100y Search for Large Amplitude Variables in DASCH Scans Near M44

Details 100y Search for Large Amplitude Variables in DASCH Scans Near M44 100y Search for Large Amplitude Variables in DASCH Scans Near M44

Jan 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21342707t&link_type=abstract

American Astronomical Society, AAS Meeting #213, #427.07; Bulletin of the American Astronomical Society, Vol. 41, p.259

Other

1

Scientific paper

Astronomical source variability is poorly explored on 1-100y timescales, where large scale systematic surveys are generally lacking. The Digital Access to a Sky Century at Harvard (DASCH) Collaboration has developed an ultra-high speed digital plate scanner which will ultimately enable the digitizing of the 500,000 Harvard plates from the 1880s to the 1980s with limiting magnitudes ranging from B=14-19. Every point on the sky has been observed typically 300-1000 times with typical error 0.1 mag. For several science demonstration projects, we have scanned more than 3000 plates in several different fields. Here we present our search for large amplitude variables (> 1 mag) over 600 plates which covered a 20deg x 20deg field (with radially decreasing coverage) centered on the open cluster M44. Preliminary detection rate of known variables in this field is 30% , but expected to improve when over-rejection and other issues are optimized. Among the new variables we found there are 77 RR Lyr, Mira, Pulsating stars, DNe or irregular variable candidates, 116 eclipsing binaries (most of them are Algol systems), 37 flare stars, 5 red R Coronae Borealis (RCB) candidates, and most interestingly, 3 very unusual variables that do not match any of the common classes and might be captured during extremely short-lived stellar evolutionary stages: one blue variable with a 1 mag flare on a 10y timescale, one red variable with unusual long-term variability which became 1 mag fainter in 90y, one 'mini-FU Orionis' red variables with a 1.5 mag flare with decay time 8y and otherwise constant for decades before and after the flare. Based on the fairly well defined sample of different classes found in the search, we also estimate the likely event rate for each class.

Affiliated with

Also associated with

No associations

Rating

100y Search for Large Amplitude Variables in DASCH Scans Near M44 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 100y Search for Large Amplitude Variables in DASCH Scans Near M44, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 100y Search for Large Amplitude Variables in DASCH Scans Near M44 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1703140