V733 Cep (Persson’s Star): A New FU Orionis Object in Cepheus

Persson recently found that a faint star had appeared in a cloud in Cepheus. A CCD image shows a R ∼ 17.3 nebulous star, now known as V733 Cep, located in the L1216 = Cep F cloud at the apex of a cavity in the cloud. Infrared photometry indicates a modest infrared excess. Optical spectroscopy shows a well-defined Li I λ6707 line, and blueshifted absorption troughs at the Hα and Na I D lines extending to at least 200 km s-1, indicative of a massive fast wind. An infrared 1-4 μm spectrum of V733 Cep shows the presence of strong water vapor features, and is almost identical to a similar IR spectrum of FU Ori that is reddened by AV = 8 mag. Assuming an intrinsic energy distribution similar to that of FU Ori, V733 Cep has a luminosity of about 135 L⊙ at the assumed distance of 800 pc. The star was detected by the Midcourse Space Experiment satellite at 8.3 μm, but not by IRAS. Nor is it detected at 850 μm, indicating that while the star possesses circumstellar material it is not surrounded by a significant cool envelope. A 12CO(3-2) map shows what appears to be a small molecular outflow along the same axis as the cavity seen in optical images. There is evidence for a limited amount of other low- and medium-mass star formation in the Cep F cloud. The totality of the evidence strongly indicates that V733 Cep is a new FU Ori-type object that must have erupted sometime between 1953 and 1984.

[1]  T. Umemoto,et al.  Erratum: Atlas and Catalog of Dark Clouds Based on Digitized Sky Survey I , 2005 .

[2]  G. Lodato,et al.  Massive planets in FU Orionis discs: implications for thermal instability models , 2004, astro-ph/0406264.

[3]  C. Aspin,et al.  The FU Orionis Binary System and the Formation of Close Binaries , 2004 .

[4]  I. Hook,et al.  The Gemini–North Multi‐Object Spectrograph: Performance in Imaging, Long‐Slit, and Multi‐Object Spectroscopic Modes , 2004 .

[5]  Jonathan P. Williams,et al.  Modeling the millimeter emission from the Cepheus A young stellar cluster: Evidence for large scale collapse , 2004, astro-ph/0404215.

[6]  John T. Rayner,et al.  Spextool: A Spectral Extraction Package for SpeX, a 0.8–5.5 Micron Cross‐Dispersed Spectrograph , 2004 .

[7]  C. Aspin,et al.  Two Embedded Young Stellar Objects in NGC 2264 with FU Orionis Characteristics , 2003 .

[8]  C. Ledoux,et al.  The UVES Paranal Observatory Project: A Library of High- Resolution Spectra of Stars across the Hertzsprung-Russell Diagram , 2003 .

[9]  G. Herbig,et al.  High-Resolution Spectroscopy of FU Orionis Stars , 2003, astro-ph/0306559.

[10]  John T. Rayner,et al.  SpeX: A Medium‐Resolution 0.8–5.5 Micron Spectrograph and Imager for the NASA Infrared Telescope Facility , 2003 .

[11]  U. Exeter,et al.  The discovery of low-mass pre-main-sequence stars in Cepheus OB3b , 2003, astro-ph/0302205.

[12]  H Germany,et al.  A Method of Correcting Near‐Infrared Spectra for Telluric Absorption , 2002, astro-ph/0211255.

[13]  B. Reipurth,et al.  Evolution of the Fu Orionis Object BBW 76 , 2002 .

[14]  R. Bachiller,et al.  Chemically active outflow L 1157 , 2001 .

[15]  G. Sandell,et al.  On the Similarity of FU Orionis Stars to Class I Protostars: Evidence from the Submillimeter , 2001 .

[16]  T. Mikami,et al.  Hα Emission Stars in the Cepheus OB3 Region , 2001 .

[17]  B. Reipurth.  Disintegrating Multiple Systems in Early Stellar Evolution , 2000 .

[18]  A. Fabian,et al.  ROSAT observations of Cepheus OB3: the discovery of low‐mass stars , 1999 .

[19]  M. Meyer,et al.  Spectroscopy of Brown Dwarf Candidates in the ρ Ophiuchi Molecular Core , 1998, astro-ph/9810508.

[20]  M. Maldoni,et al.  A study of the 2.5-25μm spectrum of H2O ice , 1998 .

[21]  C. Aspin,et al.  Infrared Spectroscopy of Herbig-Haro Energy Sources , 1997 .

[22]  M. Irwin,et al.  Ultra-Cool M Dwarfs Discovered by QSO Surveys.I: The APM Objects , 1997 .

[23]  L. Hartmann,et al.  The FU Orionis Phenomenon , 1996 .

[24]  D. Syer,et al.  Low-mass companions to T Tauri stars: a mechanism for rapid-rise FU Orionis outbursts , 1995, astro-ph/9511030.

[25]  D. Lin,et al.  USING FU ORIONIS OUTBURSTS TO CONSTRAIN SELF-REGULATED PROTOSTELLAR DISK MODELS , 1993, astro-ph/9312015.

[26]  Hideki Takami,et al.  Detection of water vapor in T Tauri stars , 1993 .

[27]  S. Strom,et al.  The Discovery of Two FU Orionis Objects in L1641 , 1993, astro-ph/9305012.

[28]  L. Hartmann,et al.  RNO 1B/1C: a double FU Orionis system , 1993 .

[29]  H. Staude,et al.  The FU Orionis--Type Spectrum and Bipolar Outflow of Parsamyan 21 , 1992 .

[30]  I. Bonnell,et al.  A binary origin for FU Orionis stars , 1992 .

[31]  L. Hartmann,et al.  Pre-main-sequence disk accretion in Z Canis Majoris , 1989 .

[32]  P. Roche,et al.  Infrared spectroscopy of dust in the Taurus dark clouds: ice and silicates , 1988 .

[33]  Scott J. Kenyon,et al.  Accretion disk models for FU orionis and V1057 Cygni: detailed comparisons between observations and theory , 1988 .

[34]  High spectral resolution infrared observations of V1057 Cygni , 1987 .

[35]  D. Lester,et al.  The 2 Micron Spectrum of L1551 IRS 5 , 1987 .

[36]  Further evidence for disk accretion in FU Orionis objects , 1987 .

[37]  L. Hartmann,et al.  On the nature of FU Orionis objects , 1985 .

[38]  R. Mundt,et al.  The optical spectrum of L 1551 IRS 5. , 1985 .

[39]  G. Rieke,et al.  The interstellar extinction law from 1 to 13 microns. , 1985 .

[40]  J. Wouterloot,et al.  The star-forming region in Cepheus A , 1984 .

[41]  C. Fridlund,et al.  FAR-INFRARED AND CO OBSERVATIONS OF CEP-F - IMPLICATIONS FOR STAR FORMATION IN CEPHEUS-OB3 , 1983 .

[42]  R. Larson.  The FU Orionis mechanism , 1980 .

[43]  I. Gatley,et al.  Far-infrared observations of the Cepheus OB3 molecular cloud , 1979 .

[44]  A. Sargent.  Molecular clouds and star formation. II. Star formation in the Cepheus OB3 and Perseus OB2 molecular clouds , 1979 .

[45]  S. Ridgway,et al.  The composite spectra of FU Orionis stars , 1978 .

[46]  A. Sargent.  Molecular clouds and star formation. I. Observations of the Cepheus OB3 molecular cloud. , 1977 .

[47]  George H. Herbig,et al.  Eruptive phenomena in early stellar evolution. , 1977 .

[48]  M. Cohen.  Infrared Observations of Young Stars—VI A 2- TO 4-Micron Search for Molecular Features , 1975 .

[49]  D. Crawford,et al.  Four-color and Hbeta photometry for open clusters. VI. The association III Cephei. , 1970 .

[50]  R. Garrison.  Spectral classification in the association III Cephei and the ratio of total-to-selective absorption. , 1970 .

[51]  G. Herbig.  On the interpretation of FU orionis , 1966 .

[52]  N. Woolf,et al.  Infrared Spectra of Red-Giant Stars. , 1964 .

[53]  A. Blaauw.  The O Associations in the Solar Neighborhood , 1964 .

[54]  B. T. Lynds.  Catalogue of Dark Nebulae. , 1962 .

[55]  S. Sharpless.  A Catalogue of H II Regions. , 1959 .

[56]  A. Blaauw,et al.  Photoelectric Photometry of the Association III Cephei. , 1959 .