May 28, 2017

Astro-Challenge:When will T Pyxidis Finally Pop?

T Pyxidis; a supernova in the making? (Credit: M. Shara & R. Williams STS, R. Gilmozzi ESO, & NASA)

T Pyxidis; a supernova in the making? (Credit: M. Shara & R. Williams STS, R. Gilmozzi ESO, & NASA)


   Earlier this year, the astronomical community was wowed by the eruption of the star U Scorpii. As reported last year in this space, U Sco is a recurrent nova, a flare star that undergoes outburst at irregular intervals. Less than 10 recurrent novae have been identified. The initial action was caught by two Florida based amateurs, and demonstrates that hands on, observational astronomy is still alive and well even in the modern age of astronomical automation. This week, as the waning gibbous moon slides out of the evening sky, I’d like to turn your attention to another of these rare beasts; T Pyxidis. Located in the constellation Pyxis, the Mariner’s Compass, this is one of those unimaginative southern hemisphere constellations thrust upon us in the 18th century. Visually unremarkable, it contains a handful of deep sky objects and clears the horizon sufficiently in the spring evenings for observers in the southern United States to perform routine observations. T Pyxidis itself is a binary system consisting of a white dwarf cannibalizing a sun-like star. When enough in falling matter accumulates, T Pyx flares up from its normal barely detectable magnitude +15.5 to +7.0, almost naked eye visibility. This has happened at roughly 20 year intervals in the years 1890, 1902, 1920, 1944, 1966…and then T Pyx fell silent. We are currently 44 years and counting for an outburst, and this is definitely a star worth continuous scrutiny. The light curve is that of a slow nova, rapidly brightening over a couple of nights, fluctuating at its peak brightness for about a month, and then fading out over proceeding months. T Pyx is a prime candidate for a galactic Type Ia supernova, and at a distance of 3260 light years, could put on quite a show. Of course, said final act could occur tonight, or 10 million years from now; but this current lull makes you think; there has to be a lot of material accreting up there! Its coordinates are;

R.A: 09h 04m 41.5s

Dec: -32 22m 47.5s   

And for an uber-cool finder chart that Sky & Telescope produced a few years back, follow this link… (hint: for use in the field, take the chart and  invert the colors in Paint or Photoshop!)

Good luck, and with a little patience, YOU could be the next amateur to catch T Pyx in the act!

The Astro-term for this week is Chandrasekhar Limit. This is the mass limit of a body in which electron degeneracy pressure can push outward against gravitational collapse. First calculated by Indian astrophysicist Subrahmanyan Chandrasekhar in 1930, this mass is usually given as 1.44 solar masses. Below this limit, a white dwarf and an accompanying planetary nebula will occur; above this mass limit, a core collapse supernova will occur, leaving behind a pulsar or a black hole. T Pyxidis has to be very near its very own Chandrasekhar Limit, with the amount of in-falling mass it is accumulating… will it pop in our lifetime?

15.10.09:Watch the Hubble Repair Online!

Astronauts conduct final repairs in orbit. (Credit: NAS/STS-125).

Astronauts conduct final repairs in orbit. (Credit: NAS/STS-125).

Its out! After much waiting, PBS’s flagship science program NOVA has at last begun putting the new season up online for viewing! This will assure that those of us who now exclusively get their media via the Internet, such as ourselves here at Astroguyz HQ, receive our weekly fix. And the change-over could not have been timelier; the first episode we previewed was Hubble’s Amazing Rescue, the STS-125 mission to save the Space Telescope earlier this year. The episode follows the dangerous repair mission from the tank training on the ground to the problems encountered and overcome while in orbit. The personalities of astronauts Mike Massimino (a.k.a. The “Tweeting astronaut”) and Megan MacArthur shine through in this engaging episode. And hey, we learned a thing or two; I’d heard about the nut capture plate for instance, but had never seen it in action. Lots of stunning IMAX footage was shot during this amazing mission for eventual use on the big screen. Be sure to give the NOVA site a peek as new episodes are now going up!

14.9.9:U Scorpii:A Nova in Waiting?

A Cataclysmic Variable Star. (Image credit & copyright Mark A. Garlick and has been used with permission. Please do not use this image in any way whatsoever without first contacting the artist).

A Cataclysmic Variable Star.

(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...]

View your own Star of Bethlehem.

    Over the years, much ink (real and cyber) has been spilt over the astronomical origins of the Star of Bethlehem. Biblical references are scant in regards to what the wise men may have seen; we know that the star “went before them…” every morning until it lay over the manger; the rest was history. But what was it?

[Read more...]

The Contributions of Amateur Astronomers to Modern Science

(Author’s note; the essay below was a paper submitted recently by yours truly as part of my quest for a bachelors degree in science teaching. I’ve posted it here pretty much intact. Some explanations on the graphs have been expanded; I thought it was a shame for all of my research on the subject to go to waste. The bibliography is also included.)

Today, the modern science of astronomy is growing like never before. New technologies are opening up unseen vistas scarcely imagined just twenty years ago. [Read more...]