Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

HD 172030


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

A GLIMPSE into the Nature of Galactic Mid-IR Excesses
We investigate the nature of the mid-IR excess for 31 intermediate-massstars that exhibit an 8 μm excess in either the Galactic LegacyInfrared Mid-Plane Survey Extraordinaire or the Mid-Course SpaceExperiment using high-resolution optical spectra to identify starssurrounded by warm circumstellar dust. From these data we determineprojected stellar rotational velocities and estimate stellar effectivetemperatures for the sample. We estimate stellar ages from thesetemperatures, parallactic distances, and evolutionary models. Using MIPS[24] measurements and stellar parameters we determine the nature of theinfrared excess for 19 GLIMPSE stars. We find that 15 stars exhibitHα emission and four exhibit Hα absorption. Assuming thatthe mid-IR excesses arise in circumstellar disks, we use the Hαfluxes to model and estimate the relative contributions of dust andfree-free emission. Six stars exhibit Hα fluxes that implyfree-free emission can plausibly explain the infrared excess at [24].These stars are candidate classical Be stars. Nine stars exhibitHα emission, but their Hα fluxes are insufficient to explainthe infrared excesses at [24], suggesting the presence of acircumstellar dust component. After the removal of the free-freecomponent in these sources, we determine probable disk dust temperaturesof Tdisk~=300-800 K and fractional infrared luminosities ofLIR/L*~=10-3. These nine stars may bepre-main-sequence stars with transitional disks undergoing diskclearing. Three of the four sources showing Hα absorption exhibitcircumstellar disk temperatures ~=300-400 K,LIR/L*~=10-3, IR colors K-[24]<3.3,and are warm debris disk candidates. One of the four Hα absorptionsources has K-[24]>3.3 implying an optically thick outer disk and isa transition disk candidate.

Halpha emission objects in a dark region in Aquila and Scutum.
Not Available

Second Supplement to the Mount Wilson Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1949ApJ...110..387M&db_key=AST

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:Écu de Sobieski
Right ascension:18h38m03.52s
Declination:-04°55'20.6"
Apparent magnitude:9.402
Proper motion RA:16.4
Proper motion Dec:-9.2
B-T magnitude:9.836
V-T magnitude:9.438

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 172030
TYCHO-2 2000TYC 5121-864-1
USNO-A2.0USNO-A2 0825-12478426
HIPHIP 91368

→ Request more catalogs and designations from VizieR