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Special Notice #366: Symbiotic variable AS 270 brightening

July 24, 2013: AAVSO observer Steve O'Connor (OCN; St. George's, Bermuda) reports a possible brightening episode of the symbiotic variable AS 270.  O'Connor reports the star at V=12.75+/- 0.02 on 2013 July 24.535 (JD 2456498.035). The most recent prior observation reported to the AAVSO International Database (M. Linnolt, LMK; Ocean View, Hawaii, United States) had AS 270 at m(vis)=14.1 on 2013 July 13.390 (JD 2456486.890), suggesting a rise of more than one magnitude in less than two weeks. Nightly monitoring of this star is strongly encouraged during the current episode to determine whether an outburst is in progress.

O'Connor notes the last major outburst of this star occurred in August 2001, and reached visual magnitude 10.8 (P. Nelson, NLX; Ellinbank, Victoria, Australia) on 2001 September 10.5167 (JD 2452163.0167). Observations reported to the AAVSO show AS 270 was brighter than V=13 for 39 days.

AS 270 is well placed in Sagittarius for observers south of 30 degrees North latitude. A Henden (USNO) sequence exists for this star. Both visual and CCD observations are encouraged, CCD photometry in the V band and transformed multicolor photometry (especially in Johnson B).

AS 270 is located at the following (J2000) coordinates: R.A. 18 05 33.73   Dec. -20 20 38.1

Charts may be created using the AAVSO Variable Star Plotter (

Please report observations as soon as possible to the AAVSO International Database using the name AS 270.

This AAVSO Special Notice was compiled by Matthew R. Templeton and Elizabeth O. Waagen.



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