시작하기     To Survive in the Universe    
Inhabited Sky
    News@Sky     천체사진     컬렉션     포럼     Blog New!     질문및답변     출판     로그인  

HD 98044


내용

사진

사진 업로드

DSS Images   Other Images


관련 글

X-Ray-Emitting Stars Identified from the ROSAT All-Sky Survey and the Sloan Digital Sky Survey
The ROSAT All-Sky Survey (RASS) was the first imaging X-ray survey ofthe entire sky. Combining the RASS Bright and Faint Source Catalogsyields an average of about three X-ray sources per square degree.However, while X-ray source counterparts are known to range from distantquasars to nearby M dwarfs, the RASS data alone are often insufficientto determine the nature of an X-ray source. As a result, large-scalefollow-up programs are required to construct samples of known X-rayemitters. We use optical data produced by the Sloan Digital Sky Survey(SDSS) to identify 709 stellar X-ray emitters cataloged in the RASS andfalling within the SDSS Data Release 1 footprint. Most of these arebright stars with coronal X-ray emission unsuitable for SDSSspectroscopy, which is designed for fainter objects (g > 15 [mag]).Instead, we use SDSS photometry, correlations with the Two Micron AllSky Survey and other catalogs, and spectroscopy from the Apache PointObservatory 3.5 m telescope to identify these stellar X-raycounterparts. Our sample of 707 X-ray-emitting F, G, K, and M stars isone of the largest X-ray-selected samples of such stars. We derivedistances to these stars using photometric parallax relationsappropriate for dwarfs on the main sequence, and use these distances tocalculate LX . We also identify a previously unknowncataclysmic variable (CV) as a RASS counterpart. Separately, we usecorrelations of the RASS and the SDSS spectroscopic catalogs of CVs andwhite dwarfs (WDs) to study the properties of these rarer X-ray-emittingstars. We examine the relationship between (fX /fg) and the equivalent width of the Hβ emission line for 46X-ray-emitting CVs and discuss tentative classifications for a subsetbased on these quantities. We identify 17 new X-ray-emitting DA(hydrogen) WDs, of which three are newly identified WDs. We report onfollow-up observations of three candidate cool X-ray-emitting WDs (oneDA and two DB (helium) WDs); we have not confirmed X-ray emission fromthese WDs.Includes observations obtained with the Apache Point Observatory 3.5 mtelescope, which is owned and operated by the Astrophysical ResearchConsortium.

새 글 등록


관련 링크

  • - 링크가 없습니다. -
새 링크 등록


다음 그룹에 속해있음:


관측 및 측정 데이터

별자리:큰곰자리
적경:11h17m35.94s
적위:+67°53'00.0"
가시등급:8.224
거리:92.937 파섹
적경상의 고유운동:-57.7
적위상의 고유운동:-18.4
B-T magnitude:8.736
V-T magnitude:8.267

천체목록:
일반명   (Edit)
HD 1989HD 98044
TYCHO-2 2000TYC 4392-1680-1
USNO-A2.0USNO-A2 1575-03152529
HIPHIP 55162

→ VizieR에서 더 많은 목록을 가져옵니다.