HIP 11952

{{Starbox observe

| epoch=J2000

| ra= {{RA|02|34|11.04689}}{{cite simbad | title=HD 16031 | access-date=March 29, 2012}}

| dec= {{DEC|-12|23|3.4570}}

| constell=Cetus{{cite news | url=http://www.space.com/15073-ancient-alien-planets-early-universe.html | title=Ancient Alien Planets Shake Up View of Early Universe | work=Space.com | date=28 March 2012 | agency=Space.com | access-date=March 29, 2012 | author=Staff, Space.com}}

| appmag_v =9.85

}}

{{Starbox character

| class = F2V-IV{{cite journal | url=http://www.aanda.org/articles/aa/pdf/forth/aa17826-11.pdf | title=Planetary companions around the metal-poor star HIP 11952 | journal=Astronomy and Astrophysics |date=March 2012|doi=10.1051/0004-6361/201117826 | bibcode=2012A&A...540A.141S | volume=540 | pages=A141|arxiv = 1208.4000 | last1=Setiawan | first1=J. | last2=Roccatagliata | first2=V. | last3=Fedele | first3=D. | last4=Henning | first4=Th. | last5=Pasquali | first5=A. | last6=Rodríguez-Ledesma | first6=M. V. | last7=Caffau | first7=E. | last8=Seemann | first8=U. | last9=Klement | first9=R. J. | s2cid=53700801 }}{{cite encyclopedia | url=http://exoplanet.eu/star.php?st=HIP+11952 | archive-url=https://web.archive.org/web/20120505093906/http://exoplanet.eu/star.php?st=HIP+11952 | url-status=dead | archive-date=May 5, 2012 | title=Notes for Star HIP 11952 | date=23 March 2012 | access-date=March 29, 2012 | encyclopedia=Extrasolar Planets Encyclopaedia | author=Schneider, Jean}}The stellar classification for this star is uncertain; please read the cited paper for more information.

| appmag_1_passband = B

| appmag_1 = 10.18

| appmag_2_passband = V

| appmag_2 =9.85

| appmag_3_passband = J

| appmag_3 = 8.790

| appmag_4_passband = H

| appmag_4 = 8.516

| appmag_5_passband = K

| appmag_5 = 8.457

| r-i =

| v-r =

| b-v =

| u-b =

| variable =

}}

{{Starbox astrometry

| radial_v=23.62

| prop_mo_ra=57.27

| prop_mo_dec=-187.74

| gal_lat=186.4962

| gal_lon=-61.7838

| parallax=8.93

| p_error=

| dist_ly=376.1

| dist_pc=115.3

| absmag_v=

}}

{{Starbox detail

| mass={{nowrap|0.83 ± 0.05}}

| luminosity=

| habitable zone=

| temperature={{nowrap|6040 ± 210}}

| metal_fe={{nowrap|–1.95 ± 0.09}}This measurement indicates the log₁₀ of the relative abundance of iron in the measured star to that of the Sun.

| radius={{nowrap|1.6 ± 0.1}}

| rotational_velocity=

| age_gyr={{nowrap|12.8 ± 2.6}}

}}

{{Starbox catalog

| names=LP 710-89, BD-13° 482, HD 16031, HIP 11952, NLTT 8361, PPM 211702, SAO 148474, TYC 5288-192-1}}

{{Starbox reference

|Simbad=HIP+11952

}}

HIP 11952 is a star in the Milky Way galaxy, located 375 light-years away from the Sun. While the spectral lines strongly indicate that the star is of spectral type F2V-IV, previous analyses have stated that the star is a G8III giant star and an F0V main-sequence star. Located in the constellation Cetus, the star has a metallicity only 1% that of the Sun. It is nearing the end of its lifetime on the main sequence, and will soon begin the transition into a red giant.

Claims of planet detection

In 2012 it was announced that HIP 11952 had two giant planets, this would have made it the oldest and most metal-poor planet host star known.{{cite news | url=http://news.nationalgeographic.com/news/2012/03/120326-oldest-planets-found-jupiter-big-bang-space-science/ | archive-url=https://web.archive.org/web/20120328065022/http://news.nationalgeographic.com/news/2012/03/120326-oldest-planets-found-jupiter-big-bang-space-science/ | url-status=dead | archive-date=March 28, 2012 | title=Oldest Alien Planets Found—Born at Dawn of Universe | work=National Geographic Daily News | date=26 March 2012 | agency=National Geographic | access-date=March 29, 2012 | author=Than, Ker}} This would have posed a challenge to planetary formation, as the chances of a planet forming so early in the Universe's history, with such a small amount of heavy elements with which to form planets, are believed to be remote.{{cite news | url=http://news.discovery.com/space/most-ancient-impossible-alien-worlds-discovered-120327.html | title=Most ancient, 'Impossible' Alien Worlds Discovered | work=Discovery News | date=27 March 2012 | agency=Discovery News | access-date=March 29, 2012 | author=O'Neill, Ian | archive-date=2 April 2012 | archive-url=https://web.archive.org/web/20120402230409/http://news.discovery.com/space/most-ancient-impossible-alien-worlds-discovered-120327.html | url-status=dead }}

Further measurements of HIP 11952 were made on 35 nights over about 150 days, from August 7, 2012, to January 6, 2013, using the newly installed high resolution spectrograph HARPS-N at the 3.58m Telescopio Nazionale Galileo telescope on La Palma Island (Canary Islands) and HARPS at the European Southern Observatory's 3.6m telescope on La Silla (Chile). Following their analysis, they were able to confidently exclude, through non-detection, the presence of the two giant planets with periods of 6.95 ± 0.01 days and 290.0 ± 16. 2 days. They also reasoned that the previously mistaken detections were probably due to instrument measurement errors. Re-analysis of the FEROS data revealed a problem with the barycentric correction used to derive the radial velocities; this error had led to the erroneous detection claim.

But a later study one using HARPS-N data in 2013, refuted the existence of both planets. The updated and more precise radial velocity measurements showed no signs of the planets previously reported. So now, HIP 11952 b is considered a false positive.

class="wikitable"

|+The HIP 11952 Planetary system

!Companion

(in order from star)

(days)

(AU)

'''b

|0.78 M_J