Stellar abundance information provides one of the primary tools for understanding everything from the evolution of the Milky Way galaxy to the structure and mineralogy of exoplanets. The Hypatia Catalog is a composite stellar abundance catalog that is comprised of multiple literature sources of high-resolution, spectroscopic data which was originally introduced in Hinkel et al. (2014) and subsequently updated in Hinkel et al. (2016, 2017). A breakdown of all the included catalogs (with > 20 stars), including information regarding their telescopes, models, and techniques, is given in this table, where a description of the columns can be found at the bottom of the About page. The NASA Exoplanet Archive data data page is here.
The plot can be filtered using the 3 filter boxes on the top right that provide minimum and maximum values (either can be left blank in place of infinity). Changes are enacted by pausing for a few seconds or clicking the “Submit” button at the bottom of the plot. Options for the filter criteria can be accessed by clicking on the dropdown menu that says “none” as default. From the dropdown menu, if an element is chosen from the Periodic Table, the filter changes to become an X/Y ratio where both the numerator and denominator can be specified. In addition to the neutral state of the element, if the singly ionized element has been measured, the “II” next to the element can be selected (see the About page). Stellar properties are listed along the bottom of the drop down menu in addition to planetary properties. If any of planetary properties are chosen, then the graph will show only planet hosting stars. The X and Y axes can plot any of the element ratios, stellar properties, or planet properties. Additionally, the Z-axis, or color, can be initialized to show another dimension.
To move, adjust, zoom, or generally change the properties of the plot, the tools listed vertically along the right side of the plot can be toggled to make the appropriate adjustments. Additionally, the figure can be saved by clicking the “Save” button near the bottom.
While the plot showing “Elements and Properties” enables a user to look at either planet hosting stars or stars that are not currently known to have planets, we wanted to provide the ability to look at the two populations simultaneously. Therefore, we have provided a 1D histogram that shows both stars with and without planets. Similar to the other plot, the filter bar can be used to make cuts on those stars analyzed. Additionally, the histogram can viewed either in terms of total number of stars in a bin or normalized (by checking the “Normalize the histogram” toggle) according to the bin with most number of stars, which has a height of 1 by definition.
For those users wishing to change some of the more nuanced aspects of the stellar abundances within the Hypatia Catalog and Database, we provide the ability to make adjustments. In order to ensure that all of the stellar abundances within Hypatia are on the same baseline, all individual catalogs have been renormalized to the same solar normalization. The default is Lodders et al. (2009). As part of the database, the user can change the solar normalization to be with respect to Asplund et al. (2009), Grevesse et al. (2007), Asplund et al. (2005), Grevesse & Sauval (1998), and Anders & Grevesse (1989). If the user would like to view the stellar abundances with respect to the solar normalization employed by each of the catalogs individually, the “Original” option can be chosen. We note that abundances originally published in absolute A(X) notation cannot be shown when the "Original" normalization is selected, since no solar normalization was specified by the authors at the time of publication. However, when a solar normalization is chosen by the Hypatia Catalog Database user, then all abundances -- [X/H], [X/Fe], or A(X) -- are placed on the same solar scale. The absolute abundances, namely without a solar normalization, can be viewed by choosing “Absolute.”
The Hypatia Catalog is a multidimensional database, which utilizes all stellar abundances measurements made for an element within a star by +200 catalogs (see Hinkel et al. 2014, Fig 3). Therefore, to provide a 2-dimensional table, those measurements must be collapsed or reduced. The toggle “If an element ratio is in multiple catalogs” changes the reduction method to either take the median (default) or mean of all measurements of an element in a star.
Finally, while the Hypatia Catalog and Database is unbiased in its inclusion of datasets, we recognize that the user may wish to look exclusively at particular catalogs. We have provided a toggle that allows the user to switch between “Excluding” or “Allowing” individual catalogs as they see fit.
The table is filtered using the filter bars at the top. The columns that are shown in the table can be adjusted using the “Add/remove columns” button, which gives the user the ability to include individual elements (shown as [X/H] unless the Absolute solar normalization is chosen). Additionally, all stellar properties (RA, Dec, XYZ position, distance, disk, spectral type, V mag, B-V, UVW galactic velocity, Teff, and logg) and all planetary properties (planet letter, period, planet mass, eccentricity, and semimajor axis, where applicable) can be shown in the table (see the About page).
The user can also view the spread (or error) in the stellar abundances. Per the original Hypatia Catalog paper (Hinkel et al. 2014), the spread is defined as the range in the stellar abundance measurements when determined by different groups measuring that same element within that same star. The spread is an exceptionally useful tool to truly define how consistently an element is measured within the star between different datasets, which is why we utilize it as the overall abundance precision, see Hinkel et al. (2016) for more details.