# Tag Info

9

There are a thousand or so stars within 50 light years, most are very dim red dwarfs, and most are unexceptional. If we invent "names" then we would have to learn the names of all the stars. If we want to name all the stars that can be seen with a telescope, we would have to come up with a billion or so names. The idea of naming stars rapidly becomes ...

8

As far as I know, there is no standard that defines valid characters for a stellar designation. Sometimes people write using Greek letters (e.g. "α Centauri") and there are many odd catalogue notations. I would not trust that star designations could not contain commas or pipes (aka vertical bar, |), although I think it would be rare. The IAU has ...

6

Variable stars might challenge this. A distant Mira type variable or recurrent nova could have been at its minimum when the (for example) Gaia catalogue was being assembled, but appear in an amateur photographs. These stars undergo very large variation in brightness. Mira can increase in brightness by 8 magnitudes, so it is not inconceivable that an ...

5

There is a very nice project called d3-celestial by Olaf Frohn on github. In contains a data file describing the Milky Way as polygons, see here. A demo showing this Milky Way can be found here. And even better, the source for this data is cited, pointing to the Milky Way Outline Catalog by Jose R. Vieira. Depending on your project, the json format from d3-...

5

Best chance would be the Hipparcos catalogue. The first set of Gaia data will be released Mid-September 2016, but I don't know if it will be more accurate than Hipparcos already. All stars within 11,462 light years of Earth. That won't be easy. These catalogues have a magnitude (brightness) cutoff. Brighter, more massive stars can be seen further away ...

4

The Hipparcos catalogue by van Leeuwen (2007) contains all the information you require, plus estimates of distance from parallax. It is open and free to use for scientific purposes. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I%2F311 The direct page that describes the catalogue contents and ftp site is http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/311 ...

3

For Gaia EDR3： Note (G1): Note on magnitude errors: They are obtained with a simple propagation of errors with the formulas e_Gmag = sqrt((-2.5/ln(10)*e_FG/FG)**2 + sigmaG_0**2) e_GBPmag = sqrt((-2.5/ln(10)*e_FGBP/FGBP)**2 + sigmaGBP_0**2)) e_GRPmag = sqrt((-2.5/ln(10)*e_FGRP/FGRP)**2 + sigmaGRP_0**2)) with the G, G_BP, G_RP zero point uncertainties ...

3

That is because what is measured is a flux and the flux errors are in the DR2 catalogue. Since magnitudes are based on the logarithm of the flux, then there is no straightforward correspondence (although it matters little if the error bars are less than a few hundredths if a magnitude). Simple error propagation formulae give |\Delta G| \simeq \frac{2.5}{\... 3 The SIMBAD link might be there just because Osterbrock's 2004 AAS presentation about the interferometer mentioned an observation of Betelgeuse. This would be consistent with the policy stated in Wenger et al. 2000: No assessment is made of the relevance of the citation in terms of astronomical contents: the paper can be entirely devoted to the ... 3 Note that astronomers generally are not concerned with hemispheres, so it is unlikely that you will find a catalog that is only for a specific hemisphere. Catalog generally cover the entire sky. Also, most catalogs are for either stars or deep sky objects (galaxies, nebulae, and so on). I have not seen a catalog that includes both stellar and non-stellar. ... 3 For me, it looks like Max Wolf discovered the movements of the Wolf 359, see the (German) original publication from 1918 "Zwei Sterne mit großer Eigenbewegung in Leo," but he does not mention which previous observations existed: Fun fact: The object was observed from Königstuhl, a peak next to the city of Heidelberg, Germany. That was back in the ... 3 If you search by position in the CDS Simbad database by position it will give you entries in all three of these catalogues. If you search by name, then it will look for matched objects in these three catalogues. I am unsure what the matching algorithm is - it must cross-correlation on the position and look for objects within an appropriate matching radius, ... 3 As the names and numbers are essentially arbitrary, the Hipparcos designation cannot be calculated from the Bayer or Flamsteed designation. Instead you have to look up the star in a database. There is a HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index on line. (Direct link)You can get a computer to do the look up for you. Or if you only have a small number of ... 3 You should use 3CRR. It contains a few sources of large angular diameter that were missed in the original surveys. https://en.wikipedia.org/wiki/Third_Cambridge_Catalogue_of_Radio_Sources#3CRR https://3crr.extragalactic.info/ 3 You can use VizieR to retrieve the whole catalogue (3C and revised 3C). VizieR is an online astronomical catalogue that allows you to access a quite comprehensive list of catalogues (16,929, as of today); you can easily query and extract all kind of data from this online tool. 3 The Hipparcos results can be used as an earlier epoch to improve the astrometry produced by Gaia. This was the linchpin of data release 1 (DR1), but less important in DR2 and DR3, because the astrometry of Gaia alone is so much better in general. An exception to this is bright stars where much data is still missing in DR3, but can be found in the Hipparcos ... 2 According to Google, the longest name for any star is “Shurnarkabtishashutu”, the Arabic for “under the southern horn of the bull”. The star is known as Zeta Tauri. You could also scroll thru Wikipedia's list of star names for different countries. 2 Hipparcos measured the parallax (distance) of stars, along with their colors in two wavelength regions (B_Tycho, "blue" and V_Tycho, "green"). Using the color information you can make a reasonable estimate for the stellar temperature, and coupled with the parallactic distance, this would allow you to get an estimate for the stellar radius. But Hipparcos ... 2 FK5 is based on optical observations. ICRS is based on radio data. Radio observations (ironically) are much higher accuracy than optical through the application of long baseline interferometry. Other than extremely accurate astrometry (fractions of an arcsec), they are essentially identical. 2 This is because the ICRS has an origin at the barycenter and this is not the same as the center of the Sun (the heliocenter). The heliocenter is offset from the barycenter (although it's still within the radius of the Sun) and varies with time, primarily due to the perturbations of Jupiter and Saturn. If you use BarycentricTrueEcliptic it will work fine: ... 2 The transformation to x,y,z coordinates, starting from the RA, Dec and a distance (as given in the HYG catalogue) is a simple trigonometric exercise, since the x,y,z (in this case) is referred to a coordinate system aligned with the equatorial coordinate system.x = d \cos({\rm RA}) \cos({\rm DEC}),y = d \sin({\rm RA}) \cos({\rm DEC}),z = d \...

2

It's pretty simple: those are the names of the named stars, also called 'proper names'. All other designations you show in your table are catalogue numbers assigned to them. While these names are historically grown, the official names are assigned / decided by the IAU to avoid confusion and standardize them.

2

As you’ve discovered, there are a lot of different catalogs out there, and many ways to search them. It would help if you could narrow your question a bit - what kind of data are you looking for? You seem to want stellar masses at least - what else? As noted above, there are few stars for which mass is measured directly, but there are robust ways of ...

2

$\eta$ Cassiopeiae A has an estimated mass of 0.972 M$_\odot$, an estimated temperature of 5973 K, and a B-V color index of ~0.58[1]. In addition to the spectrum of the star, we look at these and other properties when attempting to classify main sequence stars. You can see a table [here] which shows the bulk properties of each spectral type that we can use ...

2

A catalogue is just that what one would understand usually: it's a table of stars with their coordinates and possibly other properties like relative or absolute brightness, proper motion etc. The accuracy depends on how it was created, thus mostly is expression of the available instrumentation, processing pipeline and its limitations. They usually are output ...

2

30.0 mean "variable". If you click on the "Ptm" column header, you get a pop-up window including "Note (2) : codes used for the magnitudes:"; below that is a list of codes, including "30.0 = variable (var. in published catalog)"

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