Astronomy of Planets

Transcription

1 McDonald Press Releases: Triumphs and Ques7ons Globular Clusters Rotate at Heart Astronomers Discover Ancient Solar System with Five Earth- sized Planets Black Hole Chokes on a Swallowed Star Astronomers Disprove Claims that Two 'Goldilocks Planets' Might Support Life

2 yes, DO pay a*en,on to what s behind the curtain!

3 h*p://mcdonaldobservatory.org/news/releases/2014/05/09

4 Globular Clusters Rotate at Heart Fig. 1. Velocity fields for the 11 GCs in our sample. The plots show the veloci,es that we derive on a per- pixel basis. Grey areas indicate spectral pixels that were rejected from the kinema,c analysis based [on weak signal]. The cross indicates the cluster center, while the straight solid line shows the kinema,c posi,on angle. In all plots the x axis is aligned with the east- west direc,on and posi,ve x values point west while y increases towards the north.

5 try just one cluster note that the box is 2 arcmin on each side

6 M3 a good image from the ground Here is an anima,on of cluster rota,on: h*ps://

7 How big did the velocity image get? 2 arc- min

8 How big did the velocity image get? 2 arc- min

9 VIRUS- W??? The new measurements of these globular cluster cores were only possible with the help of the MPE- built instrument VIRUS- W. VIRUS- W allows the scien,sts to simultaneously measure more than 260 spectra in their field of view, determining the mo,on of stars to an accuracy of a few kilometers per second. That means that for a given globular cluster, one night at the Smith Telescope with an observing,me of a few hours is enough to determine the velocity field at the core of a cluster.

10 Astronomers Discover Ancient Solar System with Five Earth- sized Planets Kepler- 444 hosts five Earth- sized planets in compact orbits. The planets were detected from the dimming that occurs when they transit the face of their parent star, as shown in this ar,st's concept.

11 h*p://mcdonaldobservatory.org/news/releases/2015/0127.html

12 Transit light curves for the five planets orbi,ng Kepler From panels a to e: Transits of planets Kepler- 444b, Kepler- 444c, Kepler- 444d, Kepler- 444e, and Kepler- 444f, respec,vely. The photometric light curves have been phase- folded on the orbital period of the planets to show the observed data as a func,on of orbital phase. Individual data points are shown as gray dots. Blue dots correspond to a binning of individual data points.

13 But it is a binary star system also

14 Semi- major axes of planets belonging to the highly- compact mul,ple- planet systems Kepler- 444, Kepler- 11, Kepler- 32, Kepler- 33, and Kepler- 80. Semi- major axes of planets in the Solar System are shown for comparison. Note that all planets in the Kepler- 444 system are interior to the orbit of the innermost planet in the Kepler- 11 system, the prototype of this class of highly- compact mul,ple- planet systems.

15 Black Hole Chokes on a Swallowed Star h*ps:// v=dmomg2seav8&feature=youtu.be

16 h*p://mcdonaldobservatory.org/news/releases/2015/0126.html

17 ROTSE?

18 ROTSE loca,ons

19 To narrow it down, they studied Dougie in various ways. They made ultraviolet observa,ons with the orbi,ng Swil telescope, and took many spectra from the ground with the 9.2- meter Hobby- Eberly Telescope at McDonald. Finally, they used computer models of how the light from different possible physical processes that might explain how Dougie would behave how it varies in brightness over,me, and what chemical signatures it might show and compared them to Dougie s actual behavior.

20 h*p://mcdonaldobservatory.org/news/releases/2014/07/03

21 this is the only sensible picture I could find in the journal paper

22 transit of Venus, spo*ed stars Astronomers search for exoplanets by measuring shils in the pa*ern of a star's spectrum the different wavelengths of radia,on that it emits as light. These "Doppler shils" can result from subtle changes in the star's velocity caused by the gravita,onal tugs of orbi,ng planets. But Doppler shils of a star's absorp,on lines also can result from magne,c events like sunspots origina,ng within the star itself giving false clues of a planet that does not actually exist.

23 H alpha varia,ons???

24 H- alpha is a stellar ac,vity indicator H- alpha 6563Å

25 real spot, simulated spots