HH 1/2

HH 1/2
Emission nebula
Herbig–Haro object
Hubble Space Telescope WFC3 image of HH 1/2 and the jet pointing to HH 1 (right)
Observation data: J2000.0 epoch
Right ascension05h 36m 22.8s[1]
Declination−06° 46′ 03″[1]
Distance1500[2] ly
ConstellationOrion[2]
DesignationsHH 1-2, HH 1/2, HH 1, HH 2
See also: Lists of nebulae

The Herbig-Haro objects HH 1/2 are the first such objects to be recognized as Herbig-Haro objects and were discovered by George Herbig and Guillermo Haro.[3][4][2][5] They are located at a distance of about 1343 light-years (412 parsec) in the constellation Orion near NGC 1999.[3] HH 1/2 are among the brightest Herbig-Haro objects in the sky and consist of a pair of oppositely oriented bow shocks, separated by 2.5 arcminutes (a projected separation of about 1.1 light year). The HH 1/2 pair were the first Herbig-Haro objects with detected proper motion[6] and HH 2 was the first Herbig-Haro object to be detected in x-rays.[7] Some of the structures in the Herbig-Haro Objects move with a speed of 400 km/s.[2]

  1. ^ a b "HH 1-2". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-15.
  2. ^ a b c d Bally, John; Heathcote, Steve; Reipurth, Bo; Morse, Jon; Hartigan, Patrick; Schwartz, Richard (May 2002). "Hubble Space Telescope Observations of Proper Motions in Herbig-Haro Objects 1 and 2". The Astronomical Journal. 123 (5): 2627–2657. Bibcode:2002AJ....123.2627B. doi:10.1086/339837. ISSN 0004-6256. S2CID 118242041.
  3. ^ a b Herbig, George H. (May 1951). "The Spectra of Two Nebulous Objects Near NGC 1999". The Astrophysical Journal. 113: 697–699. Bibcode:1951ApJ...113..697H. doi:10.1086/145440. ISSN 0004-637X.
  4. ^ Haro, Guillermo (May 1952). "Herbig's Nebulous Objects Near NGC 1999". The Astrophysical Journal. 115: 572. Bibcode:1952ApJ...115..572H. doi:10.1086/145576. ISSN 0004-637X.
  5. ^ Raga, A. C.; Reipurth, Bo; Castellanos-Ramírez, A.; Chiang, Hsin-Fang; Bally, J. (October 2015). "High Angular Resolution Multi-line Study of HH 1 and 2". The Astronomical Journal. 150 (4): 105. Bibcode:2015AJ....150..105R. doi:10.1088/0004-6256/150/4/105. ISSN 0004-6256. S2CID 125612968.
  6. ^ Herbig, G. H.; Jones, B. F. (August 1981). "Large proper motions of the Herbig-Haro objects HH 1 and HH 2". The Astronomical Journal. 86: 1232–1244. Bibcode:1981AJ.....86.1232H. doi:10.1086/113003. ISSN 0004-6256.
  7. ^ Pravdo, Steven H.; Feigelson, Eric D.; Garmire, Gordon; Maeda, Yoshitomo; Tsuboi, Yohko; Bally, John (October 2001). "Discovery of X-rays from the protostellar outflow object HH2". Nature. 413 (6857): 708–711. Bibcode:2001Natur.413..708P. doi:10.1038/35099508. ISSN 0028-0836. PMID 11607024. S2CID 13878953.