Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae

Details Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae

Jan 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997apj...474l.119b&link_type=abstract

Astrophysical Journal Letters v.474, p.L119

Astronomy and Astrophysics

Astronomy

68

Stars: Activity, Stars: Planetary Systems, Stars: Late-Type, Techniques: Photometric, Techniques: Spectroscopic

Scientific paper

Planets have been reported orbiting the Sun-like stars rho 1 Cnc, tau Boo, and upsilon And based on low-amplitude radial velocity variations. We have derived information on the first two stars from analysis of spectra, as well as parallel records of high-precision Stromgren b and y photometry and Ca II H + K fluxes. In the case of rho 1 Cnc, the upper limit (peak to peak) of nondetection of photometric variability at the orbital period is Delta y ~ 0.0004 mag. The possibility of a planetary transit cannot be ruled out completely from the photometric data. Variations of the Ca II fluxes suggest a rotational period of ~42 days, in agreement with the inferred v sin i ~ 2 km s-1. The age of rho 1 Cnc is ~5 Gyr, based on its average Ca II flux and a relation between Ca II flux and age. The star tau Boo, unlike the other reported solar-type stars with planets, is relatively young (~2 Gyr). Despite its young age, it is photometrically nonvariable at the orbital period with an amplitude of Delta (b + y)/2 ~ 0.0004 mag (peak to peak); however, small-amplitude interseasonal variability is seen. No planetary transits were found in the photometry, which limits the inclination of the planet's orbital plane to Earth's line of sight to less than 83 deg (where 90 deg is coplanar). The Ca II record shows a weakly significant rotational period near 3.3 days, coincident with the orbital period of the companion. The Ca II record also shows a period of 116 days that has persisted for 30 years and is not seen in the photometric record. The persistence and timescale of this Ca II variation mean that it has no counterpart in Sun-like magnetic activity. The amplitude of the reflex velocity of the parent star (~450 m s-1) is much larger than the radial velocity perturbations expected from the presence of either surface inhomogeneities or line-bisector variations. Thus the anticipated perturbations from those stellar effects do not refute the inference of reflex velocities. We have few Ca II flux measurements for upsilon And. Its age and rotational period are estimated to be ~5 Gyr and 12 days, respectively. Our results for rho 1 Cnc and tau Boo are consistent with the explanation of planets as the cause of the velocity variations.

Affiliated with

Also associated with

No associations

Rating

Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Properties of Sun-like Stars with Planets: rho 1 Cancris, tau Bootis, and upsilon Andromedae will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1785767