Gliese Catalog Explorations
The Gliese catalog is a catalog of nearby stars, stars within ~20 pc, or those thought to be within ~20 pc. (Wikipedia entry) It was first published in 1957, and has been updated a few times since then. This is the most recent update. Let's explore some of the properties of these stars using IRSA services.
Get the catalog together
- Read or at least scan the PASP paper. How many stars are in this catalog?
- Get the updated catalog from Vizier (direct link to text catalog).
- In order to get this source list into IRSA tools, you need to get it into IPAC Table Format, which is just ASCII but it has to have the right formatting. If you get it "close enough" to IPAC table format, you can pass it through IRSA's IPAC Table Validator which can make formatting corrections. Here is the IPAC table I constructed from these sources. I don't know if the wiki will preserve the formatting of that sufficiently, so you may wish to save it, make sure it has a .tbl extension, and pass your copy through the Table Validator to be safe.
Explore these stars
- Use this source list and IRSA's Catalog Search Tool to find 1-to-1 matches for these stars in 2MASS, WISE/AllWISE, and Gaia DR2. There's currently no way to easily merge these lists within IRSA. You can work with each catalog independently or merge them yourself - if you use 1-to-1 matching in the Catalog Search Tool, each output merged list will have one line per source, so matching up sources across catalogs is trivial. Create an IPAC table (and pass it through the Table Validator to be sure it's compliant).
- Within a catalog, from the Catalog Search Tool results, you can change what is plotted. Try these things:
- Because you have Gaia data, you have distances to these stars. However, parallax is tabulated, not distance. Because the IRSA plotting can do simple mathematical manipulations including logarithms, you can use the information there to make an absolute color-magnitude diagram. (Hint: phot_g_mean_mag- (5*log10(1000/parallax) - 5).) Which stars are white dwarfs in your diagram? Which stars are giants in your diagram? Use SIMBAD to investigate a few of those stars and see if you have successfully identified white dwarfs, giants, and main sequence stars. Which are the intrinsically brightest and faintest stars in this sample? Make more plots (you can make histograms!) to identify the range of distances you can find in this sample. Are they all really within ~20 pc? Which is the closest/farthest?
- Try 2MASS J-H vs. H-Ks. Why does this look the way it does? What is it telling you? (hint: Are there any stars subject to reddening?) Explain the structure in this diagram. Which features are artifacts and which are real? Which stars have the most reddening? Explore them with SIMBAD (find papers and scan them) to learn more about them to see if they are really known to be highly reddened.
- Try WISE-1 vs. WISE-1-WISE3. Why does this look the way it does? What is it telling you? (hint: Are there any stars in this list that have a mid-IR excess?) Explain the structure in this diagram. Which features are artifacts and which are real? Which stars appear to have an excess? Use SIMBAD to explore what is known about some of these apparent IR excess stars. Use Finder Chart to decide if you believe the WISE-3 (and WISE-4) detections. Which stars have legitimate IR excesses?
- Advanced: try 2MASS J vs. H-Ks. Use the parallax as above to make absolute J vs. H-K. Why does this look the way it does, e.g., different than the optical CMD? What is it telling you about these stars?
- Use the SED feature within the IRSA Radar tool to explore Vizier's SEDs for a few of these targets. Do they look like what you expect? (Radar is the box on the IRSA main web page. If you put in a galaxy name, it pulls an SED from NED; if you put in a star name, it pulls an SED from Vizier. NED are vetted SEDs, but only for galaxies. Vizier just pulls all the catalog measurements within a given radius, converts the units, and displays it, so it is not vetted.)
Relevant topics from the rest of the wiki
(e.g., these are the "Lego bricks" to go investigate in order to build this "Lego kit.")