Eric's Cool Astronomy Plots and Data

I love to make plots. How often they get published is another matter. Here are a few of my favorites, some of which might even be useful.

• Movie of the positions of nearby B-type stars and embedded star clusters (red circles) within ~500 pc. This still JPEG plot shows the positions of the B0-B2 stars (~>8 Msun, ~<35 Myr, future Type II supernovae!) within 500 pc along with the embedded clusters. The movie shows the positions of B-type stars by spectral subclass (*roughly* corresponding to a mean age and mass). Embedded clusters from the catalogs of Porras et al. 2003 and Lada & Lada 2003 are plotted as red circles. The B0-B2 stars are probable Type II supernova progenitors (>8 Msun). Note that many or most of the B0-B2 stars are spatially concentrated in groups ("OB associations"), and often they are near embedded clusters which have been forming stars within the past <1-3 Myr. To first order, the positions of the B0-B2 stars are showing where the past generation of embedded clusters was within the past ~5-20 Myr (their parent clouds having since been disolved through winds and supernovae). Data is based on parallaxes and positions from van Leeuwen (2007) with spectral types compiled within the original Hipparcos catalog. Typical distance errors are ~10% at 100 pc and ~50% at 500 pc, and magnitude limits and extinction preferentially remove distant stars. One point from the plot is: there are often large numbers of supernova progenitors in the vicinity of the largest, most populous embedded clusters (and indeed some of their kin may have supernovaed 'recently')
  
  
• Primordial disk fraction vs. age for young cluster samples (or the "Haisch-Lada^2 plot"). "Protoplanetary" disks appear to be nearly ubiquitous around stars at ages of <1 Million years, but roughly half are gone by age ~2 Myr, and they are nearly all gone by age ~10 Myr. This plot includes results from spectroscopic surveys for T Tauri stars that are actively accreting, as well as infrared surveys for optically thick disks (using mostly the Spitzer Space Telescope). T Tauri stars that show signs of accretion spectroscopically (e.g. strong Halpha emission) usually have evidence for optically thick disks in the infrared, and vice versa. Other authors have presented revised versions of this plot over the years, so this one is simply a 2009 update (for some other recent versions of the plot, see Hillenbrand 2005 and Hernandez et al. 2008). There appear to be real cluster-to-cluster differences in the disk fraction at a given age, and the evolution of disk fraction appears to be a function of stellar mass and multiplicity. The plot appears in a recent review that I wrote for the Subaru conference in Kona on Exoplanets and Disks (Mamajek 2009, arXiv:0906:5011).
  
  
• Here are some useful datasets for making color-magnitude plots of nearby stars and looking at their 3D (U,V,W) Galactic space velocities. I combined the revised Hipparcos catalog (van Leeuwen 2007) with the spectral type and V magnitudes listed in the original Hipparcos catalog (ESA 1997) to produce some data tables. HIP2008_SpT_Mv_75pc_plxSN8.dat gives HIP & HD numbers, astrometry (positions, proper motions, parallaxes), V and Hp magnitudes, B-V and V-I colors, and derived distances (beware of significant figures), and absolute magnitudes for ~13k stars apparently within 75 parsecs (parallax > 13.33 mas) with parallax errors smaller than 12.5%. So these stars ostensibly represented the nearest stars with negligible reddening (i.e. they are within the Local Bubble). The file HIP2008_SpT_Mv.dat represents the same data, but for all (nearly 111k) Hipparcos stars with positive parallaxes in the van Leeuwen revised Hipparcos astrometry catalog. The file HIP2008_UVW_SpT_Mv.dat contains astrometry, color-mag, and spectral type data for ~34k stars with postive Hipparcos parallaxes and measured radial velocities from the compiled catalog by Gontcharov (2006). The first several columns include the mean radial velocity along with the derived UVW (3D) Galactic velocities for those ~34k stars with measured radial velocities.
  
  
  Note that these are *not* the tables used for the following plots, which were based on the Kharchenko et al. ASCC-2.5 compiled catalog of astrometry and photometry. (I did not have time to update these plots using the revised Hipparcos astrometry).
  
  
  
• Color-magnitude diagram (B-V vs. Mv) for stars within 80 pc, with color coding by spectral type
  
  
• Color-magnitude diagram (B-V vs. Mv) for stars within 30 pc, with solar metallicity evolutionary tracks
  
  
• Color-magnitude diagram (B-V vs. Mv) for the young (~5 million-year-old), nearby (145 parsecs) OB association Upper Scorpius.
  
  
• Bluest Main Sequence B-V color for a given age/isochrone
  
  
• Effective temperature (Teff) vs. stellar mass (M/Msun) for main sequence stars: data for binary stars with dynamical masses from and Hillenbrand & White (2004). Best fit polynomials are listed.
  
  
• Distance (parsecs) vs. age (in billions of years; Gyr) for the nearest 100 solar-type dwarf stars. Plot made from data in Table 13 of Mamajek & Hillenbrand (2008). The ages were inferred from chromospheric activity levels from the F7-K2 main sequence stars, using the revised rotation vs. age and rotation vs. activity calibrations from this paper. You can think of this as the distribution of ages of the nearest (potential) planetary systems to the Sun, for the nearest Sun-like stars in our Galactic neighborhood.
  
  
• Pre-MS contraction time versus stellar mass: How long does it take a pre-main sequence star to contract and reach the zero-age main sequence? It takes a 1 solar mass star roughly 44 million years to contract to the point at which hydrogen fusion stabilizes (reaches the main sequence). Plot was contructed using the D'Antona & Mazzitelli evolutionary tracks.
  
  
• Standard Solar Model - distribution of mass, temperature, and luminosity inside the Sun (from Bahcall & Pinsonneault 2004).
  
  
• Watch Proxima Centauri run!
  
  
• Cumulative number of exoplanet discoveries versus time. It appears that the number of known extrasolar planets is doubling every 29 months or so -- displaying a behaviour similar to Moore's law, but with a slightly longer time constant. For illustation's sake, if you assume that the Milky Way has 400 billion stars, and each star averages one planet per star, then this relation(?) would predict that we will complete our census of these worlds in 2081 (hmm, I wouldn't bet on it). Data taken from the Extrasolar Encyclopedia.
  
  
• The distribution of known O-type stars, viewed from above the Galactic plane, with spiral arms (from Vallee 2002). O-stars are from the Maiz-Apellaniz et al. catalog, where I calculated distances using the Mv and (B-V)o values from Martins et al. 2005. Here I assume the Sun is 8 kpc from the Galactic center. The anticorrelation of the O-stars with the arms appears to be due to the magnitude-limited nature of the O-star catalogs. There tend to be more dark molecular clouds in the "gaps" where there are no O-stars.
  
  
• B-V vs U-B color-color plot of OB and A0V stars. The plot gives an improved fit for deriving intrinsic (B-V) colors for OB stars using Johnson's Q-method (I had noticed that some of the formulae for deriving intrinsic B-V from the Q-method for high-mass members of the Sco-Cen OB association were giving more unphysically negative reddening values (E(B-V)) than one might suppose just from photometric errors. This plot shows why -- the previous calibrations do a somewhat poor job of fitting the "blue envelope" of colors for unreddened nearby B-type stars by attempting to force their fit through (B-V, U-B = 0, 0) for A0V stars.
  
  
• "The Lithium Plot": A crude age indicator for cool stars. This is a plot of stellar effective temperature (Teff) versus the equivalent width of the Li I 6707A line for stars in clusters of "known" age. Stars appear to be born with a more-or-less "cosmic abundance" of Li (roughly 1 Li atom for every 500 billion hydrogen atoms!). Li is burned in stellar interiors at relatively low temperatures (~1-2 megakelvin), but it is burned relatively slowly in stars like the Sun since they have thin convective shells that do not allow the Li to reach great depths and high temperatures.
  
  
• Solar Chromospheric Activity vs. time (1975-2008). Using full disk solar K-index measurements from the NSO (Livingston et al. 2007) and converted to chromospheric activity index logR'HK via relations in Radick et al. (1998) and Noyes et al. (1984).
  
  
• Solar Chromospheric Activity vs. International Sunspot Number (1974-2008). Using full disk solar K-index measurements from the NSO (Livingston et al. 2007) and converted to chromospheric activity index logR'HK via relations in Radick et al. (1998) and Noyes et al. (1984). Sunspot data are from the Solar Influences Data Analysis Center. The correlation is very strong (Pearson r = 0.98), and the minimum logR'HK value is roughly -4.95 for sunspot number (ISN) equal zero.
  
  
• Mark Heyer's (UMass) velocity map of Taurus as traced by 12CO emission. This movie passes you "through" the Taurus molecular clouds (one of the nearest star-forming complexes) in velocity space, as traced by detections of a carbon monoxide line with the FCRAO radio telescope. Red lines are polarization vectors.
  
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