Red spirals are not dead
The discovery of a population of red spiral galaxies has caused astronomers to questions the relation between galaxy color and morphology: a closer look at their star formation rates reveals a clearer picture.
Two (or three?) black holes in one galactic center
It has long been known that galaxies can merge; thus, we should expect their central supermassive black holes to interact as well. However, our ability to study this is limited as most mergers happen in the distant universe. The exceptional nearby source CID-42 can be explained by a recent binary or triple supermassive black hole interaction, giving astronomers a rare chance to witness the repercussions of such an event.
First light from a super Earth
Last year, I reported on how the mystery of 55 Cancri e was resolved. In this Letter, Demory et al. observe the secondary eclipses of 55 Cnc e (when the planet passes behind the star), allowing them to determine the planet’s temperature. At 3,800 degrees Fahrenheit: this super Earth is not looking like a good vacation spot. They are also able to explore possible compositions for the planet.
This star lives in exciting times, or, How did Betelgeuse make that funny shape?
Sometimes we see strange shapes when we look through our fancy telescopes and we’re left wondering how they formed. How did the rings and “pearls” of SN1987A form? Or the hexagonal cloud pattern on Saturn? The star Betelgeuse – famous for being Orion’s left shoulder – presents another unusual geometric appearance.
The discovery of pulsations in the white dwarf J1840: the first of its kind
Title: SDSS J184037.78+642312.3: The First Pulsating Extremely Low Mass White Dwarf Authors: J. J. Hermes, M. H. Montgomery, D. E. Winget, Warren R. Brown, Mukremin Kilic, Scott J. Kenyon First Author’s Institution: UT Austin, TX97% of all stars — those with initial masses less than about 8 solar masses — end their lives as white dwarfs (WDs), hot objects with roughly the mass of the Sun but with the radius of the Earth. They have virtually no internal source of energy and so simply cool with time. Some of the coolest white dwarfs have been around for quite a while and are probes of conditions in the early Universe. They are also tracers of galaxy evolution and can be used to date stellar populations. Understanding their nature is key if we are to use white dwarfs for these purposes.Asteroseismology of pulsating white dwarfs is one way to learn about the interior structure of these fascinating objects. Asteroseismologists use stellar vibrations in much the same way as seismologists use earthquakes to study Earth’s interior (see this astrobite and this one). The authors of this paper are on a hunt for DAV WDs. For those of us who don’t speak white dwarf lingo, that’s a white dwarf (“D”) with a hydrogen atmosphere (the “A” subclass) that pulsates (“V” for variable). There are actually quite a few of these DAV WDs, but the 150 we know of are fairly massive for white dwarfs, with masses between 0.5 and 1.1 solar, and are believed to have carbon-oxygen cores. These authors are after a rarer beast: a pulsating helium-core white dwarf, which would have...
Simulating the unseen: learning about Jupiter’s unknown impactor through simulations
The impact of comet Shoemaker-Levy 9 was a remarkable event: in 1994, a comet, torn into pieces during a close approach with Jupiter two years prior, crashed into Jupiter. It was the first collision between two solar system bodies to ever be observed, and the effects on Jupiter’s atmosphere (see the figure below) were visible for months. At the time, Harrington et al. (2004) predicted that it would be hundreds of years before such an event occurred again. But two and a half years ago, another object collided with Jupiter. No one witnessed the collision, but amateur astronomer A. Wesley noticed a dark streak with properties closely matching those seen after the impact of SL-9. Because of these similarities, it is believed that this feature was the result of an impact.