Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream

Details Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream

Aug 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006iaujd..13e..23f&link_type=abstract

Exploiting Large Surveys for Galactic Astronomy, 26th meeting of the IAU, Joint Discussion 13, 22-23 August 2006, Prague, Czech

Astronomy and Astrophysics

Astronomy

Scientific paper

Introduction: We ask whether the Hyades stream is primarily composed of coeval stars originating from the on-going evaporation of the Hyades cluster, or of field stars trapped at resonance by spiral perturbation. Methods: Using the Geneva-Copenhagen survey of F and G dwarfs (Nordström et al. 2004), we compare the mass distribution of the stream to the mass distribution of field disk stars. Results: The mass distribution of the stream does not obey the initial mass function expected for an evaporated cluster. We show that, for low-mass stars (m < 1 M_sun), the stream is primarily composed of field stars, most probably originating from the inner Galaxy. Discussion: Series of strong transient spirals with their mean corotation at the solar galactocentric radius are known to produce small-scale structure in the local velocity distribution. Stars on horseshoe orbits that cross the corotation could wander over 2-3 kpc in much less than 1 Gyr, while staying on quasi-circular orbits, not elongated enough to betray their place of birth. This would be consistent with a galactocentric origin near R=6 kpc for the Hyades stream, that could explain its metallicity excess at low masses. On the other hand, the Hyades stream could also correspond to nearly closed orbits trapped at the 4:1 inner Lindblad resonance of a two-armed spiral density wave. In any case, the prominence of the Hyades dynamical stream raises the question of the amplitude of the spiral perturbation needed to produce such a stream. A large amplitude would probably also be needed to produce the large non-axisymmetric motion of the star-forming region W3OH. This would require the baryonic disk to be massive even near the sun, and could be very constraining for the dark matter distribution in the Galaxy (see e.g. Famaey & Binney 2005).

Affiliated with

Also associated with

No associations

Rating

Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream 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 Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Using The Geneva-Copenhagen Survey To Study The Nature Of The Hyades Stream will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1624381