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HBC: Help

HBC - Herbig & Bell Catalog of Orion Pop. Emission-Line Stars


Overview

This database table contains the Third Catalog of Emission-Line Stars of the Orion Population (Herbig and Bell (1988)) which lists 735 pre-main sequence stars, members of the Orion Population, that have been observed with slit spectrographs or at equivalent resolution. It is intended to replace the Second Catalog of Herbig and Rao (1972). It gives accurate coordinates (many determined especially for this Catalog); light ranges for known variables; UBVRI data near maximum light; references to ultraviolet, X-ray, and radio observations, and to light curves; value of v sin i and the radial velocity when known; spectral type; equivalent width of the H-alpha emission line; references to spectral reproductions or scans and spectroscopic studies and to identification charts; and a classification (as a T Tau star, FU Ori object, etc.).

Catalog Bibcode

1988LicOB1111....1H

References

The University of California Lick Observatory Bulletin No. 1111 "Third Catalog of Emission-Line Stars of the Orion Population" G.H. Herbig and K. Robbin Bell. (June 1988)

Parameters

Alt_Name
First alternate name for the object, if given.

BII
Galactic latitude.

BV_Code
B-V color code. A `v` indicates that the colors show a substantial scatter at the same value of V.

BV_Color
B-V photometry.

For stars observed more than once, B-V Color contains the values observed when the star was brightest in V and a full set of UBVRI magnitudes were measured at essentially the same time. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Class
BROWSE Classification.

Coord_Refs
Coordinate references.

The coordinates indicated by `B` were determined by K. Robbin Bell with the Lick Automatic Measuring Machine on yellow (in most cases) plates of the Lick astrometric program. Usually 15 to 20 reference stars from the AGK3, with proper motions applied, were used. The epoch (minus 1900), rounded off to the nearest year, follows the `B`. The coordinates indicated by `Aw` were originally measured by C.A. Wirtanen, from blue plates of the Lick program, for the HRC. The epoch of those coordinates is approximately 1950. Neither `B` or `Aw` coordinates are considered to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those precessed to 1950.0 and later J2000.0 have not had proper motions applied and so remain at their original epoch.

The key to reference numbers is available from the HEASARC.

Dec
The Declination of the object in the selected equinox. This was given in 1950 coordinates to a precision of 0.01 seconds of time in the originating catalog on which this table is based.

Fourth_Alt_Name
Fourth alternate name for the object, if given.

H_Alpha_Code
H-alpha equivalent width code.

Different observers at different times sometimes quote very different results and it is often uncertain whether this represents real variation or is an instrumental effect; when real variations seem to be present, the mean given is followed by a `v`. An `hk` means that there is no information on H-alpha, but that emission is present in the H,K lines of Ca II. A `pr` means that H-alpha emission has been detected, but that no value for the equivalent width is available. An `abs` means that H-alpha is in absorption. An `em` means that unspecified emission lines have been observed. A `*` means that there is a remark.

The listing of remarks is available from the HEASARC.

H_Alpha_Refs
H-Alpha References.

The key to reference numbers is available from the HEASARC.

Hbc_Number
Catalog number assigned.

ID_Refs
Reference to an identification chart or photograph.

The key to reference numbers is available from the HEASARC.

Infrared_Refs
References for infrared magnitudes, spectrophotometry, and spectroscopy. However, low angular resolution far-infrared observations are not usually cited.

The key to reference numbers is available from the HEASARC.

Lcurve_Refs
Light curve references to photometric studies published since HRC. An `hrc` means that significant references in the Second Catalog are not repeated here.

The key to reference numbers is available from the HEASARC.

LII
Galactic longitude.

Location
The name of the bright nebulosity, dark cloud, cluster, association, or other object with which the star is associated or projected upon. A number of southern cloud complexes are designated by the abbreviations used by Schwartz; note that these are not the T-association designations of Kholopov (1959) or the R associations of Herbst (1975).

The prefixes used are

                  B    Barnard (1927)
                  FS   Feitzinger and Stuwe (1984)
                  Gum  the Gum Nebula region
                  L    Lynds (1962)
                  Ori  the Orion Nebula region
                  Sh   Sharpless (1959)
  

Mag_Code
Code to the magnitude system.

Name
This is the preferred designation of the object; if a variable star name has been assigned, that is always given preference.

Nebulosity_Flag
The HBC number is followed by `n` when the star is itself involved in, or illuminates bright nebulosity.

Object_Type
Object Type.

The abbreviations are

                  tt   T Tauri star
                  wt   weak-line T Tauri star, usually having W(H-alpha) less
                       than about 10 A and no other emission in the
                       optical region except Ca II H,K.  This includes
                       most of the so-called "Naked T Tauri Stars".
                  su   A star like SU Aur:  type late F to K, weak
                       emission at H-alpha and Ca II, very broad absorption
                       lines (v sin i > 50 km/s), and relatively high
                       luminosity.
                  ae   An Ae or Be star.
                  fu   A star of the type of FU Ori.
                  ?    Type uncertain:  the information is adequate, but
                       the object does not fit into any established
                       group; these stars are usually described in more
                       detail in the remarks.  Also, one of the original
                       criteria for membership in the Ae, Be group was
                       that the star illuminate bright nebulosity, but
                       now a number of irregular variables are known
                       which are photometrically and spectroscopically
                       similar but are not nebulous or associated with
                       obvious obscuration (UX Ori, WW Vul, SV Cep, BO
                       Cep, ...).  These questionable objects are also
                       marked `?` , or in some cases `a?`.
                  --   A blank means that the observational information
                       is inadequate.
  

Photo_Range
Photometric range, if the star is a known variable, expressed in the magnitude system indicated in Mag Code. Stars believed to be variable are indicated `var`. A number of stars not known to be variable have their mean, or estimated magnitudes, given if that magnitude is not visual or in the Johnson V system; otherwise that value is given in VMag.

Photo_Refs
Photometric references.

Values taken from the 4th edition (1985, 1987) of the General Catalogue of Variable Stars, or recent Supplements, are indicated by a `C`.

The key to reference numbers is available from the HEASARC.

Pos_Uncert_Flag
The position uncertainty flag is the colon ':'.

RA
The Right Ascension of the object in the selected equinox. This was given in 1950 coordinates to a precision of 0.1 arcseconds in the originating catalog on which this table is based.

Rad_Vel_Quality
The quality letter (`a`, `b`, `c`) expresses the uncertainty of the quoted velocity: `a` indicates a velocity of the highest quality, with an uncertainty of 1-2 km/s; `b` means a value with an uncertainty of 3-5 km/s; and `c` a velocity of still lower accuracy.

Rad_Vel_Refs
Radial Velocity References.

The key to reference numbers is available from the HEASARC.

Radial_Vel
Radial velocity (heliocentric, in km/s). In all cases, these velocities are from the absorption line spectrum. Velocities obtained with modern equipment usually replace those obtained at low dispersion by the early observers. For some stars we have not given the published velocities at all. Comments on several special objects (*) appear in the Remarks. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Radio_Refs
Radio references are to VLA observations or to detection of the star by some other means. No attempt is made to cite radio frequency molecular line observations of the cloud in the general neighborhood of the star.

The key to reference numbers is available from the HEASARC.

Remark_Flag
An asterisk (*) indicates that a remark is included for the source. The listing of remarks is available from the HEASARC.

RI_Code
A single letter (`J`, `C`) shows whether the R, I values are on the Johnson or Cousins system. An `i` indicates an instrumental (r,i) system; conversion relations for the photometry by Rydgren and co-workers are given in reference [407].

Second_Alt_Name
Second alternate name for the object, if given.

Spectral_Refs
References to the source of the spectral type quoted. Information which does not appear in the papers cited is usually from unpublished Lick material; a blank reference has that specific meaning.

The key to reference numbers is available from the HEASARC.

Spectral_Type
Spectral type.

The conventions are as follows: type `K7, M0` means either K7 or M0, while `K7-M0` means a type between K7 and M0. If the Li I 6707 A line has been detected in absorption, the type is followed by (Li). That a star is included in this Catalog indicates that emission lines have been detected (except in a very few special cases, all explained in the Remarks), so the suffix `e` for emission is not printed for types G and later, although it properly is a part of the classification; the `e` should be added if these types are quoted. However, in order to avoid possible misunderstanding, that `e` has been included for all the B, A, and F types where line emission is present. An `hrc` means that some significant information either in the Second Catalog, or referenced there, is not repeated.

Spectrum_Refs
Spectrum references show where the spectrum is reproduced (either photographically or as a scan), or the spectrum is described or discussed.

The key to reference numbers is available from the HEASARC.

Third_Alt_Name
Third alternate name for the object, if given.

UB_Code
U-B color code. A `v` indicates that the colors show a substantial scatter at the same value of V.

UB_Color
U-B photometry.

For stars observed more than once, U-B Color contains the values observed when the star was brightest in V and a full set of UBVRI magnitudes were measured at essentially the same time. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Ubv_Refs
Photometric references. The first number is the source from which the tabulated values are taken. Additional sources of UBV data follow. For stars having an extensive photometric history, a `*` means that details are in a remark. An `hrc` means that some information given in the Second Catalog is not repeated here.

The key to reference numbers is available from the HEASARC.

Uv_X_Ray_Refs
UV and X-ray References

V_Sin_I
The projected axial rotational velocity, given only to the nearest km/s. If no radial velocity value is given, then that reference is to the source of the v sin i; if a value for the radial velocity is given, then the second reference is (usually) the source of the v sin i. (A value of -32768 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

V_Sin_I_Code
V Sin i Code.

V_Sin_I_Sign
V Sin i Inequality sign.

VI_Code
V-I color code. A `v` indicates that the colors show a substantial scatter at the same value of V.

VI_Color
V-I values, usually obtained simultaneously (i.e., at maximum V) with the UBV data of Vmag, B-V Color, and U-B Color. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Vmag
V magnitude. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Vmag_Code
An `m` indicates stars for which there is only a small scatter about a mean V, or where a small-range cyclic variation is superposed upon irregular activity, and mean rather than maximum-V values are tabulated.

Vmag_Sign
Inequality sign to VMag. The conventional practice is followed in that `<` means "fainter than".

VR_Code
V-R color code. A `v` indicates that the colors show a substantial scatter at the same value of V.

VR_Color
V-R values, usually obtained simultaneously (i.e., at maximum V) with the UBV data of B-V Color and U-B Color. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)

Vri_Refs
References to the V-R and V-I data.

The key to reference numbers is available from the HEASARC.

Width_H_Alpha
Equivalent width of H-alpha emission (in A). These are from the original sources and are often mean values. (A value of -1.2E-34 displayed by the 'mat/dat' or 'dall' command indicates that no value is given.)


Contact Person

Questions regarding the HBC database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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