Astronomy With Small Telescopes

Bohdan Paczynski

November 7, 2006

http://arxiv.org/abs/astro-ph/0609161v3

The All Sky Automated Survey (ASAS) is monitoring all sky to about 14 mag with a cadence of about 1 day; it has discovered about 105 variable stars, most of them new. The instrument used for the survey had aperture of 7 cm. A search for planetary transits has lead to the discovery of about a dozen confirmed planets, so called ’hot Jupiters’, providing the information of planetary masses and radii. Most discoveries were done with telescopes with aperture of 10 cm.

We propose a search for optical transients covering all sky with a cadence of 10 -30 minutes and the limit of 12 - 14 mag, with an instant verification of all candidate events. The search will be made with a large number of 10 cm instruments, and the verification will be done with 30 cm instruments.

We also propose a system to be located at the L1 point of the Earth - Sun system to detect ’killer asteroids’. With a limiting magnitude of about 18 mag it could detect 10 m boulders several hours prior to their impact, provide warning against Tunguska-like events, as well as to provide news about spectacular but harmless more modest impacts.

Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

B.S. Gaudi1, D.P. Bennett, A. Udalski, A. Gould,
G.W. Christie, D. Maoz, S. Dong, J. McCormick,
M.K. Szymanski, P.J. Tristram, S. Nikolaev,
B. Paczynski,
M. Kubiak, G. Pietrzynski, I. Soszynski3,
O. Szewczyk, K. Ulaczyk, Ł. Wyrzykowski,
(The OGLE Collaboration) D.L. DePoy, C. Han, S. Kaspi,
C.-U. Lee, F. Mallia, T. Natusch, R.W. Pogge, B.-G. Park,
(The μFUN Collaboration)
F. Abe, I.A. Bond, C.S. Botzler, A. Fukui, J.B. Hearnshaw,
Y. Itow, K. Kamiya, A.V. Korpela, P.M. Kilmartin, W. Lin1,
K. Masuda, Y. Matsubara, M. Motomura, Y. Muraki, S. Nakamura,
T. Okumura, K. Ohnishi, N.J. Rattenbury, T. Sako, To. Saito,
S. Sato, L. Skuljan, D.J. Sullivan, T. Sumi, W.L. Sweatman,
P.C.M. Yock,
(The MOA Collaboration)
M.D. Albrow, A. Allan, J.-P. Beaulieu, M.J. Burgdorf, K.H. Cook,
C. Coutures, M. Dominik, S. Dieters, P. Fouque, J. Greenhill,
K. Horne, I. Steele, Y. Tsapras,
(From the PLANET and RoboNet Collaborations)
B. Chaboyer, A. Crocker, S. Frank, B. Macintosh

March 19, 2008

http://arxiv.org/abs/0802.1920v2


Searches for extrasolar planets have uncovered an astonishing diversity of
planetary systems, yet the frequency of solar system analogs remains unknown.
The gravitational microlensing planet search method is potentially sensitive to
multiple-planet systems containing analogs of all the solar system planets except
Mercury. We report the detection of a multiple-planet system with microlensing.
We identify two planets with masses of  0.71 and  0.27 times
the mass of Jupiter and orbital separations of  2.3 and  4.6 astronomical
units orbiting a primary star of mass  0.50 solar masses at a distance of
 1.5 kiloparsecs. This system resembles a scaled version of our solar system
in that the mass ratio, separation ratio, and equilibrium temperatures of the
planets are similar to those of Jupiter and Saturn. These planets could not
have been detected with other techniques; their discovery from only six confirmed
microlensing planet detections suggests that solar system analogs may
be common.