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Matthew Templeton
April 19, 2011 - 12:27pm

SY Muscae is the first of three symbiotic stars we'll highlight over the next few weeks.  SY Mus is a fine southern Z Andromedae variable although we have yet to observe any outbursts of this star.  It does however show the familiar wave-like variation in the light curve. ...

Matthew Templeton
November 6, 2012 - 11:33am

SY Persei is a semiregular variable (SRa subclass) of long period, over 450 days.  It undergoes reasonably regular pulsations, varying between 8.5 and 13.5, but the light curve varies enough from cycle to cycle to put it in the semiregular (rather than Mira) class of variables.  It...

Matthew Templeton
November 13, 2011 - 2:51pm

T Cas is a northern Mira with what appear to be traveling waves in the light curve.  If you look at the maxima over the last several thousand days, you'll see that there appear to be multiple peaks that shift in time from cycle to cycle.  The depth of the minima appear to change...

Matthew Templeton
August 3, 2012 - 11:21am

T Cen is a bright southern RV Tauri variable, ranging from m(vis) of 5.5 to 9th magnitude.  Successive minima are separated by just under 100 days, but since the minima alternate, the true period is about 190 days.  The RV Tauri stars are highly evolved giant stars that vary due to...

Matthew Templeton
October 22, 2010 - 8:51am

T Monocerotis is a bright pulsating variable star belonging to the class of Cepheid variables.  The Cepheids are variables that undergo self-sustaining, spherically symmetric pulsations with periods of days to weeks.  They have long played an important role in astrophysics,...

Matthew Templeton
April 19, 2011 - 9:38am

T Pyxidis is a curious recurrent nova whose long-term behavior is not yet well understood.  Originally observed in 1890 as a nova, it recurred a few times in the early 20th century but its recurrence time seemed to increase.  After the last outburst in 1966, many astronomers expected...

Matthew Templeton
July 18, 2010 - 11:24am

T Ursae Minoris is (or was) a Mira variable, an asymptotic giant branch star pulsating with a period of about 300 days, and an amplitude of about five magnitudes.  In the 1970s, the behavior of T UMi began to change, including a rapidly declining pulsation period, a decreasing amplitude,...

Matthew Templeton
July 18, 2010 - 11:20am

TT Ari is a cataclysmic variable of the VY Sculptoris class.  The VY Scl stars typically remain in a high state like the nova-like variables, and do not show outbursts like those of dwarf novae.  What makes them different from the novalikes is that they occasionally undergo deep...

Matthew Templeton
November 13, 2011 - 2:32pm

TX Cam is a long-period Mira variable with highly variable amplitude.  It's also a known bright IR source and has strong maser emission, both of which come from the mass that's being shed by this rapidly evolving star.  The long-period Miras are interesting objects because...

Matthew Templeton
January 22, 2013 - 2:55pm

TX Persei is an RV Tauri variable of the RVa subclass, meaning it maintains a constant mean brightness without a long secondary period seen in the RVb subclasses.  Like many RV Tauri stars, the light curve shows some evidence of periodicity, with reasonably regular dips in brightness...

SXN
March 22, 2012 - 12:57pm

U Aquarii belongs to the RCB class of stars. R Coronae Borealis stars (RCBs) are a small group of hydrogen poor, carbon rich supergiants that decline in brightness unpredictably and rapidly by up to 9 magnitudes, and remain at or near minimum light for several weeks or months, even years in...

Matthew Templeton
October 21, 2010 - 5:22pm

U Geminorum is the class prototype for the dwarf nova subclass of cataclysmic variables.  Discovered in 1855 by British astronomer J.R. Hind, U Gem has intrigued generations of astronomers, and remains a fascinating (and scientifically useful) target to this day.  U Gem, like all of...

Matthew Templeton
September 10, 2012 - 1:39pm

U Mic is a classic mira variable with a period close to one year, a reasonably stable light curve, and strong amplitude of more than five magnitudes in the visual (from 14th to 9th or better).  Unfortunately it's also becoming less-frequently observed by visual observers as time goes...

Matthew Templeton
July 18, 2010 - 11:22am

U Mon is an example of an RV Tauri star -- a pulsating variable showing pulsations with short-term regularity but with long-term irregular variations.  U Mon has a pulsation period (the length of time between two minima of equal depth) of around 92 days.  However, its long-term light...

Matthew Templeton
October 28, 2011 - 7:35am

This weeks light curve of the week highlights one of the challenges we face as a community that's attempting to collect long-term light curves.  U Tucanae is a bright southern Mira variable with a reasonably good chart and a decades-long history of observations by visual observers....

Matthew Templeton
February 1, 2011 - 2:57pm

V Bootis is a bright semiregular of the northern skies.  Earlier in the 20th century, V Boo had a larger amplitude and much more regular light curve than it did during this 5000-day span of data from the mid-1980's to mid-1990's.  V Boo is what we call a multimode...

Matthew Templeton
October 8, 2010 - 1:24pm

V Hydrae is a semiregular variable with a curious light curve.  The star appears to undergo cyclical dimming events with a period of 15 to 20 years.  The underlying pulsations don't seem to change much during these dimming events, which suggests that the star may be dimmed by...

Matthew Templeton
September 14, 2010 - 10:07am

V1057 Cygni is a young stellar object known as a FUOR or FU Orionis variable. These stars are still in the process of forming, accreting gas from the clouds they formed from.  FUORs undergo irregular episodes of brightening lasting for several years that are believed to be caused...

Matthew Templeton
January 23, 2013 - 10:33am

If a nova reaches naked eye brightness, and nobody sees it, does it exist?  Almost certainly.

While visiting AAVSO Headquarters in early February 2013, LSU's Brad Schaefer noted that since the Second World War, there has only been one nova to reach second magnitude, 1975'...

Matthew Templeton
September 14, 2010 - 10:24am

The symbiotic nova V407 Cyg made news headlines in mid-2010 when the Fermi Gamma-Ray Satellite unexpectedly detected gamma rays from its most recent outburst.  The nova was discovered in March of 2010, and has been followed by astronomers world-wide since then.  Surprisingly, the...

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