HH 1/2 explained

HH 1/2
Type:emission
Type2:Herbig–Haro object
Epoch:J2000.0
Constellation:Orion
Ra:[1]
Dist Ly:1500
Names:HH 1-2, HH 1/2, HH 1, HH 2

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.[2] [3] [4] [5] They are located at a distance of about 1343 light-years (412 parsec) in the constellation Orion near NGC 1999. 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.

The central region

The central region contains an opaque cloud core with an astrophysical jet[8] and a highly embedded multiple-star system that remains invisible below 3 Microns. These sources were first detected with the Very Large Array and are therefore named VLA 1 and 2.[9] The source HH 1-2 VLA 1[10] drives the HH 1/2 pair and the source VLA 2 drives the Herbig-Haro objects HH 144/145.[11] There might be even a third outflow in the central region of HH 1/2, indicating a third member.[12]

The jet towards HH 1 is visible in optical images, but the counterjet towards HH 2 was detected in the infrared with the Spitzer Space Telescope.[13]

Notes and References

  1. HH 1-2. 2020-02-15.
  2. Herbig. George H.. May 1951. The Spectra of Two Nebulous Objects Near NGC 1999.. The Astrophysical Journal. en. 113. 697–699. 10.1086/145440. 1951ApJ...113..697H. 0004-637X. free.
  3. Haro. Guillermo. May 1952. Herbig's Nebulous Objects Near NGC 1999.. The Astrophysical Journal. en. 115. 572. 10.1086/145576. 1952ApJ...115..572H. 0004-637X. free.
  4. 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. en. 123. 5. 2627–2657. 10.1086/339837. 2002AJ....123.2627B. 118242041 . 0004-6256. free.
  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. en. 150. 4. 105. 10.1088/0004-6256/150/4/105. 2015AJ....150..105R. 125612968 . 0004-6256. free.
  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. en. 86. 1232–1244. 10.1086/113003. 1981AJ.....86.1232H. 0004-6256. free.
  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. en. 413. 6857. 708–711. 10.1038/35099508. 11607024. 2001Natur.413..708P. 13878953 . 0028-0836.
  8. Bohigas. J.. Torrelles. J. M.. Echevarria. J.. Canto. J.. Enriquez. R.. Firmani. C.. Gutierrez. L.. Ruiz. E.. Salas. L.. December 1985. Optical images of the region around HH1 and HH2 taken with the MEPSICRON system.. Revista Mexicana de Astronomía y Astrofísica. en. 11. 149–157. 0185-1101. 1985RMxAA..11..149B.
  9. Rodríguez. Luis F.. Delgado-Arellano. Víctor G.. Gómez. Yolanda. Reipurth. Bo. Torrelles. José M.. Noriega-Crespo. Alberto. Raga. Alejandro C.. Cantó. Jorge. February 2000. New VLA Observations of the HH 1-2 Region: Evidence for Density Enhancements Moving along the Axis of the VLA 1 Radio Jet. The Astronomical Journal. en. 119. 2. 882–889. 10.1086/301231. 2000AJ....119..882R. 59520064 . 0004-6256.
  10. HH 1-2 VLA 1. 2020-02-15.
  11. Reipurth. Bo. Heathcote. Steve. Roth. M.. Noriega-Crespo. A.. Raga. A. C.. May 1993. A New Herbig-Haro Flow in the HH 1--2 Complex. The Astrophysical Journal. en. 408. L49. 10.1086/186828. 1993ApJ...408L..49R. 0004-637X. free.
  12. Hester. J. Jeff. Stapelfeldt. Karl R.. Scowen. Paul A.. July 1998. Hubble Space Telescope Wide Field Planetary Camera 2 Observations of HH 1-2. The Astronomical Journal. en. 116. 1. 372–395. 10.1086/300396. 1998AJ....116..372H. 0004-6256. free.
  13. Noriega-Crespo. A.. Raga. A. C.. May 2012. Spitzer Observations of the HH 1/2 System: The Discovery of the Counterjet. The Astrophysical Journal. en. 750. 2. 101. 10.1088/0004-637X/750/2/101. 1203.1032. 2012ApJ...750..101N. 1793062 . 0004-637X.

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