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This category contains 181 posts

How Many Exoplanets are Habitable?

The answer to the above question, according to a new analysis of data from NASA’s Kepler mission, may be roughly one-third. Continue reading

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Planets, stars, and their magnetic interaction

This paper investigates the interaction between close-in (semimajor axis a<0.15AU) massive planets (a.k.a. “hot Jupiters'') and their host (late-type) stars. Two possible mechanisms for interaction are tidal and magnetic, with the focus of this paper being the latter. The pioneering work on the topic of stellar activity enhancement (such as dark spots, faculae, etc) due to planet interaction is by Cuntz et al. (2000). You can see related contributions about stellar activity on previous astrobites posts. Continue reading

The First High Redshift Quasar from Pan-STARRS

Morganson et al. announce the discovery of the first quasar discovered by Pan-STARRS. The newly detected quasar is a Broad Absorption Line quasar at a redshift of 5.73 +/- 0.02 with a z band magnitude of 19.4, a luminosity of 3.8×1047 erg/s, and an estimated black hole mass of 6.9×109 solar masses. Continue reading

Making stars the right size

Stars form in environments that are characterized by vastly different densities, pressures and metal content. Yet the sizes of the stars formed don’t vary substantially (as measured by the median mass). Why don’t the properties of the clouds out of which stars fragment have a stronger influence on the result? Why is there a characteristic stellar mass? Why is this mass scale similar to that for nuclear burning (the process that fuels stars)?
(photo: NASA via LANL, https://www.llnl.gov/news/newsreleases/2005/NR-05-11-10.html) Continue reading

Crowd-sourcing Science: Planet Hunters find two new planet candidates

Planet Hunters is a Citizen Science project, aiming to analyze the slew of data from the Kepler Space Telescope. Planet Hunters look for transit signals in the data, which cause the light from the star to dim periodically.This project is designed to complement the efforts of other scientists to analyze the data using computer algorithms. This paper presents results of the first two planet candidates to be identified using this method, demonstrating that this type of citizen science project is a valuable tool for exoplanet detection.
Continue reading

Ultra-Luminous X-ray Sources and Intermediate Mass Black Holes: A lost middle sibling in the black hole family tree?

* Paper title: Optical Emission of the Ultraluminous X-Ray Source NGC 5408 X-1: Donor Star or Irradiated Accretion Disk? * Authors: F. Grisé, P. Kaaret, S. Corbel, H. Feng, D. Cseh, L. Tao * First author’s affiliation: University of Iowa Continuums seem to be the name of the game in astronomy.  On more than one occasion, astronomers have … Continue reading

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