Birth and Death of OH/IR Stars

Details Birth and Death of OH/IR Stars Birth and Death of OH/IR Stars

Nov 2001

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001aas...198.7510l&link_type=abstract

American Astronomical Society, 198th AAS Meeting, #75.10; Bulletin of the American Astronomical Society, Vol. 33, p.1177

Statistics

1

Scientific paper

Arecibo observations are making it ever more obvious that most OH/IR stars only have a 1612 MHz emission phase for a few hundred years. Our most recent evidence comes from accumulating statistics on their births and deaths, where we now appear to have three instances of each. The death of an OH/IR star (loss of a detectable 1612 MHz maser) is easily documented, and ours derive from the reobservation of just 250 stars after 10-15 years. IRAS18455+0448 is the best studied. Its strongest 2.1 Jy feature at discovery in 1988, which was its only maser by 1998, is extinct: the final decline was exponential (ApJ 548, L77). Our second case is U Equ, which has faded from ~ 0.5 Jy in 1988 to <6 mJy. Finally IRAS15060+0947, which had 143 & 370 mJy peaks in May 1985, had a peak intensity of 15 mJy in October 2000. As a normal amplitude variation for 1612 MHz masers around a pulsation cycle is a factor of 2-3, this star should soon lose its masers. The birth of an OH/IR star is more difficult to document, as a prior nondetection may have been caused by encountering the star during a low intensity phase of its cycle, or by rfi: we need to read our old mildewed tapes to check. Nevertheless, the number of births presently matches the number of deaths, as is expected for a steady state population. So in addition to V1511 Cyg (BAAS 32, 1571), we have recently found a 250 mJy maser in IRAS18432+1343, and a 100 mJy maser in IRAS18280+0521. These masers are both strong enough that even if they had been a factor of three weaker when first surveyed, they should have been detected during their previous Arecibo search, which were respectively made in May 1987 and May 1988. Engels & Lewis (A&AS 116, 117) detected water masers from both at Effelsberg in 1994.

Affiliated with

Also associated with

No associations

Rating

Birth and Death of OH/IR Stars 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 Birth and Death of OH/IR Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Birth and Death of OH/IR Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1233238