What happened to stellar astrophysics?

[Simfish]

I don't know what happened, but it seems that all the "hot" research is in fields like astrobiology, cosmology, computational astrophysics, and survey science (SDSS, LSST, etc). The most popular area of astro is still extragalactic stuff (which still makes up >50% of astro research), but even that isn't stellar astrophysics. Meanwhile, all the stellar astrophysicists in my department are all old and graying. I rarely see stellar astrophysics reach the front pages of department websites or science journals, except for those rare cases when a star does something unusual (see Betelgeuse).

Does anyone else have the same impression?

 

[Vanadium 50]

Did you consider that your experience is with one university? Other universities have different research emphases.

 

[Simfish]

That's true. Part of my impression also comes from science news websites like http://news.sciencemag.org/sciencenow/astronomy/?p=1. There are very few articles about what goes inside stars in the middle of their lives (other than the Sun).

 

[Simfish]

Hm, I looked at Colorado's site and there were only 2 people working on stellar astrophysics (and one of them was more into the interstellar medium). There were 2 others, but they are emeriti.

And Chicago has none at all.

Columbia has some though.

I posted the same thread on reddit and someone gave this response:

It was fairly moribund when I was in grad school in the 80s. :-| I personally think it's a shame — there's a tendency to think we've "solved" stellar evolution, but there's still a lot we don't understand.
OTOH, that makes it a good field to get into: Not much competition and you don't need really big telescopes to do good work.

 

[Vanadium 50]

Well, turn it around. What fraction of astronomers do you think should be working on this? 90% 50%? 10%? What fraction actually are?

 

[Simfish]

As for fraction, I would expect a higher fraction (maybe even 50%) in the past - especially given that most planetary scientists tend to work in Earth science departments. Of course, as there are so many new topics now, the fraction is probably going to be lower now. Given that most astronomy departments are rather small, it might only account to several professors per school. So it's not unexpected.

 

[amarante]

Why maybe astronomers are not working directly with stellar astrophysics, but all areas that you commented need the understanding of stellar physics. If you want to study the chemical evolution of a galaxy, you need good stellar models.

 

[hadsed]

I discussed this with my research advisor (we work in galactic dynamics). Stellar was the big thing in astrophysics until all the 'big problems' were solved. It seems like astrophysicists and astronomers look at galactic dynamics/evolution and dark matter evolution as the next big thing (though we're well into this big thing), and there are lots of big unsolved problems in those areas. This was mostly due to numerical modeling with computers.

 

[Simfish]

Oh interesting. I would have thought that numerical modelling would create new unsolved problems in stellar astrophysics.

 

[Ken G]

It is certainly true that stellar astrophysics is something of a "niche" topic these days (despite the irony that "stellar astrophysics" is literally redundant). You've heard the reason-- most of the problems are fairly old, so were either solved, or people lose interest in long-unsolved problems. They want the problems that just cropped up yesterday, like gamma-ray bursts or dark matter/energy. However, there are still plenty of active astronomers working on stars (moreso in Europe than the US, but even in the US), and there are lots of interesting problems to solve. There is always a tradeoff between going for the "hot" topic, and having to compete with the throngs, or seeking interesting "diamonds in the rough" that are largely untouched. There are certainly fewer of the former category in stellar astrophysics, but plenty of the latter.

Also, it should be mentioned that almost all areas of astronomy refer to stellar astrophysics in some way. The other areas like to imagine that stars are understood, so they can use them in their own stuff, but this is not necessarily true. For example, you can hardly do early galaxy formation without wondering about the physics of ultra-low-metallicity stars, which remains ill constrained and is an active area. And how can you use type Ia supernovae as a distance measure, without wanting to know something about what a type Ia supernova is? At the moment, that is not at all well understood-- it's not even known for sure if we have a single white dwarf accreting a teeny bit past its Chandrasekhar mass, or two white dwarfs merging well past that mass, let alone understand the details of the process. And as for core-collapse supernovae, it's still not even all that easy to get a supernova model that actually blows up, and how can one do galaxy evolution without wanting to know about how supernovae work? Or if one is interested in dark matter, one must understand mass/light ratios, and that's all stellar astrophysics, with many remaining outstanding questions.

 

[Chronos]

Once they figured out how gold was made, most stellar astrophysicists sought refuge in remote tropical islands with low taxes. The downside is post doc jobs were exported to attractive islanders.

 

[Simfish]

Just saw some statistics here (http://www.nap.edu/catalog.php?record_id=12951): shows some decline but not a big one.

Although it's only a survey with a small subset of astronomers, many of which are probably older than the average astronomer

 

[Dotini]

Perhaps someone could please explain the difference between stellar astrophysics and heliophysics? Stellar astrophysics may be languishing until the old guys die, but the young bucks at NASA are beavering away solving the problems of coronal hearing, solar wind, solar flares, CME's, etc.

For years NASA has been launching missions to study our sun and is making important new discoveries:

A 40 minute video from NASA on recent progress in understanding and predicting CME's.
http://www.youtube.com/watch?v=7m1XqyOOChY&feature=player_embedded

http://science.nasa.gov/science-news/science-at-nasa/2011/18aug_cmemovie/

Decades of questions above flares, CME's and the solar wind have been building up. Now, in the last five years, a fleet of some 16 NASA heliophysics missions are altering our whole view of our magnetic variable star, according to NASA scientists. In 2016, a mission to the corona itself is in the works!

One of the all-time great science mysteries is now a step closer to explanation. The surface of the sun, known as the photosphere, can reach temperatures of 5,000 degrees. To many it would seem logical that the temperature would lower further away from the sun. But, the outer atmosphere, known as the corona, has been shown to reach temperatures of over a million degrees.
http://www.physorg.com/news/2011-07-power-sun-intense.html
The study uses satellite observations to reveal that magnetic oscillations carrying energy from the Sun's surface into its corona are far more vigorous than previously thought. These waves are energetic enough to heat the corona and drive the solar wind, a stream of charged particles ejected from the Sun that affects the entire solar system.

Alfven waves were directly observed for the first time in 2007. Scientists recognized them as a mechanism for transporting energy upward along the Sun's magnetic field into the corona. But the 2007 observations showed amplitudes on the order of about 1,600 feet (0.5 kilometers) per second, far too small to heat the corona to its high levels or to drive the solar wind. http://www.sciencemag.org/content/317/5842/1192.abstract

Respectfully submitted,
Steve

 

[Astronuc]

The Impact of Asteroseismology across Stellar Astrophysics
http://www.kitp.ucsb.edu/activities/dbdetails?acro=asteroseismo-c11

The theme of the conference is to highlight the current status of our understanding of physical processes relevant to stellar interiors in the broadest sense, emphasizing the problems and the potential for using new observations of stars as physics probes. The field of stellar astrophysics is currently undergoing an observational revolution, thanks largely to the extensive stellar oscillation data recently obtained by the CoRoT and Kepler space missions. Thus a central aspect of the conference is to identify and explore physics issues (such as convection, diffusion, rotation, magnetic fields, radiative transport, equation of state...) that can be addressed by analyzing the seismic data. The program includes both theoretical talks that focus on stellar interiors and asteroseismic diagnostics, as well as observational talks that deal with problem and potential of the new seismic era.

Oct 24, 2011 - Oct 28, 2011

Maybe a good venue to find out "what has been happening in stellar astrophysics"


Edit/update (8/25/11): Solar Probe Plus = http://solarprobe.jhuapl.edu/
http://solarprobe.jhuapl.edu/science/index.php