5073A V/73A Third Cat Em-Line Stars of the Orion Population G H Herbig K R Bell Lick Observatory Bull. No. 1111 ??? ??? 1988 1988LicOB1111....1H Combined data stars, pre-main sequence This Catalog 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-aplha 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.)

This is the third up-date of a listing of the pre-main sequence stars, both certain and probable, that have emission lines and that have been observed with slit spectrographs or at comparable resolution. The first (Herbig 1962) contained 126 entries, the second (Herbig and Rao 1972: hereafter HRC) had 323, while the present Catalog contains 735. Not only has the total number of stars increased due to a higher level of observational activity and the improvement of spectroscopic instrumentation, but there is a greater variety of significant information to be referenced: for example, there was no occasion in earlier listings to mention v sin i's, radial velocities, far-ultraviolet, X-ray or radio-frequency data. The classification scheme for pre-main sequence stars (described below) has also been modified as the result of improved observational information. In order to accommodate such new information as well as more accurate astrometric coordinates within a double page, 264-column format, it has been necessary to omit some information that is relevant and would have been useful in some cases: (a) IRAS identifications are not included. (b) Light curve classifications are not included, partly because such traditional observations have not kept pace with the volume of other information. Instead, references are given to sources where such information as exists may be found, except in cases where rotational modulation has been detected; such results are given in the Remarks to Table 1. (c) No references are given to polarization information; however, that subject has recently been surveyed very thoroughly by Bastien (1988). (d) The "emission line intensity" classification of the Second Catalog, a rather subjective quantity but all that was available in 1972, has been replaced by the equivalent width of H-alpha emission, which is now readily determinable as the result of the widespread use of linear, red-sensitive detectors. (e) No references are given to proper motion information. The numbers assigned by Herbig and Rao (1972), prefixed HRC in the past, have been retained for those of the 323 stars of the Second Catalog that have survived subsequent examination. Thus the new entries begin with 324 and extend through 742. The ordering is strictly in order of right ascension for 1950.0. As the result of improved coordinates, the original HRC ordering is sometimes altered. It is suggested that Catalog entries be referred to by their primary designation, which usually is in the 'name' column. In circumstances where the Catalog number must be used, it is recommended that HRC now be replaced by HBC. Note also that the letter n or an asterisk (*) which often follow the HBC number are not part of that designation, but are separate items of information. It was suggested in the Second Catalog that many of the variables in young clusters and associations that were not then known to have line emission would turn out to have bright H-alpha or Ca II, H,K lines upon closer examination. This has turned out to be so: many such stars are now included as "weak-line T Tauris" (abbreviation: wt). A large number of such stars have also been recognized as the result of X-ray surveys of obscured regions, particularly the Taurus-Auriga clouds. Walter and co-workers, who have done much of this work, have called these objects "naked T Tauri stars", or NTTS. It is our opinion that these do not constitute a separate class of pre-main sequence stars, but are a quite natural extension of the T Tauri class toward weaker line emission since the cutoff of conventional T Tauri stars at W(H-alpha) ~ 5 A was set only by the limitations of the early objective-prism or -grating surveys. The existence of substantial numbers of such stars was in fact to be expected (Herbig 1985) from the shape of the frequency distribution of W(H-alpha). We prefer the non-committal classification "wt" for these stars as a group rather than NTTS, partly because the latter implies a physical picture of the phenomenon that is still speculative. However, one kind of weak-emission star that has been omitted from the Third Catalog are the rapid-rotating G- and K-type dwarfs in young clusters, such as alpha Per and the Pleiades, most of which have emission at H-alpha. They have not been included because they lie on or near the main sequence. There are probably such stars in the field as well, and consequently we have omitted objects such as W92/NGC 2264 (= V642 Mon), Gliese 182 (= V1005 Ori), and any others that appear to be BY Dra-like variables. On the other hand, we have included many weak-emission G and K stars in the Orion Nebula region and in NGC 2264, on the grounds that they lie well above the main sequence and are therefore clearly pre-main sequence objects. The lower boundary of the Orion population, insofar as it is represented in this Catalog, thus is not well defined. Nor is it always apparent whether a late-type star having no more than weak H-alpha and Ca II emission is pre-main sequence or not. This is a relatively recent problem. The sample of emission objects that were turned up in the early H-alpha surveys were mostly classical T Tauri stars, where emission-line criteria clearly provide the identification. Foreground dMe stars were not detected, because such stars in the field and in older aggregates like the Hyades rarely have W(H-alpha) greater than about 6 A. But in younger clusters like the Pleiades, emission H-alpha has now been found in M dwarfs at W(H-alpha) values as large as 18 A, although the most are less than 12 A (Stauffer and Hartmann 1986). When such stars attract scrutiny as the consequence of some special activity, such as variability or X-ray emission, unless their luminosity is well enough known to locate them above the main sequence, there is no obvious way to distinguish a pre-main sequence star from its young main sequence counterpart. It is possible that refinement of the lithium abundance criterion might clarify this situation. It must be stressed that the stars listed here have been discovered by a variety of techniques, through searches that have been concentrated in certain areas while other regions have been almost neglected. Therefore, no one should consider the Catalog as complete even to a fairly modest limiting magnitude over any large fraction of the sky. The Catalog references those sources and papers that were available to us through March 1988. We shall be grateful for any errors that are called to our attention. The Catalog: Catalog.dat contains both real data as well as references to published papers, the latter have been listed in refs.dat. In the following text, the numbers assigned to papers in the Reference list are in [square brackets]. Within that list, for journals which exist both in the original language and in English translation, the English-language citation is given first, followed by the original in brackets (thus: Sov.Astr.-A.J. 7, 219 [7, 398]).

HBC HBC number. The running number is followed by n when the star itself is involved in, or illuminates bright nebulosity. An asterisk (*) indicates that a Remark follows the Table. --- nebu_flg Nebulosity association flag. --- rem Remark flag. See file remarks.dat --- name Star name. This is the preferred designation of the object; if a variable star name has been assigned that is always given preference. If the preferred name is too long, a > symbol indicates that it follows in col. 3. --- alt Other designation. Other designation: The conventional designations (AS, LkHalpha, Haro ...) are explained in HRC. We have found it necessary in some cases to expand the prefix system, usually abbreviating discoverers' names by two-letter symbols rather than one to avoid confusion with variable star designations (thus: CoKu for Cohen and Kuhi). We have also retained the discoverer's name for an object wherever possible, rather than substituting what might seem a more rational designation (thus: P2441/c for the companion of P2441, rather than P2441 B). The prefixes used in cols. 2, 3 are as follows: CD Cape Photographic Durchmusterung CoD Cordoba Durchmusterung CoKu Cohen and Kuhi [93] Eggen [125] Elias Tau-Aur [128]; Oph [127]; IC 5146 [126] FK Feigelson and Kriss [132] GlPe Glass and Penston [157] GM Gyulbudaghian and Magakyan [177] HaGr Hartigan and Graham [186] He 3- Henize [195] HH Herbig [211] and later publications by a variety of authors. HJ Herbig and Jones [218] HJM Hyland, Jones and Mitchell [238] HM Henize and Mendoza [196] JH Jones and Herbig [250] Kn Knacke et al. [274] LkCa Herbig, Vrba and Rydgren [219] LZK Liu, Zhang and Kimura [315] MacC MacConnell 1968: Cep-Cas; 1981: Pup MaRy Marraco and Rydgren [323] MC Cohen [90] NTTS Walter et al. [506] OgHa Ogura and Hasegawa [355] P 4 digits: Parenago [359] 1 digit: Mundt et al. [344] Par Parsamian [360] PC Parsamian and Chavira [363]: PC numbers have been assigned to all the confirmed Tonantzintla discoveries in the Orion Nebula region, but Table 1 gives only those that have no Haro 6- designations. PH Pettersson [370, 371] PP Parsamian and Petrossian [362] ROX Montmerle et al [332] RNO Cohen [85] S Sonneberg variable star San Sanduleak [417] SS 1 Sanduleak and Stephenson [419a] SS 2 Stephenson and Sanduleak [444a] SSS Strom, Strom and Stocke [450] SSV Strom, Vrba and Strom [455] St Stephenson [444] Sz Schwartz [426] TH The: see Table 3 vBH van den Bergh and Herbst [482] VSB Vasilevskis, Sanders and Balz [485] W Walker, NGC 2264 [494]; IC 5146 [495] Wa Walter [502] WK Walter and Kuhi [504] Wray Wackerling 1970 --- RAh Hours of right ascension (1950.0). The coordinates indicated by B in col. 6 were determined by one of us (KRB) 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 in col. 6 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. We do not regard either B or Aw coordinates to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those brought forward to 1950.0 have not had proper motions applied, so remain at their original epoch. h RAm Minutes of right ascension. The coordinates indicated by B in col. 6 were determined by one of us (KRB) 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 in col. 6 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. We do not regard either B or Aw coordinates to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those brought forward to 1950.0 have not had proper motions applied, so remain at their original epoch. min RAs Seconds of right ascension. The coordinates indicated by B in col. 6 were determined by one of us (KRB) 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 in col. 6 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. We do not regard either B or Aw coordinates to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those brought forward to 1950.0 have not had proper motions applied, so remain at their original epoch. s DE- Sign of declination (1950.0). --- DEd Degrees of declination. deg DEm Minutes of declination. arcmin DEs Seconds of declination. arcsec u_RAh Position uncertainty flag (:) The coordinates indicated by B in col. 6 were determined by one of us (KRB) 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 in col. 6 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. We do not regard either B or Aw coordinates to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those brought forward to 1950.0 have not had proper motions applied, so remain at their original epoch. --- r_RAh References to the position. The coordinates indicated by B in col. 6 were determined by one of us (KRB) 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 in col. 6 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. We do not regard either B or Aw coordinates to be of astrometric quality. Coordinates drawn from other sources are referenced accordingly. Those brought forward to 1950.0 have not had proper motions applied, so remain at their original epoch. --- GLON Galactic longitude. Galactic coordinates in the lII, bII system deg GLAT Galactic latitude. deg phot_range Photometric range. Photometric range if the star is a known variable, expressed in the magnitude system indicated. Values taken from the 4th edition (1985, 1987) of the General Catalogue of Variable Stars, or recent Supplements, are indicated by a C. (Note that the conventional practice is followed in that < means "fainter than".) Stars believed to be variable are indicated var. A number of stars not known to be variable have their mean, or estimated magnitudes in these columns if that magnitude is not visual or in the Johnson V system; otherwise that value is in the "V" column. --- mag_sys Code to the magnitude system. --- phot_ref Photometric references. --- l_V Inequality sign to the V magnitude. --- V V magnitude. V, B-V, U-B photometry: for stars observed more than once, unlike HRC practice (where mean values were given regardless of phase) these columns contain the values observed when the star was brightest in V and a full set of UBVRI magnitudes were measured at essentially the same time. In some cases, the colors show a substantial scatter at the same value of V; such colors are marked with a v. For those stars where there is only a small scatter about a mean V, or where a small-range cyclic variation is superposed upon irregular activity, mean rather than maximum-V values are tabulated; such stars have an m following their V magnitude. mag Vcode Code to the V magnitude. --- B-V B-V color. mag B-Vcode Code to the B-V color. --- U-B U-B color. mag U-Bcode Code to the U-B color. --- refs_UBV References to the UBV data. 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 to Table 1. An hrc means that some information given in the Second Catalog is not repeated here. --- V-R V-R color. V-R, V-I values, usually obtained simultaneously (i.e., at maximum V) with the UBV data of cols. V, B-V, U-B; this is so if the first reference in col. refs_VRI is the same as the first in col. refs_UBV. mag V-Rcode Code to the V-R color. --- V-I V-I color. mag V-Icode Code to the V-I color. --- RI_code Code to the (R,I) system. 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 [407]. --- refs_VRI References to the VRI data References to the V-R, V-I data, as described for col. refs_UBV. --- refs_IR References to the infrared magnitudes. References for infrared magnitudes, spectrophotometry and spectroscopy. However, low angular resolution far-infrared observations are not usually cited. --- refs_UVX X-ray references. UV, X-ray references: these usually refer to IUE spectroscopy and to X-ray detections from the Einstein survey. --- refs_radio Radio references. 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. --- refs_lc References to the light curves. Light curve: references to photometric studies published since HRC. An hrc means that significant references in the Second Catalog are not repeated here. --- l_vsini Inequality sign to the (v sin i). --- vsini (v sin i) data. v sin i, the projected axial rotational velocity, given only to the nearest km/s. If no radial velocity value appears in col. RV, 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. km/s vsini_code Code to the (v sin i) data. --- RV Radial velocity. Radial velocity (heliocentric, in km/s), quality, and reference. 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. The quality letter (a, b, c) expresses our judgment as to 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. For some stars we have not given the published velocities at all. Comments on several special objects (*) appear in the Remarks. km/s q_RV Quality code to the radial velocity. --- r_RV References to the radial velocity and (v sin i). --- Sp Spectral type. Spectral type. With the growing employment of red-sensitive detectors, spectral types determined since the HRC have increasingly been dependent upon criteria in the region longward of about 5000 A. However, it is apparent that significant differences exist in T Tauri spectra between such types and those assigned by the early observers of the 4000-4500 A region ([498] and Appenzeller 1985). Furthermore, it is not clear whether the spectral types of such stars change during their light variations or at other times. Therefore, it may not be possible to assign a MK type to a T Tauri star without further qualification. We have not faced up to such issues: the types given here for those stars for which more than a single classification is available are either compromise values (usually indicated by :), or in case of conflict that value which seems most reasonable to us. No indication is given of the spectral region in which the type was assigned. Several special cases are explained in the Remarks. Many of the types in HRC were based on unwidened, very low-dispersion, often underexposed Lick spectrograms; in all but a very few cases, those classifications have here been disregarded. The conventions in col. Sp are as in HRC: 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). The very fact that the 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 in col. Sp 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. --- r_Sp References to the spectral type. References to the source of the type quoted. Information in col. Sp which does not appear in the papers cited is usually from unpublished Lick material; a blank reference has that specific meaning. --- EW Equivalent width of H-alpha emission. Equivalent width of H-alpha emission (in A): These are from the original sources, and are often mean values. 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 is given followed by a v. A number of cases where the W(H-alpha) value from slit spectroscopy seems incompatible with the fact of detection of H-alpha on an objective-prism plate are mentioned in the Remarks. A hk in col. EW 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 [238]. A * means that there is a Remark (see remarks.dat) . --- EWcode Code to the equivalent width of H-alpha emission. --- refs_Halpha References to the H-alpha emission. --- refs_spec References to the spectrum data. Spectrum references show where the spectrum is reproduced (either photographically or as a scan), or the spectrum is described or discussed. --- type Type of the object. Type gives our judgment as to which group the star belongs. 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 such as those described in [203]. 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?, in the Table. -- A blank means that the observational information is inadequate. --- refs_chart References to the identification chart. Reference to an identification chart or photograph. --- location Location in the nebulosity. 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 [426]; 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) --- code Code number for reference --- reftext text reference --- HBC object HBC identification --- reftext remark text --- N.P.M. Kuin NASA/SSDOO/ADC 1995Aug03We are greatly indebted to A. Klemola for his help with the astrometric measurements, to B.F. Jones for unpublished coordinates and other assistance, and to many colleagues for preprints and unpublished information. We are also very grateful for partial support by the National Science Foundation, most recently under Grant NSF AST82-03115, for much of the observational work at Lick Observatory that is included here as well as for the preparation of the Catalog itself. UNKNOWN UNKNOWN August 1988 (George Herbig): The only differences between this tape and the original paper version are that a few small errors have been corrected, and literature citations have been provided for several papers that were only in press in June 1988. Note that the stars in Table 1 having second-line entries must have those read out of files epage1a and fpage2a, whether first-line data is being taken from cpage1, dpage2 or from epage1, fpage2. Note also that in neither paper nor tape version of this Catalogue was it possible to insert umlauts or accent marks in authors' names. The person who prepared this tape (G.H.) is hardly an an expert, and does not intend to become one. The formatting can undoubtedly be improved, but the tape is (hopefully) readable. Suggestions for the improvement of any future editions would be welcomed. August 1992 (Shiro Nishimura): Reformatting of the catalogue has been made at the Astronomical Data Analysis Center of the National Astronomical Observatory of Japan. The file, epage1 (the main file for the left page), and the file, fpage2 (the main file for the right page), were concatenated with entries of the files, epage1a and fpage2a (the second line data files), being inserted at the corresponding columns. Efforts were made to homogenize each entry by correcting column shifts and by separating code flags from numerical data. No essential change of data was, however, made except for only one case: The v sin i data for HBC 419 was rounded off from 12.5 to 13 according to the relevant description in the text file. The file, iref (the literature references in single-column format), was reconstructed into the format of one reference per line. This and together with other two files, btext and grem, were updated by deleting page numbers and surplus blank lines. Finally, corrections have been made according to the list communicated by Dr. Herbig. August 1995 (Paul Kuin): Reformatted the documentation to standard form. V_73A.xml