MOCAdb Brown Dwarf Photometry Explorer

Axes

Filter quantities

X axis

Type Quantity Quantity 2

Y axis

Type Quantity Quantity 2

Filters

Spectral range

Highlight designations

Use MOCA OIDs

Highlight OIDs

Highlight BANYAN group

Minimum BANYAN probability 90%

De-emphasize data with X error larger than De-emphasize data with Y error larger than

No points selected.

Using URL Parameters

You can open this page with predefined controls by appending query-string parameters to the URL. Use ?param=value for the first option and &param=value for each additional option. For shared links, prefer the canonical parameter names listed below.

Common examples

?xaxis_type=color&yaxis_type=absolute_magnitude&xaxis_value_1=mko_jmag&xaxis_value_2=mko_kmag&yaxis_value_1=mko_jmag&moca_oid=602,10995
?xaxis_type=spectral_type&yaxis_type=absolute_magnitude&yaxis_value_1=mko_jmag&moca_oid=602
?xaxis_type=spectral_type&yaxis_type=spectral_index&yaxis_value_1=h2o_j&spt_range=L2+
?mock=1 for a network-free local sample dataset.

Axis parameters

Parameter	Allowed values	Effect
`xaxis_type`, `yaxis_type`	`spectral_type`, `teff`, `color`, `absolute_magnitude`, `spectral_index`, `equivalent_width`	Chooses the observable shown on each axis. Defaults are `xaxis_type=color` and `yaxis_type=absolute_magnitude`.
`xaxis_value_1`, `yaxis_value_1`	Photometry system ID, spectral-index ID, or chemical-species ID	Chooses the main quantity for axes that need one. Simplified photometry values use `simple:J`, `simple:H`, `simple:K`, or `simple:W2`. Advanced photometry values use detailed IDs such as `mko_jmag`, `mko_hmag`, `mko_kmag`, `wise_w1`, and `wise_w2`. For spectral indices, use IDs such as `hcont` or `h2o_j`. For equivalent widths, use a chemical-species ID such as `li`.
`xaxis_value_2`, `yaxis_value_2`	Photometry system ID	Chooses the second band for `color` axes. For example, `xaxis_value_1=mko_jmag&xaxis_value_2=mko_kmag` plots `J-K`.

Catalog and filter parameters

Parameter	Values	Effect
`spt_range`	Spectral type range such as `L2+`, `>=L2`, or `M6-Y2`	Limits the plotted catalog by adopted spectral type. An underscore may be used instead of a hyphen in ranges. Highlighted OIDs are still requested even when they fall outside the range. Default is `L2+`.
`moca_oid`	Comma-separated OIDs, for example `602,10995`	Highlights specific objects and requests them from the backend even when they are outside the current spectral range or hidden optional filters.
`designation`	One designation per parameter, or comma-separated designations	Preselects designation-based highlights for objects already loaded in the current catalog. Use repeated parameters for several names, for example `?designation=WISEA%20J0000&designation=2MASS%20J0001`.
`highlight_aid`	Comma-separated association IDs	Highlights BANYAN Sigma members in the selected association, for example `highlight_aid=ABDMG`.
`highlight_ya_prob_min`	`0`-`100`	Sets the minimum BANYAN Sigma young-association probability for highlighted association members. Default is `90`.
`oid`	Comma-separated OIDs	Alias for `moca_oid`.
`xerr_max`, `yerr_max`	Number, or blank/`none`/`null`/`nan`	De-emphasizes points whose propagated X or Y uncertainty exceeds the threshold and excludes those points from automatic axis limits. If omitted, the app applies axis-specific defaults where available; T_eff axes default to 100 K.
`spherex_classification`	Comma-separated SPHEREx visual-vetting classifications, or `missing`	In an authenticated private-table session with a SPHEREx magnitude or `spx…` spectral-index axis, shows only measurements whose own source spectrum has a selected classification. With all measurements shown, this filtering happens in the browser; with best-measurement selection enabled, it is applied by the backend before ranking. Missing includes NULL classifications, absent vetting rows, and source spectra whose package has no mapped vetting table. With no selection, all classifications are shown.
`sequence_smoothing`	`0.5`-`8` subtypes	Sets the total width of the centered, distance-weighted data window. The default is `2.5` subtypes. Weighted medians and weighted median absolute deviations (MADs) are evaluated every tenth of a subtype, then the fitted sequence and MAD scatter are smoothed over one-third of the selected width.
`max_objects`	Positive integer, or `0`/`none`/`uncapped`/`all`	Controls the safety cap for broad source queries, especially when including photometric spectral types or requesting spectral ranges earlier than L0. The default broad-query cap is 5,000 objects, and larger numeric requests are clamped; `0`, `none`, `uncapped`, or `all` explicitly requests no cap.

Boolean display options

Boolean options are enabled with 1, true, or yes. Omit the parameter, or use 0 or false, to leave the option off.

Parameter	Default	Effect
`errors`	`false`	Shows propagated X and Y error bars.
`best_measurement`	`false`	Plots only the lowest-uncertainty measurement of each selected quantity for each brown dwarf. NULL uncertainties rank last, and row ID breaks ties deterministically.
`sed_teff`	`false`	With a `teff` axis, restricts T_eff values to SED analyses from `Sang23` or `Fili15`. T_eff rows are always de-duplicated per object by quality, uncertainty, then row ID.
`teff_jitter`	`30`	Adds deterministic T_eff jitter from 0 to 200 K in either direction so overlapping points can be separated.
`xaxis_log`, `yaxis_log`	`false`	Displays the corresponding T_eff axis logarithmically. This option is ignored for other axis types.
`photdist`	Axis-dependent	Includes objects with photometric distance estimates. It defaults on when neither axis is absolute magnitude and off otherwise. Photometric-distance symbols are used only when an absolute-magnitude axis depends on those distances. An explicit URL value or user choice is preserved.
`binaries`	`false`	Plots known binaries. They are drawn with open marker symbols and listed in the legend.
`photspt`	`false`	Includes photometric spectral type estimates. This can be slow because it broadens the source query.
`bickle_spt`	`false`	In private-table mode with a spectral-type axis, keeps adopted non-low-gravity spectral types and uses Bickle et al. spectral types for the low-gravity branch.
`azul_byw_sample`	`false`	In private-table mode, highlights objects listed in `pcat_azul_byw_sample_jul16_2026`.
`advanced_photometry`	`false`	Shows all detailed MOCAdb photometry system IDs instead of the simplified band list.
`agecolor`	`false`	Colors objects with BANYAN association ages by age and shows objects without ages in gray.
`gravitycolor`	`false`	Colors objects by gravity class: field, beta, gamma, delta, or subdwarf. Beta/gamma classes are folded into gamma. Mutually exclusive with `agecolor`.
`richgravity`	`false`	Uses separate marker categories for Field grav. / α, Int. grav. / β, Very low grav. / γ, pec(red), pec(blue), other pec, sd, d/sd, esd, and usd.
`sequence_fit`	`false`	Fits each non-spectral-type axis with weighted medians as a smooth function of fractional spectral type, draws the resulting sequence as a thick black line, and shades the local ±1 weighted-MAD region in gray.
`sequence_selected_only`	`false`	Restricts the fitted sequence to data points selected in the plot.

Backend aliases

The backend also recognizes include_photdist, include_photometric_dist, include_photspt, and include_photometric_spt. The visible page controls are synchronized to the canonical photdist and photspt parameters, so those canonical names are preferred for URLs you intend to share.

Performance Preload

For the current spectral range and highlighted objects, this preloads the full in-memory dataset: photometric spectral type estimates, photometric distances, designations, all photometry bands, all spectral indices, equivalent widths, Teff values, age data, and sequence overlays. This can take a few minutes, but once it finishes the app can switch most axes and display options much faster. Some large optional private datasets may be omitted from this upfront load to keep the preload practical.

Not loaded.

Keeps the controls, flushes downloaded data, and reloads from MOCAdb.