December 18, 2017

19.02.11: V1647 Orionis-A Request for Observations.

This past Tuesday, a call for observations went out from the American Association for Variable Star Observers (AAVSO) for observations past and present of a very poorly understood variable. In AAVSO Special Notice #235 Dr. Colin Aspin of the University of Hawaii has requested images past and present of the area surrounding M78 and the object known as McNeil’s Nebula.

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AstroEvent: When will Epsilon Aurigae Brighten?

One of the strangest variable stars is worth watching this spring.  Back in 2009, we alerted viewers to monitor the curious variable Epsilon Aurigae. Once every 27.06 years, this star dips nearly a magnitude in brightness down to about +3.8, markedly discernable to the naked eye. This drop lasts for over a year before Epsilon Aurigae returns to its former self. This spring should witness such an occurrence.

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Astro-Event of the Week-Redder than Red: V Hydrae.

This week, we here at Astroguyz are going to introduce you to a star that isn’t on the top 10 star party faves, but perhaps should be; V Hydrae. [Read more...]

25.04.10-First Extra-solar Magnetic Loop Recorded.

Radio-Interferometry has really shown its stuff as of late. Recently, astronomers have used a collaboration of radio telescopes based planet-wide to study a familiar variable star; Algol in the constellation Perseus. Known since Arabic times as “The Demon Star,” Algol is an eclipsing binary, where two stars are locked in a 5.8 million mile embrace and “eclipse” each other from our vantage point. This explanation has been known since 1889, but radio astronomers have added another unique feature to the pair; a long pair of magnetic loops connecting the two stars. “This is the first time we’ve seen a feature like this in the magnetic field of any star other than the Sun,” stated William Peterson of the University of Iowa. The scopes linked included the NSF’s Very Long Baseline Array, Green Bank, and the Effelsburg Radio telescope based in Germany.  Collectively, the setup is known as the High Sensitivity Array. Algol is about 93 light years distant, and is a variable star that can be easily monitored by even beginning amateurs with the naked eye.

15.04.10- Do We Know the Future of our Sun?

Our modern understanding of stellar evolution states that our Sun is a middle-aged main sequence star, destined to bellow up into a Red Giant in a few billion years and eventually wind up as a degenerate white dwarf embedded in a shroud of a planetary nebula. Looking out at the stars in various stages of evolution in our galaxy, we see systems that have done just that. These Red Giants often exhibit a rhythmic oscillation as their atmospheres swell and contract, but about one third also display a longer five year variation that scientists do not completely understand. Now, a study conducted by the European Southern Observatories’ Very Large Telescope (VLT) is looking into this mystery by studying 58 sun-like stars towards their elderly Red Giant stage located in the Large Magellanic Cloud. Known since the 1930’s, this mystery has baffled astronomers. “Astronomers are left in the dark, and for once, we do not enjoy it,” stated Christine Nicholls of Australia’s Mount Stromlo Observatory. Some of the long term pulsations could be explained by the presence of an unseen binary companion, but not all. This phenomenon is of special interest to astrophysicists because our own Sun may one day throw similar temper tantrums. Could stellar evolution be in need of tweaking?

Object of the Week; Gamma Arietis.

Double stars are often overlooked as astronomical targets, but tend to hold up well under light polluted, urban skies. I often show folks bright doubles at star parties to great effect, and a mental vocabulary of about a dozen or so can add to the usual crowd pleasers such as the Moon and bright planets. One of my favorite fall targets is Gamma Arietis, in the constellation Aries, the Ram.

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14.9.9:U Scorpii:A Nova in Waiting?

(Image credit & copyright courtesy of Mark A. Garlick; used by permission.

Please do not use this image in any way whatsoever without first contacting the artist).

Recurrent novae are among the rarest of beasts. While one-off galactic nova come and go throughout the year, recurrent novae are among those very few stars that have been known to exhibit nova-like flares multiple times. This week, I turn your attention towards U Scorpii, a known recurrent nova in the head of the constellation Scorpius. As the bright Moon is currently out of the evening sky, now and next month is the time to peek at this unique star before it slides behind the Sun. First discovered in 1863 by English astronomer N.R. Pogson during an outburst, U Scorpii stands as one of the fastest recurrent nova known, [Read more...]