Notes for PSR B1620-26

update: 29 June 1999

The planet:

• Detection method: Timing
• Basic data: The fit of the timing curve gives several solutions for the planet (Thorsett et al. 1999):

  Parameter	solution 1		solution 2		solution 3
  M.sini ( MJ):	1.2		3.4		6.7	(7.0 (Ford et al. 1999))
  Semi-major axis (AU):	~ 10		30		64	(60 (Ford et al. 1999))
  Orbital period (yrs):	61.8		129		389	( ~ 300 (Ford et al. 1999))
  Eccentricity:	0.		0.2		0.5	(0.45 (Ford et al. 1999))

• Remarks: The pulsar is in a binary system (period = 191.4428 d.) with a white dwarf companion (Thorsett et al. 1999); this explains the uncertainties in the fitting of the planet parameters.
• References:
  1. ARZOUMIAN Z., JOSHI K., RASIO F. & THORSETT S., 1996
     Orbital Parameters of the PSR B1620-26 Triple System.
     in Pulsars: Problems and Progress,
     eds. M. Bailes, S. Johnston, & M. Walker
     (IAU Colloquium 160, Astronomical Soc. of the Pacific, Conf. Series), p.525.
     paper
  2. BACKER D. C., FOSTER R. S. & SALLMEN S., 1993
     A second companion of the millisecond pulsar 1620-26
     Nature, 365, 817
  3. FORD E., JOSHI K., RASIO F. & ZBARSKI B., 1999
     Theoretical Implications of the PSR B1620-26 Triple System and its Planet
     ApJ., 528, 336
     paper preprint
  4. JOSHI K. & RASIO F., 1997
     Distant Companions and Planets around Millisecond Pulsars
     ApJ., 479, 948
     paper
     (ApJ., 488, 901: erratum)
  5. RASIO F., 1998
     New Evidence for a Planet or Brown Dwarf in Orbit Around PSR B1620-26.
     in Proc. of Texas Symposium on Relativistic Astrophysics, eds. A. Olinto et al. (Ann. N.Y. Acad. Sci.), in press.
  6. RASIO F. A., 1994
     Is there a planet in the PSR 1620-26 triple system?
     ApJ. Letters, 427, 107L
     abstract and paper.
  7. SCHEARER A., BUTLER R., REDFERN R., CULLUM M.; & DANKS A., 1996
     A Search for the Optical Counterpart of the Triple Pulsar System PSR B1620-26 in M4.
     ApJ.L., 473, L115
     paper
  8. SIGURDSSON S., 1995
     Assessing the Environmental Impact on PSR~B1620-26 in M4.
     ApJ., 452, 323 abstract
  9. THORSETT S., ARZOUMANIAN Z., CAMILO F. & LYNE A., 1999
     The Triple Pulsar System PSR B1620-26 in M4
     ApJ. 523, 763
     paper

The star:

• Distance: 3.8 kpc
  This distance is deduced from a DM of 63 pc.cm^-3, using the on-line model of Taylor and Cordes (ApJ., 411, 674, 1993).

• Coordinates (2000): RAB = 16:20:34.17510, DECB = -26:-24:-58.56000

• More data:
  • Basic Data (from the Princeton Pulsar Group; enter `1620-26' in the `pulsar catalog information' field).
  • Most recent refs. (from ADS; enter `PSR 1620-26' in the `objects' field)