Nature, 378, 355
- PAN X., SULKARNI S. COLAVITA M. & SHAO M., 1997
  Recent measurements of stars with planets using the Palomar Testbed Interferometer
  in Brown Dwarfs and Extrasolar Planets (Tenerife 1997)
  paper
- PRAVDO S.H., ANGELI L, DRAKE S,, STERN R. & WHITE N., 1996
  The X-ray Evidence that the 51 Peg Companion is a Planet
  New Astronomy, 1, no. 2, November, p. 171
  paper
- F. RASIO, C. TOUT, S. LUBOW and M. LIVIO 1996
  Tidal Decay of Close Planetary Orbits
  ApJ, 470, 1187
  ( preprint).
- RAUER H., BOCKELEE-MORVAN D., COUSTENIS A., GUILLOT T. & SCHNEIDER J., 1999
  Search for an exosphere around 51 Peg with ISO.
  Astron. Astrophys., accepted
- RUZMAIKINA T., 1999
  Formation of 51 Pegasi-Type Systems.
  Icarus submitted
- RUZMAIKINA T., 1996
  Formation of 51 Pegasi-Type Systems
  28^th DPS meeting
  abstract
- RYAN S, 2000
  The Host Stars of Extrasolar Planets Have Normal Lithium Abundances.
  MNRAS, in press preprint
- TAKEDA Y., SATO B., KAMBE E., AOKI W., HONDA S., KAWANOMOTO S., MASUDA S., IZUMIURA H., WATANABE E., KOYANO H., MAEHARA H., NORIMOTO Y., OKADA T., SHIMIZU Y., URAGUCHI F., YANAGIZAWA K. YOSHIDA M., NIYAMA S. & ANDO H., 2001
  Photospheric Abundances of Volatile and Refractory Elements in Planet-Harboring Stars.
  PASJ, in press
  preprint
- TRILLING D., BROWN R. & RIVKIN A., 1999
  Circumstellar dust disks and extrasolar planets: Far-off analogs of our Solar System
  in 31^st Annual Meeting of the DPS
  abstract
- TRILLING D., BROWN R. & RIVKIN A., 2000
  Circumstellar Dust Disks around Stars with Known Planetary Companions.
  ApJ., 529, 499
  paper
- WALKER G., 1997
  One of our planets is missing
  Nature, 385, 775
  abstract
Other Web pages:
1. Geneva Observatory data
2. Velocity curve and data (Butler and Marcy)
3. Precise radial velocity with AFOE (Advanced Fiber Optic Echelle Spectrometer; Sylvain G. Korzennik et al., Harvard)
4. David Gray's comments.
5. photometric monitoring of 51 Peg at Mount Wilson (Henry et al.) versus orbital phase and Julian Date
6. 51 Peg Web page at U. of Oregon.
7. Illustration From Adler Planetarium: Illustration of our solar system compared to 51 Peg and animations.
8. Visualisation of 51 Peg (John Whatmough)
9. Sky chart (Seti League)
10. Vanishing World (Scientific American)

The star:

Distance: 14.7 pc
Spectral type: G2IV
Metallicity: [Fe/H] = 0.06 - 0.19
Apparent magnitude: B = 6.16, V = 5.5
Coordinates (2000): RA = 22 57 27.14, DEC = +20 46 04.5
More data:
- Basic Data (from simbad )
- Most recent refs. (from ADS; enter `51 Peg' in the `objects' field)

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