DwarfArchives.org M dwarf Archive Search Form Help

You can find the help you need for any aspect of this search form. Use the table of contents below to jump to a specific section, or simply browse the entire contents.


General notes

The M Dwarf archive is a collection of spectra that Davy Kirkpatrick has acquired over the years. It is not a complete list of all M dwarfs, nor is there any real selection criteria, aside from the object being an M dwarf. We make them available for use as spectral "standards," in the sense that if you need the spectrum of an M3, you can get it here.

For each of the M dwarfs listed we have several common names, 2MASS colors, spectral types and spectra. The spectra just have the basic header information (date, exposure time, instrument). Each of these fields are searchable in the form.

The server for the archive database and search engine is a dual core 2.8 GHz Pentium with 2 GB RAM running Fedora Core 4 (x86_64). The database itself is running under PostgreSQL 8.1.5 which is accessed from the web form through custom built PHP 5.2.0 scripts. The form, as well as these help pages, are written in HMTL.

The server was funded by a NASA Small Research Grant, administered by the American Astronomical Society. We thank them for their generosity.


Name Search Help

This section is used if you only want information about a particular object whose name you know in full or in part. The search is a very simple routine that tries to match the entered text with the Gl/GJ name, the LHS name, some other common name, or the 2MASS designation, as chosen from the drop down box. Keep in mind that the names in the database are the full object names and not the shorthand names routinely used in the literature. Also, the entered text must be exactly the same as the entry in the database for a valid result to be returned. Since most of us don't know the full names exactly, wild cards can be used to help with the areas of the name you about which you are unsure.

For example, suppose you want to return the information about the object commonly referred to as "2MASS 0746+2000." If you entered this text into the name search field, no result would be returned, since the full discovery name is "2MASSI J0746425+200032" and the full 2MASS PSC designation is "2MASS J07464256+2000321." A wild card must be included with the input name to ensure a proper match. An entry of "2MASS*0746*2000*" Will return the object you want.

Supported wildcards are:


Radius Search Help

With this section it is possible to search the contents of the archive around a specific position. Enter the length of the search radius in the radius box; the units of this radius is determined by the units listed in the drop down box. Possible units are arcsec, arcmin, or degrees. There is currently no limit for the size of the search radius.

You can either search around specific coordinate (by selecting the Coordinate option) or upload a table of names and/or positions (by selecting the Upload option). The coordinate conversions and name resolving is performed through IRSA's Lookup Service. Information about what types of input that are accepted can be viewed here.

If you want to search around several objects, you can use the table upload form. The table must be a simple ASCII file with the form:

| name | ra | dec |

These are the only three columns allowed for the time being. Each of the values under the column headers must be contained within the pipes ("|") and the column headers must have those exact names ("name", "ra", and "dec").

Examples

For files with names and coordinates, the name is not sent to the name resolver; the search is performed around the input position. This is to allow for names that will not be resolved by SIMBAD.

The routine to compute the great circle arc distances is derived from the IDLAstro routine gcirc.pro.


Search Form Help

This form is used to create custom searches of the archive. Almost every aspect of the archive can be constrained during a query. The logic used between fields is set to AND (ex. jmag<16 AND ra>14.0). Logic within a field can be set to AND or OR using the Limit Logic column.


Display Query

If the box is checked (default), then the SQL string used for the database query is returned along with the results. The SQL string is not returned if the box is not checked. Having the SQL string returned is useful for those trying to learn SQL and for tracking bugs in the search scripts.


Sort Order

The results of the search can by ordered according to many of the search fields listed below. This section determines if the results are ordered by Ascending or Descending values for the chosen field. If one of the spectral type fields is the sort field, then Ascending sorts from early to late spectral type and Descending sorts from late to early.


Search Form Columns

Name

The name of the field. These are usually the names of the columns in the database.

Description

A short description describing the field.

Select

A checked box in this column denotes a field that is to be returned with the query. Some fields are returned automatically when related fields are selected. For example, selecting jmag to be returned also returns jmag_error. The help listings for each field below describes additional fields that are returned. Any number (>0) of fields can be selected for return.

Sort by

A mark in this column indicates which field is to be used for ordering the results. The results are ordered according to ascending or descending values, as determined by the selection in the Sort Order box. Only one field can be selected as the ordering field.

Low Limit

Use these input boxes to set lower numerical limits for any of the aplicable fields. Except for the spectral type fields, the input values can be floats or integers. Please see the help listing for spectral type below for information regarding how to set limits for this field.

All entries must be preceded by =, >, or >=.

Limit Logic

These radio buttons are used to determine the logic used for the upper and lower limit constraints. The logic choices are AND and OR. In most cases the AND logic will suffice (ex. return all objects with a J magnitude greater than 12 AND less than 15). However, in some cases, the OR logic might be better. If you want to search for objects with right ascension crossing the 0/24 hour boundary, then you would need to use the OR logic. For example, to search for objects between a right ascension of 20 and 4 hours, set the Low Limit to ">20", the Up Limit to "<4" and the Limit Logic to OR.

Upper Limit

Use these input boxes to set upper numerical limits for any of the applicable fields. Except for the spectral type fields, the input values can be floats or integers. Please see the help listing for spectral type below for information regarding how to set limits for this field.

All entries must be preceded by =, <, or <=.

Measurement

Not every object in the archive has an entry for every field. The checkboxes in this column can be used to return only those objects for which a measurement exists in this archive (check the Req box) or only those objects for which a measurement does not exist in the archive (check the Mis box).

The actual test that is performed when one of these boxes is selected is a check for a null value for the field. Values that are not null are assumed to contain a measurement.

Units

This column contains the units that are used for both input and ouput.


Search Form Fields

gl_name The designation from the 3rd Catalog of Nearby Stars (Gliese & Jahreiss). Selecting this returns the Gl/GJ name of the object. Not all objects in this catalog have Gl/GJ designations. This option is not supported. This option is not supported. This option is not supported. This option is not supported. This option is not supported. There are no units for this field lhs_name The designation from the Luyten Half-Second catalog (LHS numbers) or Luyten Palomar catalog (LP). Selecting this returns the LHS or LP designation of the object. Not all objects in this catalog have LHS or LP designations. This option is not supported. This option is not supported. This option is not supported. This option is not supported. This option is not supported. There are no units for this field other_name An alternate name for the object. This can come from any number of difference catalogs and sources. Selecting this returns the alternate name of the object. Not all objects in this catalog have alternate names. This option is not supported. This option is not supported. This option is not supported. This option is not supported. This option is not supported. There are no units for this field designation The 2MASS point source designation. The source designation takes the form:
  • '2MASS Jhhmmssss[+/-]ddmmsss': Source found in the 2MASS All-Sky Point Source Catalog
Selecting this returns the 2MASS designation of the object. This designation provides a reference for the photometry and a representation of the object's coordinate in hexigesimal format. If an HTML form is returned, then the finder chart is linked to the designation. We use the IRSA FinderChart service to provide realtime charts for all targets. This is much slower than our custom-made PDF finder charts, but also much less of a burden on our limited time. This option is not supported. If you want to sort by position, then use the sort by buttons for ra or decl instead. This option is not supported. This option is not supported. There are no nulls in this column. All objects in the archive have a 2MASS designation. There are no nulls in this column. All objects in the archive have a 2MASS designation. There are no units for this field
ra The J2000 right ascension of the object. The coordinate is derived from the 2MASS designation. Selecting this field returns a floating point value of the right ascension in hours. A sexigesimal value of the right ascension can be obtained from the designation. Selecting this causes the results to be ordered according to ascending or descending values of the right ascension. This button is selected by default. Three basic formats are supported for right ascensions input into this field:
  • 12.2342185
  • 12 39 29.94
  • 12:39:29.94
A comparison operator (=,>, >=) must also be present.
Three basic formats are supported for right ascensions input into this field:
  • 12.2342185
  • 12 39 29.94
  • 12:39:29.94
A comparison operator (=,<, <=) must also be present.
There are no nulls in this field. There are no nulls in this field. hours
decl The J2000 declination of the object. The coordinate is derived from the 2MASS designation. Selecting this field returns a floating point value of the declination. A sexigesimal value of the declination can be obtained from the designation. Selecting this causes the results to be ordered by ascending or descending declination. Three basic formats are supported for declinations input into this field:
  • +45.45923
  • -38 43 93.3
  • +57:29:38.4
A sign (+ or -) must be present as must the comparison operator (=,>, >=).
Three basic formats are supported for declinations input into this field:
  • +45.45923
  • -38 43 93.3
  • +57:29:38.4
A sign (+ or -) must be present as must the comparison operator (=,<, <=).
There are no nulls in this column. There are no nulls in this column. degrees
j_2mass The 2MASS PSC J-band magnitude of the object. Selecting this field returns the J magnitude and the associated error (j_error_2mass). Selecting this orders the results according to ascending or descending J magnitude. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for j_2mass. Selecting this requires the returned results to have null values for j_2mass. magnitudes j_error_2mass The photometric error associated with the J-band magnitude. This field is automatically returned when the j_2mass field is selected. Selecting this orders the results according to ascending or descending J magnitude error. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for j_error_2mass. Selecting this requires the returned results to have null values for j_error_2mass. magnitudes h_2mass The 2MASS PSC H-band magnitude of the object. Selecting this field returns the H magnitude and the associated error (h_error_2mass). Selecting this orders the results according to ascending or descending H magnitude. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for h_2mass. Selecting this requires the returned results to have null values for h_2mass. magnitudes h_error_2mass The photometric error associated with the H-band magnitude. This field is automatically returned when the h_2mass field is selected. Selecting this orders the results according to ascending or descending H magnitude error. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for h_error_2mass. Selecting this requires the returned results to have null values for h_error_2mass. magnitudes ks_2mass The 2MASS PSC Ks-band magnitude of the object. Selecting this field returns the Ks magnitude and the associated error (ks_error_2mass). Selecting this orders the results according to ascending or descending Ks magnitude. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for ks_2mass. Selecting this requires the returned results to have null values for ks_2mass. magnitudes ks_error_2mass The photometric error associated with the Ks-band magnitude. This field is automatically returned when the ks_2mass field is selected. Selecting this orders the results according to ascending or descending Ks magnitude error. Limits inserted here can be entered as a float and must be preceded by (=,>, >=). Limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this requires the returned results to have non-null values for ks_error_2mass. Selecting this requires the returned results to have null values for ks_error_2mass. magnitudes jh_2mass The 2MASS (J-H) color of the object. Selecting this field returns the (J-H) color and associated error (jh_error_2mass) of the object. Selecting this orders the results according to ascending or descending (J-H) color. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both j_2mass and h_2mass are non-null. This option is equivalent to selecting the measurement required option for both j_2mass and h_2mass separately. Selecting this option requires that either j_2mass or h_2mass are null. magnitudes jh_error_2mass The photometric error associated with the (J-H) color. The error is computed as sqrt(j_error_2mass2 + h_error_2mass2). This field is automatically returned when the jh_2mass field is selected. Selecting this orders the results according to ascending or descending (J-H) error. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both j_error_2mass and h_error_2mass are non-null. This option is equivalent to selecting the measurement required option for both j_error_2mass and h_error_2mass separately. Selecting this option requires that either j_error_2mass or h_error_2mass are null. magnitudes hk_2mass The 2MASS (H-Ks) color of the object Selecting this field returns the (H-Ks) color and associated error (jh_error_2mass) of the object. Selecting this orders the results according to ascending or descending (H-Ks) color. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both h_2mass and ks_2mass are non-null. This option is equivalent to selecting the measurement required option for both h_2mass and ks_2mass separately. Selecting this option requires that either h_2mass or ks_2mass are null. magnitudes hk_error_2mass The photometric error associated with the (H-Ks) color. The error is computed as sqrt(h_error_2mass2 + ks_error_2mass2). This field is automatically returned when the hk_2mass field is selected. Selecting this orders the results according to ascending or descending (H-Ks) error. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both h_error_2mass and ks_error_2mass are non-null. This option is equivalent to selecting the measurement required option for both h_error_2mass and ks_error_2mass separately. Selecting this option requires that either h_error_2mass or ks_error_2mass are null. magnitudes jk_2mass The 2MASS (J-Ks) color of the object Selecting this field returns the (J-Ks) color and associated error (jk_error_2mass) of the object. Selecting this orders the results according to ascending or descending (J-Ks) color. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both j_2mass and ks_2mass are non-null. This option is equivalent to selecting the measurement required option for both j_2mass and ks_2mass separately. Selecting this option requires that either j_2mass or ks_2mass are null. magnitudes jk_error_2mass The photometric error associated with the (J-Ks) color. The error is computed as sqrt(j_error_2mass2 + ks_error_2mass2). This field is automatically returned when the jk_2mass field is selected. Selecting this orders the results according to ascending or descending (J-Ks) error. Lower limits inserted here can be entered as a float and must be preceded by (=,>, >=). Upper limits inserted here can be entered as a float and must be preceded by (=,<, <=). Selecting this option requires that both j_error_2mass and ks_error_2mass are non-null. This option is equivalent to selecting the measurement required option for both j_error_2mass and ks_error_2mass separately. Selecting this option requires that either j_error_2mass or ks_error_2mass are null. magnitudes spectral_type The spectroscopically determined spectral type. These spectral types are based on the optical spectrum (~0.6 - 1.0 μm). All objects have a spectral type. Selecting this box returns the spectral type. Choosing this will sort the results according to ascending or descending spectral type. Lower limits for spectral type searches are entered here. Enter spectral types as a combination of a spectral class (K or M) and a decimal subclass (0, 0.5, 1, ..., 9.5). Examples are M3 and M5.5. Be certain to precede the entry with a comparison operator (=,>, >=). Upper limits for spectral type searches are entered here. Enter spectral types as a combination of a spectral class (K or M) and a decimal subclass (0, 0.5, 1, ..., 9.5). Examples are M3 and M5.5. Be certain to precede the entry with a comparison operator (=,<, <=). This is not an option. All objects have spectral types. This is not an option. All objects have spectral types. none spectra This field shows the three searchable metadata available for the spectral files. The three parameters are Telescope/Instrument, Observation Date, and Exposure Time. Selecting this field dictates if any spectra are to be returned in the query. If selected, then a spectra column us returned with the results. This column contains the spectrum meta data, a link to a graphical preview of the spectrum, a link to the ASCII data, and a check box used to select spectra for downloading. There are buttons at the top of the result form that can be used to select all spectra, unselect all spectra, and download selected spectra. This is not an option. With this menu you can select specific telescopes and/or instruments to be returned in the search. It is possible to select multiple entries in this menu by using the Control key with the left mouse button (individual selections) or the Shift key with the left mouse button (select a range of entries). Lower limits for the Observation Date represent the cutoff for the earliest date (i.e. oldest data). Dates are entered with the following format: YYYY-MM-DD. Lower limits for Exposure Time represent the shortest exposure time returned in the search. The time is entered as a floating point number. Upper limits for the Observation Date represent the cutoff for the latest date (i.e. newest data). Dates are entered with the following format: YYYY-MM-DD. Upper limits for Exposure Time represent the longest exposure time returned in the search. The time is entered as a floating point number. This is not an option. All objects in this catalog have spectra. This is not an option. All objects in this catalog have spectra. There are no units on the Telescope/Instrument field. The unit for Observation Date is a date with the following format: YYYY-MM-DD. The unit for Exposure Time is seconds. More questions? Contact our Help Desk